1 ar g A\\E-UNIVER% o O O c$" I 3 f O i ^ ^r^ tVv-1 ffi fi^^ ^ < s cz nj 5\\E UNIVERS/A r~ ge . <$UIBRARYQr * 5 1 ir" ^ ^ =3 .^' ^ K ^ I i^t .^ o *tr 'JJIdJfA ^JUJ, A A\\EUNIVER s = ^ ^ 3 V fe ^UIBRARYQr ^.[|B 5 ^1 ff 1 ^ s i? S I 5 s %ojnv3-jo^ %OJF 1 S y ^?AW | I i I 2 I g 1 ^IOS^ 2 = ^-^ ( %3AI S**^ "fr/l M-UBRARYQr i ? Cyclopedia "f Motion- Picture Work A General Reference Work on THE OPTICAL LANTERN, MOTION HEAD, SPECIFIC PROJECTING MACHINES, TALKING PICTURES, COLOR MOTOGRAPHY, FIXED CAMERA PHOTOGRAPHY, MOTOGRAPHY, PHOTO-PLAYS, MOTION-PICTURE THEATER, MANAGEMENT AND OPERATION, AUDIENCE, PROGRAM, ETC. Prepared by DAVID S. HULFISH TECHNICAL EDITOR, "THE NICKELODEON; " SPECIALIST IN MOTION PICTURES Illustrated with Over Three Hundred Engravings TWO VOLUMES CHICAGO AMERICAN TECHNICAL SOCIETY 1914 COPYRIGHT, 1911 AMERICAN SCHOOL OF CORRESPONDENCE COPYRIGHT, 1911 BY AMERICAN TECHNICAL SOCIETY Entered at Stationers' Hall, London All Rights Reserved theater Arts 77? 85O . y*2 Foreword TWENTY years ago the motion picture was a child's toy. Today it is the basis of a business giving profitable employment to thousands of workers, offering amuse- ment and education to millions of people, and involving an investment of capital that places it among the world's great industries. C, The motion-picture maker sets up his whirring camera in the wilds and the crowded city alike. He records the downfall of kings and the inauguration of presidents, the horrors of great disasters and the deeds of popular heroes; he spreads before us in moving panorama all that is interesting in nature and in man's work, in drama and in real life. Every large city has its motion-picture factory, and every village its motion-picture theater. Into communities too small to support a theater regu- larly comes the traveling exhibitor with his portable outfit, and shows in town hall, church, or country school house. C, For so important an industry a book of reference and instruction is more than merely justified ; it is demanded. The motion-picture field is broadening day by day ; the details of the business are becoming more multitudinous with each advance. The worker in one branch of activity must have some knowledge of all the branches to be able to get the best results in his own work. This Cyclopedia of Motion-Picture Work is the first compilation to cover adequately the entire field. C. The Art of the motion picture comprises two principal industries: the manufacturing, and the exhibiting, of film pictures. Both of these fields are covered by this Cyclopedia. The worker in either will be deeply interested in the detail and technique of the other, and will profit by that broader knowledge. The beginner requires a complete knowledge of both branches to fit himself for work in either branch. C. The drawings, diagrams, and photographs incorporated into the Cyclopedia have been prepared especially for this work; and their instructive value is as great as that of the text itself. They have been used to illustrate and expand the text, and not as a medium around which to build the text. Both drawings and diagrams have been rendered as simply as was compatible with their correctness, with a view to making them as nearly as possible self-explanatory. C. The Cyclopedia is a compilation of many of the most valuable Instruction Papers of the American School of Correspondence, and the method adopted in its preparation is that which this School has developed and employed so successfully for many years. This method is not an experiment, but has stood the severest of all tests that of practical use which has demon- strated it to be the best yet devised for the education of the busy man. fable of Contents VOLUME II PHOTOGRAPHY . . . . By D. S. Hulfish Page *11 Camera Images Lenses Focus Aberration Astigmatism Shutters Plate- holder Darkroom Camera Operation Principal Object Background Light- ing Point of View Distortion Dry Plates and Films Exposure Development Ruby Lamp Washing Focusing Developing Formulas Printing Papers Lens Printing Lantern Slides Stereographs Panoramas Telephotography Orthochromatic Photography Colored Photographs Tri-color Photography Orthochrome Plates MOTOGRAPHY . . . , '. v . . By D. S. Hulfish Page 69 Chronophotography Kinephotography Subjects: Travels, Industrials, Current Events, Dramas, Comedies, Chases, Trick Pictures Production Author Plot Scenario Drama Scrip Comedy Scrip Chase and Trick Scrip Trick Notes Travel Scrip Travel and Comedy Scrip Industrial Scrip Producer Studios Properties Costumes Actors Rehearsals Producing a Drama Salesman Film Industry Lectures Release Dates Shipments of Films Contracts Title Posters Reproduction [Photographer Raw Film Storage Perforation Camera Man Camera Loading Film Holders Turning Crank Setting Up Camera Focusing Control of Image Shutter Exposure Reversing; Finders Indicator Marker Development of Films Making Titles Printing Color- ing Films Waterproofing Photographic Equipment Chronophotography Trick Pictures MOTION-PICTURE THEATER . . . By D. S. Hulfish Page 165 Management The "Sick" Theater-*-Competition Traffic Managing a Theater for Profit Starting a Theater Location Financing Store- Front City Theater Sloping Floor Stage Typical Program Country Theater Airdome Audi- ences Advertising Poster Service Electric Signs Special Programs Renting Films Song Slides Automatic Music Vaudeville Accounts Dull Season Tickets and Chopper Side Lines for Profit ELECTRICAL PRINCIPLES ... , ' ; . , '. . Page 213 Current Electromotive Force Resistance Ohm's Law Primary Cells Stor- age Batteries Electromagnetism Circuits Wiring Methods Planning an Installation Wiring an Office Building Switchboard Wiring Diagrams Cut- out Panels Bushings Fuse Boxes Fuses Arc Lamp for Moving-Picture Machines Mercury-Arc Rectifiers for Motion Pictures REVIEW QUESTIONS . . ..'' .' ... . Page 287 INDEX . .. . * . . . Page 297 * For page numbers, see foot of pages. ~ PHOTOGRAPHY THEORY The making of photographs may be divided into three very general or theoretical steps : First, producing an image of the scene or object of which it is desired to make a photograph. Second, reco ding the image in permanent form. Third, copying, multiply- ing, or reproducing the image into as many finished photographs as may be desired. Any of these steps may be accomplished in any of several ways by the photographer, according to the results which he desires to attain, or according to the limitations of the apparatus which he has available. Thus, images usually are formed for photography by means of a lens; but if the photographer has no lens, or arbitrarily decides not to use it, he may form an image without it. The image formed being composed of rays of light of different strengths, the second step taken by placing in the image a surface bearing a substance which is sensitive to light and which will be discolored to different degrees by the different strengths of the different rays and by the spots of light formed by them in the image. This second step produces the record of the image, and from it a number of finished photographs may be produced in, a manner not altogether unlike the production of several thousand newspapers by a printing press after the typesetters have made ready the printing types and the engravers have made ready the printing picture plates. MECHANICAL DETAILS Camera. The camera is a dark box within which the photog- rapher forms the image. The light is admitted to the camera dur- ing the making of the photograph, and in most cameras during the preparation for the photograph and the proper adjustment of the camera for forming the desired image. Pin=hole Image. To understand just how the image is formed in the camera, perform the following experiment: Copyright, 1911, by American School of Correspondence. 11 2 THE MOTION PICTURE Take a paper box, white inside, about the size of a shoe box. Remove half of the lid. In the middle of one end of the box, punch a hole with a darning needle, making a hole about T V inch in diameter, with smooth edges. Place the box in the window, the hole toward the street, and with the half-lid on that part of the top of the box near the street. Draw the shade to the top of the box, and obscure the remainder of the window as well as other windows of the room so that the only light received will be through the small hole in the end of the box the pin-hole as it is termed in photography, Fig. 1. On the inside of the box, at the end opposite the pin-hole, there will / 'MAGE Fig. 1. Pin-hole Image be formed an image of the objects upon the opposite side of the street. The image may be viewed through the open half of the top of the box, and will be seen a living image, in natural colors, but inverted, its size depending upon the length of the box. Try it with boxes of different lengths, or moving a white card in the box. Inverted Image. The reason why the image is inverted is shown in Fig. 2, in which the object, the pin-hole, and the image are rep- resented. All rays of light pass in straight lines, and all the light from the top of the tree at the right which gets through the pin-hole passes in a straight line to the bottom of the image at the left; light from the bottom of the tree goes to the top of the image. This is true for every point of the view; hence, the view is inverted in the image. 12 PHOTOGRAPHY 3 Now with a lead pencil, enlarge the pin-hole until the pencil can pass through. Note the difference in the image. It is blurred. Each point in the scene makes a spot in the image as large as the hole in the box; yet the image as a whole is brighter. A spectacle lens placed over the hole in the box might make the image sharp, but at this point the pin-hole experiment may be abandoned and the working of the photographer's camera as it is commercially used may be taken up to complete the study of the first step in theory, or the formation of the image in practice. Buying a Camera. The learner who intends either to make moving pictures after learning still photography, or to make good still photographs, must first purchase a tripod camera. Concern- ing the work of hand cameras, a photographer handling amateur work at a holiday resort is quoted as saying that of more than a Fig. 2. Inverted Image thousand negatives developed by him in one summer there were not twenty good pictures and hardly forty good negatives. Only with the tripod camera can the photographer know what he is doing and then operate his camera intelligently and successfully. The camera purchased for intelligent work must be either 4-inch by 5-inch size, with bellows draw of 12 inches or more, or 5-inch by 7-inch size, with bellows draw of 15 inches or more. Smaller than 4 by 5 is too small for intelligent work by the ambitious amateur, and larger than 5 by 7 is too heavy for amateur work. In either case, the camera should have a single swing, and must have a rising front and holders for glass plates; it may have a convertible rectilinear lens or a more expensive convertible anastigmatic lens, but in either case the lens must be convertible and should be equipped with an iris diaphragm and an automatic shutter. The usefulness of each of these features will appear as the operation of the camera is de- 13 4 THE MOTION PICTURE scribed. A camera 4 by 5 may be had at a catalogue price of $25.00 or more, and a camera 5 by 7 at $33.00 or more, filling all require- ments. Two extra plate-holders should be bought, that six plates may be carried into the field. A tripod and focusing cloth complete the necessary field equipment, with the possible addition of an exposure meter. Construction of Camera. The body of the camera consists of the back frame, the front frame, and a base. The base connects the back and front frames and upon it the front frame moves as upon a track. Connecting the back and the front is the bellows. The front carries the lens, mounted upon a detachable lens board; the back carries the ground glass or focusing screen, and permits the insertion of one of the plate-holders in such a manner that when the plate-holder is inserted the ground glass is pushed out of its normal position and the glass plate within the holder occupies the position formerly held by the ground glass. Place the camera in the window as the shoe box was, and open shutter and diaphragm. The shutter is opened by setting its index to "T," or "Time," and operating it with the rubber bulb. The diaphragm is opened by setting its index to the lowest number, probably 8. Extend the bellows until a sharp image is seen upon the ground glass. Look at the ground glass, not through it. If the back of the camera and the operator's head are covered with the focusing cloth, it will not be necessary to darken the room for this experiment. By moving the camera front to different positions, it will be observed that the image is sharp in only one position. This is the position of focus of the lens. Lenses. The lens is composed of a barrel carrying the shutter and iris diaphragm in its middle portion and carrying at each end a "lens cell," or metal mount, into which the glasses of the lens are fixed. The glasses may be removed from the lens barrel by un- screwing their mounts from the barrel. Unscrew the front lens cell and extend the bellows until the image upon the ground glass is sharp again. This is the focus for the "back combination," or that cell which still remains in the lens. The bellows is longer, the image is larger. Sometimes the front combination of the lens is of still longer focus than the back combination, giving an image still larger, but with still longer extension of the bellows. 14 PHOTOGRAPHY 5 Replace the lens cells. Select in the image a distant object, such as a chimney 500 feet away. Focus sharply upon it by moving Pig. 3. Pin-hole without Lens the camera front until the cnimney is sharp. Note a near object, a house or tree within 50 feet; it is not sharp. To focus sharply upon the near object, it is necessary to extend the bellows slightly. Now the distant object is not sharp. Try to place the focus between the two; then reduce the iris diaphragm to 32 or even 64. Now both distant and near objects are sharp. Remove both lens cells. Shut the iris diaphragm as close as it will move. Look upon the ground glass; the image of the shoe box is there. Move the bellows to different lengths; the size of the Fig. 4. Pin-hole with Lens pin-hole image is changed but it is in as good focus in one place as another. The pin-hole image has no definite length, and everything, near and far, is in focus. Replace the lens cells. With the diaphragm 15 6 THE MOTION PICTURE still at its smallest size, the lens makes the image sharper, but a position may be found at which everything seems to be in focus, both near and far objects. This is called the condition of universal focus. Focal Length. The distance from the ground glass to the center- of the lens when the image is in focus upon the glass, is called the focal length of the lens, and usually is expressed in inches. The focal length of the two combinations or cells of the lens when used together is shorter than the focal length of either of them. With a 5 by 7 lens, the complete lens should have a focal length of 7 inches or a little more; each of the combinations alone should be about 12 inches, or one of them about 11 and the other about 14 inches. Fig. 5. Lens Image Figs. 3 and 4 show the action of the lens. The glass of the lens bends the rays of light, which proceed from a point in the sub- ject until they reach the lens and then are bent by the lens to approach until again they meet in a point, making a sharper spot of light on the ground glass in Fig. 4 with the lens than in Fig. 3 where the pin-hole without the lens is shown. This is true of all points of the subject, as shown in Fig. 5. The distance from the lens to the place where the ray again comes to a point depends upon the strength of the lens in bending the rays, and this distance is the focal length of the lens. In Fig. 6 the back lens cell alone bends the light to bring it to a focus; while in Fig. 7 both front and back lens cells bend the light, one after the 16 PHOTOGRAPHY 7 other, bending it to a much greater extent, bringing it to a focus in a shorter distance, giving a shorter focus or shorter lens length, and producing of course a smaller image on the ground glass. Measuring Length. Without a camera, a lens may be measured approximately by focusing the image of the sun upon any convenient surface, such as a small card, then measuring with a ruler the distance from the middle of the lens barrel to the card. With a camera, focus upon a very distant object, and measure from the middle of the lens barrel to the ground glass. A more accurate method, where a camera of sufficiently long bellows is available, is to focus upon any close object until the image on the ground glass is exactly the size of the object. Measure the distance between the object and the ground glass and divide by four. To make this measurement con- veniently, cut two slips of paper of equal length and attach one to the ground glass and the other to the glass of the window. Place the camera on a table where it may slide toward the window to change the size of the image. Use the largest diaphragm opening. WTien the edges of the image of the slip of paper are sharp and when the image on the ground glass and the slip of paper on the ground glass are of the same length, the distance between the object and the image will be four times the focal length of the lens. Fig. 7. Short-Focus Lens Position of Diaphragm Opening. The influence upon the image of the diaphragm opening, or "stop," and of its position with reference to the lens is shown in Figs. 8, 9, and 10. In each of these figures, there are shown a photographic subject composed of straight 17 8 THE MOTION PICTURE lines, a lens, a stop opening, and an image of the subject formed by the lens through the diaphragm. In each figure, the subject and the image are shown in a front view, while the lens and diaphragm Fig. 8. Barrel Distortion are shown in side view, or rather in sectional view as though cut through the middle. In Fig. 8, the diaphragm opening is in front of the lens, between the lens and the subject to be photographed. The result is a bend- ing of all the straight lines of the image, drawing the ends of the lines toward the middle line of the image, both horizontally and vertically. This form of distortion is called barrel distortion. In Fig. 9, the diaphragm opening is behind the lens, between the lens and the image. This results in bending the lines of the image in the opposite direction, and produces what is called a pin-cushion dis- tortion. In Fig. 10, a double lens is shown, the glasses of the lens being divided into two cells with the diaphragm or stop between them. With such an arrangement the pin-cushion distortion of the front lens cell is just balanced by the barrel distortion of the back lens cell, and the resulting image has all its lines straight. Such a lens is called a rectilinear lens. To avoid distortion, the diaphragm Fig. 9. Pin-cushion Distortion must be placed between the two cells at the proper distance from both. Of the two forms of distortion shown in Figs. 8 and 9, the barrel distortion is the less objectionable, and when a single lens is used, it should be placed in the back end of the lens tube, even 18 PHOTOGRAPHY 9 though it be the front cell of the complete lens. The single lens serves satisfactorily for landscape and portrait work, in either of which it may be said there are no straight lines In photographing Fig. 10. Rectilinear Lens architectural subjects, where the straight lines of the sides of build- ings are near the edge of the plate, and in interiors, only the rec- tilinear lens may be used if passable results are desired. Focusing. Bringing the desired image into focus is controlled by the position of the ground glass at the proper distance from the lens, and also by the size of the opening in the diaphragm or stop. Every point in the image is formed by a mass of light rays which is conical in form, as big as the stop opening at the lens, and tapering down to a point at or near the ground glass. When the exact tip of this cone is upon the surface of the ground glass, the point is in focus and sharp in the image. When the tip of the cone is a little behind or in front of the ground glass, the point is slightly blurred, but if not too much blurred it may be said to be still in focus. The amount of blur depends upon the size of the cone at the place where the ground glass is met. Fig. 11 shows a lens with Fig. 11. Lens without Diaphragm Stop a large stop opening. The point B of the subject is in focus at the point b of the image; the point A of the subject is in focus at the point a of the image. With the ground glass at the vertical line, through a the point A will be sharp and the point B will be blurred in the image. With the ground glass at the vertical line, through 6 the point B will be sharp in the image and the point A will be blurred. 19 10 THE MOTION PICTURE Fig. 12 shows the same system with a smaller stop opening. The cone from the point A is smaller where it crosses the vertical line through b, hence the blur will be less, and the focus more nearly Fig. 12. Lens with Diaphragm Stop correct. With the ground glass midway between the points a and b, both will be slightly blurred, but the blur will be less with the smaller top opening, Fig 12 "Depth of field" in an image refers to the distance from the nearest object in focus to the farthest object in focus. With the smaller stop opening, the depth of field is increased. Spherical Aberration. Lenses ground by machines present spherical surfaces upon both sides, although not of concentric spheres. Such a lens bends a ray of light to a greater degree when the ray passes through the lens near the edge than when the ray passes through the lens near the center. This is illustrated in Fig. 13. By the greater bending, the rays from the object C which pass near the edge of the lens are brought to focus on the line c, while those through the central portion are brought to focus upon the line c'. This defect in the lens is reduced by the use of a lens which is meniscus in form, having one convex and one concave surface, as illustrated in Fig. 14. It is reduced also by the use of a smaller stop opening, as illustrated in Fig. 15. Pig. 13. Spherical Aberration in Convex Lens Chromatic Aberration. The light rays of different colors are affected to different degrees by the refractive attribute of the glass of the lens. The violet light is bent through a greater angle than the yellow light, and the remaining colors, as well as the ultra-violet rays, are changed in direction through different angles. This pro- 20 PHOTOGRAPHY 11 duces the effect of bringing the different colors to focus at different distances from the photographic lens of the simplest type, viz, of a single meniscus piece of glass. The principle involved is the same Fig. 14. Spherical Aberration in Meniscus Lens as that by which a single ray of white light is separated by a prism into its elementary colors, a band of colored rays being secured by the separation of the single white ray. The effect in a photographic lens is shown in Fig. 16. The ray of white light from the point D of the subject is brought to focus in several different points according to the colors into which the light is separated. The yellow light is brought to focus at the line d, while the violet light is brought to focus on the line d'. Of all the colors composing white light, yellow affects the eye to the greatest degree and, consequently, in focusing the camera by looking at the image upon the ground glass, the yellow light is appreciated by the eye and the ground glass is brought to that position in which the yellow rays are in focus. At the same time, the red and blue rays are so nearly in focus that they unite to give the appear- ance of white light in focus upon the screen. When the sensitive plate is placed in the camera, occupying the position of the ground glass, and the light is permitted to fall upon it through the lens, Fig. 15. Spherical Aberration Reduced by Diaphragm Stop the conditions of appreciation of the light are changed. The sensitive plate is most sensitive to the blue the violet and the ultra-violet rays and these are not in focus upon its surface. Outside of the lens, the remedies for color aberration are to focus through a blue glass, to use a blue ground glass, or to wear 21 12 THE MOTION PICTURE blue spectacles. Another method is to know the specific correction for the lens used and to move the ground glass the proper distance toward the lens after focusing upon the yellow image. Fig. 16. Chromatic Aberration Within the lens, "the correction may be made by uniting two pieces of glass of different refractive powers, one lens being ground "positive," or thicker in the middle than in the edges, and the other one being ground "negative," or thinner in the middle than in the edges. Two of the surfaces have the same curvature and the two lenses when completed are cemented together, Fig. 17. Even the cheapest classes of lenses are thus made double, except in the smallest sizes and when of short focus. A rectilinear lens, composed of two single lenses, each of which is corrected for chromatic aberra- tion, would present a combination of glasses such as is shown in section in Fig. 18 or Fig. 19. Astigmatism. The meaning of this word is with no point. Its meaning as applied to a photographic lens is that the lens has not the ability to bring to a focus at a point all of the rays proceeding from a point in the subject. Thus a point in the subject becomes something else in the image. The bundle of rays passing from a point in the subject and through the stop opening takes the form Fig. 17. Achromatic Lens shown in Fig. 20. The best focus is obtained by placing the ground glass at the line b, where the point takes the form of a cross. When the ground glass is at the line a nearer the lens, the point takes the form of a short radial line, or ellipse, with its longer axis radial from PHOTOGRAPHY 13 the center of the image; when the ground glass is at the line c farther from the lens, the point takes the form of a short arc about the center Fig. 18. Fig. 19. Achromatic Rectilinear Lenses of the image, or of an approximate ellipse of which the shorter axis is radial and the longer axis is an arc instead of a straight line. The remedy for astigmatism lies in the construction of the lens, and lenses which are corrected for astigmatism are called !c \b Fig. 20. Bundle of Rays with Astigmatism anastigmats. Two, three, four, and even five pieces of glass are used sometimes in producing single lenses free from astigmatism, chromatism, and spherical aberration. Fig. 21 shows a single lens Fig. 21. Fig. 22. Anastigmatic Lens Combinations of four glasses. Fig. 22 shows the glasses of a aouble, or rectilinear, lens of two single lenses having eight glasses in all. The art of the lens maker is a delicate one. A lens should be bought and used by the photographer, and not tampered with. 23 14 THE MOTION PICTURE A good lens should be kept in a dust-proof case when not in use. It may be brushed with a soft camel's-hair brush and wiped with soft clean tissue paper to remove dust not a cotton or silk rag, which may carry grains of grit to scratch the surface of the glass. Shutters. When the camera is prepared for exposing a plate to an image, the lens stands as a window in the front of the camera. The purpose of the shutter is to close the lens window until the moment for exposure, then to open the lens and again to close it after sufficient amount of light has passed through to impress the image upon the sensitive plate. Cap. The simplest of shutters is the cap, which is a shallow box fitting closely over the front of the lens barrel. For exposures of several seconds or more in duration, the cap offers the most con- venient means, while for exposures of less than one-half second, the cap can hardly be removed and replaced quickly enough, and some sort of automatic opening and closing device should be used. Leaf. The leaf shutter consists of hinged leaves which meet and overlap to close the lens opening. They are forced open by a spring and forced closed by a spring. An exposure of as brief a space as T ^ second is feasible with the leaf shutter; and some shut- ters are advertised to make even shorter exposures. By the addition of an air piston, the closing of the shutter may be delayed until after the piston has completed a predetermined travel, thus giving an exposure longer than the shortest of which the shutter is capable. The usual "automatic" leaf shutter may be "set" before exposure to give an exposure of from one second to y^ second. The shutter may be adjusted also to hold the lens open until released. Exposures longer than one second may be made by the "time" adjustment, opening the shutter at the beginning of exposure and closing it after the proper lapse of time, as in the case of exposure with the cap. The leaf shutters usually work between the lenses, near the diaphragm. Curtain. The curtain shutter consists of two curtains on spring rollers inside the camera just behind the lens. When the shutter is adjusted for exposure, one of the curtains is in front of the lens; the other is above, rolled up. Upon release of the shutter, the lower curtain rolls down, opening the lens; after the desired lapse of time, the upper curtain unrolls and passes down, stopping over the lens and closing it. PHOTOGRAPHY 15 Focal Plane. The focal plane of the camera is the position of the image formed by the lens. When ready for an exposure, the sensitive plate is located in the focal plane. The focal-plane shutter, which is a curtain just in front of the plate, is so called because it is placed as near to the plate as possible and, therefore, near the focal plane of the camera. The curtain has a slit which may be adjusted in width or it has several slits of different widths. When released the curtain rolls without stopping, and the length of time during which the light is permitted to shine upon the plate is determined by the speed of the curtain and by the width of the slot. With a shutter of this type, exposures as short as -nj-Vir second may be given. The shutter is available equally for longer automatic exposures and for time exposures. Testing. An automatic shutter has a scale for setting the speed of the shutter, usually marked 1, 2, 5, 25, 100, meaning, respectively, 1 second, i second, ^ second, -^ second, and y^ second. The ex- posure given to the plate is not always true, however, to the value indicated by the scale of the shutter. The method of test is: Photograph with the automatic shutter at one of its settings an object moving at a known speed; then calculate the length of time of the exposure from a measurement of the amount of movement visible in the photograph. The distance moved in the photograph is to the distance moved by the object during the exposure as the focal length of the lens is to the distance of the lens from the object. When the distance moved by the object and the speed of the object is known, the time required to move through that distance may be known, and that is the actual exposure of the shutter for the speed setting under which the test was made. . A wheel driven at a constant and known speed may carry a mirror on its face near its edge, the mirror reflecting the light of the sun or of an arc lamp into the lens. In this case, the distance and focal length need not be measured; the angle of the arc which the revolving mirror makes upon the plate while the shutter is open will give the duration of the exposure for the shutter setting under which the test was made. Under test, a new fabulously high-priced leaf shutter showed an accuracy of only 60 per cent. Another cheap leaf shutter gave exactly the same length of exposure for its ^ marking and for its 16 THE MOTION PICTURE r ^ marking, the exposure being ^5- second for either of them. A fair shutter test easily made is as follows: With stop f/ 11 and shutter speed -%% expose a plate, and with stop f/64 and cap, time, or bulb exposure, give 1 and lj seconds as accurately as possible. These exposures are nearly equal, and when developed in the same tray or tank the plates should be alike. The speed markings of a new shutter may be accepted as cor- rect; the medium speeds ^ and -%j, which are use d most by the ama- teur, are likely to be nearly accurate. The shorter exposures are likely to be too long; the longer ones are likely to be too short. An old or second-hand shutter should be tested for speed before good work is attempted with it. Plate=Holder. For experimental work for the purpose of gain- ing a knowledge of photography sufficient for the making of motion pictures or good still pictures, glass dry plates should be used. Cut films or roll films may be adopted later, but the more reliable glass dry plate should be used by the beginner. The plate-holder has two draw slides, and when each is drawn there is revealed a set of clamps for holding a glass plate inside the holder. The handle, or edge, of each slide is white on one side and black on the other. In the dark room, by dim ruby light, place a glass plate in each side, with the film, or dull, side facing out, and replace the slides, white side out. The plate-holders should be numbered on each side, the first holder being 1 on one side and 2 on the other; the second holder being 3 on one side and 4 n the other, etc. When exposing plates, always expose first the No. 1 side of the first holder, or the No. 1 plate, then the No. 2 plate, then No. 3, etc. Upon returning to the dark room for development, the subjects upon each plate will be remembered by remembering the order of the exposures, and it is likely that only one exposure will have been made upon each plate. Without some system for exposing plates in order, it is possible that upon development one plate will show a ship sailing through a forest, and another plate will show nothing but the fog of an imperfect ruby lamp. The camera is so arranged that the ground glass may be removed and the plate in its holder substituted. The removal of the ground glass may be by actually taking away the frame which holds it, but the more common method in small cameras is to force the plate- 65 J3 i s o 5 O^o te.S^ PHOTOGRAPHY 17 holder into the camera in front of the ground-glass frame, the ground- glass frame being held by springs which yield to permit the plate- holder to enter. When the plate-holder is removed subsequently, the ground-glass frame automatically resumes its proper position for focusing. Darkroom. The darkroom is a room which is not merely dusky, but a room which has absolutely no white light. It may have red light until it is far from dark, hence "darkroom" is but a name. It must not have any light which will affect the sensitive plate. No daylight. Window's, doors, and transoms must be examined for cracks. After remaining in a darkroom for a few minutes, cracks will be seen which were not noticed at first. A bathroom at night makes a desirable darkroom for photographic operations. A mov- able platform across the tub offers a work table, and running water is convenient. A ruby lamp must be purchased. If a satisfactory screen is made for the window, such a dark room may be used during the day. No white light must get to the plate except through the lens during the interval of exposure. A little practice enables the photographer to load his plate-holders by touch alone, no light being needed. This enables plate-holders to be loaded in daytime in any closet by a little care in closing the cracks around the door. A convenient darkroom may be built of rough boards in any corner of any room, basement, attic, or barn, the cracks being care- fully closed by papering inside and outside. A developing shelf should be the height of the waist. If running water is desired in the darkroom, a sink should be convenient to the developing shelf, but running water in any but a very large darkroom is an objection rather than an advantage. In the wall back of the developing shelf a window should be cut into which a sash is fitted carrying a ruby glass. Outside of the darkroom, on a shelf or bracket, should be the lamp for furnishing the ruby light, so placed as to shine through the window. Shelves for chemicals, apparatus, and supplies are outside the darkroom. The darkroom contains nothing but a de- veloping shelf, a door, and a window provided with removable colored glass. Dishwashing, and other processes not necessarily darkroom processes, may be done elsewhere. Routine of Camera Operation. Select the view. Open lens. Open stop. Focus and manipulate the camera until you have upon 27 18 THE MOTION PICTURE the ground glass the image you want, no more, no less. Decide upon the stop opening to be used and the length of exposure to be given. Set stop opening. Close lens. Adjust shutter to selected speed setting. Insert plate-holder. Draw dark slide of plate-holder. Re- lease automatic shutter or otherwise make the exposure. Replace dark slide in plate-holder, black out. Remove plate-holder from camera. Practice this routine without plates in the holders, or without drawing the dark slide from the plate-holder, until entirely familiar with all of the steps. Many plates are spoiled by drawing the dark slide before closing the lens, or by failure to draw the dark slide at all. PRODUCING THE IMAGE The picture is made upon the ground glass of the camera. If the photographer has the patience and skill, or the good luck as an amateur, to secure such an arrangement of his subject upon the ground glass as makes a good picture there, then the mechanical and chemical processes which follow will merely record that picture and will produce a pleasing photograph unless the record should be spoiled by accident. The view selected to be photographed often is forced upon the photographer. He must produce a picture of this house, or that bridge, or of the children of the family. The motion-picture camera man must photograph the set stage or such other subject as the producer in charge may direct. Yet the control of the image in nearly every instance is so completely in the hands of the camera operator that the resulting picture is better or worse as he is careful or careless, and according as he understands the possibilities of his camera to control the arrangement of the details of his subject. All of this control of the resulting picture, after the voluntary or enforced selection of the principal subject, must be exercised before the exposure of the sensitive plate or film is made by the operation of the lens shutter. After the lens has been opened upon the subject, transmitting the light of the image to the sensitive plate, no further change can be made in the picture. The making of the picture, that is, the making upon the ground glass the image which is to be recorded to become the finished photo- graph, may be divided into seven points for consideration und study, as follows: 28 PHOTOGRAPHY 19 (1) The selection of the principal object to be photographed. (2) The selection of a background or setting for the principal object. (3) The lighting or direction of light falling upon the subject as a whole. (4) The size of the principal object in the image. (5) The composition and balancing of principal and subordi- nate objects in the image. (6) The prominence of the background. (7) The avoidance of disagreeable distortions in the image. Principal Object. The total task of photographing usually is the making of a photograph which may be used to record some one object, such as a house, a tree, a flower, a person, or an animal. Sometimes it is merely "a pretty scene," but in this case the pho- tographer should decide upon some object of the scene to form the principal object of the picture. He should give such prominence to some object that the resulting photograph will be in substance a pic- ture of that principal object, yet will embody in its background or scenic setting the "pretty scene" which it was desired to photograph. Right at the beginning, and in the most fundamental of all of the principles of picture making, the camera operator has the power to control the image, to make or spoil the picture, even though com- manded by an outside influence as to his general subject. Whether he is inspired by the beauty of a scene to make a photograph of it, or whether he is commanded by a companion or by an employer to make a photograph of it, he still has the power to make some object a principal object, to hold other objects subordinate to it, and to mold the whole into an arrangement in the image on his ground glass which will result in a photograph worthy the name of a picture when finished. Each picture must have a principal object or it is at best only a photographic memorandum. Background. In portrait work in a studio, the backgrounds are painted as desired, and brought in or carried out, and turned and placed as needed. And for scenic work it is almost the same. Suppose that it is commanded that a photograph be made of a rose- bush in blossom in the front yard of a house. If the house would form a desirable background, set up the camera at the front fence. If the front fence would form a desirable background, photograph 20 THE MOTION PICTURE the rosebush from the house. If either side fence is better, place the camera at the opposite side of the yard. If none of the surround- ings are pleasing as background objects, there is still the possibility of viewing the bush from above so that the grass of the lawn, and not any fence, house, or other object is included as a background. This view may be had from the top of a stepladder, from an upper window of the house, or even from the height of the tripod above a porch floor. With some of these background arrangements surely the resulting picture will be better than with others. Get the best one, just to show that you are master of the camera, even though some one else dictates what your principal object shall be. When photographing persons or animals, the "principal object" usually may be brought to a suitable background. When photo- graphing a house, the inclusion in the image upon the ground glass of a little more of the foreground, or of a little of one of the houses standing at one side of the "principal object," or of a tree standing near, partakes of the fundamental principle of the selection of a back- ground and gives the camera operator some power to make his image nearer to a picture and farther from the memorandum type of photograph. Lighting. With immovable objects, such as trees, houses, and rosebushes, illuminated by the sun, the photographer has two methods of controlling his lighting, both of which consist merely in taking advantage of natural conditions by the selection of the proper time for making the exposure. The sunlight falls upon the object at dif- ferent angles and in different directions at different hours of the day. Whether the object is photographed in- the early morning, in the late morning, at noon, or in the afternoon is usually within the con- trol of the photographer, and it makes a difference in the pictorial value of the photograph. Few landscapes are pretty at noon, with the shadow exactly under each tree and bush; they are far better between two o'clock and five o'clock in the afternoon. The horizontal rays of sunlight become objectionable again in the late afternoon. The second method of control for immovable objects is the selec- tion of an overcast or hazy day in preference to a day of direct sun- light. Usually the direct sunlight, with sharp shadows is preferable, but here again the operator has control of the image in his hands. Size of Object. The size of the principal object is controlled by 30 PHOTOGRAPHY 21 the distance from the camera to the object and by the focal length of the lens. The nearer the camera is carried to the object to be pho- tographed, the larger will be the image of that object upon the ground glass. The longer the focal length of the lens used, the larger will be the image upon the ground glass. The image of the main object, therefore, may be enlarged by using one of the lenses alone instead of both of them double. Composition and Balance. By the terms composition and balance reference is made to the many relations which exist among the masses of light and shade among the lines of the image. The rules are so numerous that all of them cannot be followed at all times, and many of them apply only to specific instances of subject arrange- ment. A few of the more general rules may be kept in mind when arranging the image upon the ground glass. A profile portrait shows on one side the light face against the darker portion of the background, and on the other side the dark hair against the lighter portion of the background. Each side of the picture has its lights and its shadows. A landscape, even the picture of a building, should bear the same analysis. A balanced picture should have a principal shadow, and some minor shadows. It should have a principal high light and some minor high lights. With the principal shadow and the minor high lights on one side of the image and the principal high light and minor shadows on the other side, it is likely that an approximate balance will be obtained. For example: a heavy mass of foliage is at the lower right, as a near bush or tree; a few scattered masses are at the middle left and upper left, as distant bushes or trees; a roadway or stream runs from lower left to upper right, showing a large light spot at lower left and smaller light spots at upper right; the large light is a little higher or a little lower than the large shadow, not dead level that a line connecting them would be parallel to the margin. That sounds like a coldly critical analysis suitable for producing a stiff and formal picture, yet a scene sought out in nature and photographed from a viewpoint care- fully selected to secure this arrangement of lights and shadows will rank above a hand-camera snapshot and will repay the amateur's effort. In a water scene, a ship at anchor may be photographed from the pier with another pier in the background. Place the dark hull of the ship near the lower edge of the picture and at the right of the 31 22 THE MOTION PICTURE middle line; place the distant pier above the center on the left of the picture. The masts of the ship cut up into the upper right corner and break up the sea and sky into minor high lights. The major high light is the unbroken sea at the left of the ship, lower left corner of the picture. Strictly parallel lines are objectionable in a picture unless they are parts of an object and unavoidable, as the masts of a ship. Any line parallel to the margin of the plate is objectionable except the side lines of buildings, which are unavoidable. An imaginary line joining two high lights or two shadows should not be parallel to an edge of the plate, nor should an imaginary line from the principal shadow mass to the principal high light be parallel to any edge of the plate if it can be avoided. The horizon line requires care in this detail. Horizon Line. The placing of the horizon line has much in- fluence in the composition and balance of the picture. Care must be taken that the horizon line does not cross the principal object at an undesirable point, nor should the apparent horizon divide the picture exactly in the middle. Where a hillside is included in the landscape, it may be made to give an inclined or irregular line for the horizon. Where a level horizon is unavoidable, it should be broken if possible by the objects of the picture. Point of View. The point of view is the location of the camera whence the image is made. Changing the point of view is the most powerful means which the camera operator has for arranging and controlling his image. The selection of the background depends almost solely upon the point of view chosen. The size of the prin- cipal object is largely controlled by the choice of the point of view, while the composition and balance are almost wholly controlled by the selection of the point of view, together with the selection of the lens length. Prominence of Background. As a rule, the image may be separated into principal object and background, even though the background or setting of the principal object be really the more important portion of the picture, and the portion primarily desired. The relative size of the principal object and its associated background objects may be controlled by the lens length. With the double lens, focus upon a view containing a near tree as a principal object. Note the size of the distant trees. Remove the front lens cell, move PHOTOGRAPHY 23 the camera back to twice the distance from the principal tree, and focus again. By the change of the lens and the change of the point of view, the principal tree will be the same size as before; note that the distant trees are much larger than before, thus giving greater prominence to the objects of the background. Also, by the use of the longer focus of the single lens, less of the horizon is included in the image, and less of the surrounding landscape is shown as a background to the principal tree, that which is included in the image being shown in larger size. If the front and back cells of the lens Fig. 23. Perspective Distortion are different in length, the front cell alone will give still more prom- inence to the background objects, a greater extension of bellows and a still more distant viewpoint being required to keep the principal object at the original chosen size. When it is impossible to secure a point of view near enough to the principal object to secure a large image, the longest lens will give the largest possible image. In the case of a portrait, the background is entirely unimportant in detail, and is most satisfactory when shown merely as a blurred surface of light and shade. This is effected by opening the diaphragm to its largest stop size, then bringing theJace of the portrait to a sharp 24 THF MOTION PICTURE ocus. The background will be blurred because it is "out of focus." Out-of-door portraiture profits by the same rule, and the rule applies generally where the picture is to be a photograph of a specific object and the background is not a part of the object. Where both fore- ground and background are required to be sharp, a small stop opening must be used to secure the result. Distortions. Usually, any distortion of the image caused by the lens is objectionable. Blurring the background in portraiture and similar pictures by using the shallow field incidental to the large stop opening is in itself a form of distortion which is made to serve a useful purpose and is an aid to the operator in the control of his image. Barrel distortion and pin-cushion distortion, which have already been discussed, should be avoided as far as possible, particularly in architectural subjects. Perspective distortion will be observed if the camera does not stand level upon its tripod. In landscape views, such distortion Fig. 24. Camera 'v?th S ving Back Fig. 25. Camera with Rising Front in Use in Use usually is negligible. In architecture it is ludicrous, Fig. 23. The remedy is to keep the ground glass vertical, or nearly so. This is done by the swing back and by the rising front. Swing Back. When the back of the camera, carrying the ground glass and the plate-holder, is pivoted or hinged, the body of the camera may be tilted to bring the desired scene upon the ground glass, and the swinging back of the camera then may be adjusted to bring the ground glass vertical or nearly so, Fig. 24. By this adjustment, the perspective distortion will be corrected, but the focus is more 34 PHOTOGRAPHY 25 difficult and a smaller stop opening will be required to give a sharp focus over the entire plate. Rising Front. With the camera placed about level, more of the sky or more of the foreground may be included upon the plate by raising or lowering the lens in the front of the camera, Fig. 25. This avoids perspective distortion, but the amount of adjustment thus obtainable is somewhat limited. RECORDING THE IMAGE The recording of the image consists of two processes expos- ing the sensitive plate and developing the exposed plate into a negative. Dry Plates. The art of the chemist is brought into use in record- ing the image of the lens. The known substance most sensitive to light is finely divided nitrate of silver suspended in gelatine. The manufacture of this substance is not attempted by the photographer. A thin skin of the prepared gelatine is spread upon glass plates and dried. The plates thus made are sold under the name of photo- graphic dry plates. These are bought by the photographer in light- proof sealed packages and loaded into plate-holders in the darkroom. Films. Flexible transparent celluloid films coated with the prepared gelatine are used instead of the glass, if desired, and may be had for pictures up to a 5 by 7 size, either in packets of cut films or in rolls of proper width on which exposures may be made one after another. In motion-picture work, the celluloid film is a necessity and it is used universally in commercial motography. Exposure. When the plate-holder is inserted in the camera, the lens closed, and the dark slide withdrawn, the lens is opened just long enough to permit a sufficient amount of light to pass through the lens to affect the sensitive silver of the dry plate neither too much, nor too little. This process of administering to the plate the proper dose of light in the form of the image is called exposing the plalc. The greatest problem in photographing any subject is the best arrangement of the image upon the ground glass, and the next greatest is the determination of how long a time, in seconds or frac- tions of a second, to permit the light to flow through the lens to impress the image properly upon the sensitive plate. The amount of light from a given subject which falls upon 35 26 THE MOTION PICTURE the sensitive plate to impress the image depends upon the size of the stop opening and the length of time during which the lens is left open for the exposure. Light flowing through the stop opening is just like water flowing through a hole. If you increase the size of the hole, the bucket will be filled with water in less time, and in direct proportion to the change of the size of the hole. Double-size hole, half the time to fill the bucket. Half-size hole, double time to fill the bucket. A hole ten times the size will fill the bucket in one-tenth the time. This rule holds strictly true in the case of the photographic exposure. Increase the size of the stop opening and the light passes through faster, giving the plate sufficient light in a shorter time. A larger plate requires a greater quantity of light because there is more surface to be worked upon. The light spreads from the lens, and the farther back from the lens the light must go to reach the plate, the more it spreads out and the weaker it becomes. The lens length has a direct influence in the strength of light upon a plate from a given subject through a given opening or, to state the same rule differently, the lens length has a direct influence in determining the size of stop opening which must be used to effect the same strength of light upon a plate from a given subject. Stop Numbers. A plan of numbering stops according to the size of the opening has been devised which removes the actual focal length of the lens from the calculation of the strength of the light upon the plate, by including the focal length of the lens in the deter- mination of the stop number. There are in common use in America two systems of stop numbers the focal-factor system and a modifi- cation called the uniform system. The plan used in the focal factor system consists of numbering the stops in fractions, as 1/8, 1/10, 1/32 of the focal length of the lens; these are written //8, //16, //32, etc., or F/8, F/W, F/32, etc., or /-8, /-16, /-32, etc., or /:8, /:!(>, /:32, etc. The stop number //16 means that the diameter of the stop opening is 1/16 the focal length of the lens. An //1G stop for a 4-inch lens is 1/4 inch in diameter. An //1 6 stop for an 8-inch lens is 1/2 inch in diameter, giving four times the area of the stop open- ing, giving four times the quantity of light, but since the light goes twice as far before it reaches the ground glass or sensitive plate it will spread over four times the area and, therefore, will be of the PHOTOGRAPHY 27 same strength, or intensity, on the plate with the 1/2-inch stop //16 of the 8-inch lens as with the 1/4-inch stop //16 of the 4-inch lens. This is of great convenience in writing of exposure timing, because by the use of the focal-factor system of stops all the rules given for exposure will be true for cameras of all sizes and for lenses of all lengths of focus. In both systems each stop number requires either double or half the exposure of the next stop number, the stops being alike at //16 and No. 16. If the stop numbers on a scale are 4, 8, 16, 32, 64, 128, 256, it is "U. S." or uniform system. If the stop numbers on a scale are 8, 11, 16, 22, 32, 45, 64, it is focal-factor system. In either case, as the numbers increase each number requires double the time of exposure required for the preceding or next smaller number. In any lens, the largest opening possible may not be an even stop number, and this first marking of the scale may vary from the "double time" rule. Thus, if a lens will work with an opening of //7, its scale will be marked 7, 8, 11, 16, etc., if for the focal- factor system; or 3, 4, 8, 16, etc., if for the "U. S." system. In Table I the numbers in the two systems are compared. TABLE I Equivalent Stop Numbers in Focal-Factor and Uniform Systems f/2 f/3.5 f/4 f/4.5 f/5 f/5.6 f/6.3 f/7 No. i No.| No. 1 No. It No. H No. 2 No. 1\ No. 3 *f/8 *f/ll *f/16 *f/22 *f/32 *f/45 f/64 f/90 No. 4 No. 8 No. 16 No. 32 No. 64 No. 128 No. 256 No. 512 *The stop numbers in the two systems which are most commonly met and used. Plate Speed. Some plates are coated with a gelatine film which is more sensitive to light than others. As a standard, plates such as Seeds 26x, Stanley, Hammer Fast, Cramer Instantaneous Iso, and Standard Extra may be taken as most suitable in speed for amateur work. These plates list 130 on the Watkins scale of plate speeds. A faster class of plates comprises Cramer Crown, Hammer Extra Fast, Seed 27, and Kodak and Premo Films. These list at 180 on the Watkins scale and require only three-quarters the exposure to impress the image as fully as upon a plate of the 130 class. 37 28 THE MOTION PICTURE Light Intensity. In filling a bucket with water running through an opening, the pressure which is behind the water will influence the rate of flow and will influence the time required to fill the bucket. The intensity of the light which illuminates the subject and the nature of the subject itself are the two elements which influence the rate of flow of light through the lens opening. On a dark day the light does not pour through the small stop opening as fast as on a day of blinding sunlight. Even in the same bright sunlight, the quantity of light sent to the camera from a dark green tree is less than the quantity sent from the white sails of a ship. One considera- tion of the nature of the subject also is its distance from the camera. If the average amateur photographer were asked the exposure for a summer landscape, he would probably say, carelessly, //1 6 and 1/25 of a second. That is the hand-camera way and gives but twenty good negatives out of a thousand exposures. The intensity of light depends upon the height of the sun above the horizon, which varies with every day of the year and with every hour of the day. With a clear sky and an average subject, Table II gives in seconds the proper exposure (Watkins 130 list plate) for //1 6 stop for each hour of the year, by months, for the latitude of the northern portion of the United States. In the southern portion of the United States, three-quarters of this exposure is sufficient; and on the equator, probably one- half is sufficient, and the May- June-July column may be used all the year around, with the 5 A. M. and 7 P. M. figures omitted. For a hazy day good daylight but cloudy enough to obscure the sun give double the exposure as a correction for the clouds. On a heavily overcast, gloomy day, give four times the exposure as a correction for clouds. Nature of Subject The nature of the subject to be photographed has an influence even greater than the time of day or condition of the clouds. For pictures in the middle of the day, a glance at the table shows that the midwinter exposure with sun is but little more than double the midsummer exposure with sun. The exposure for cloudy days is only twice or four times that for sunny days. But the correction for the nature of the subject even with outdoor subjects may be two hundred times as much for one subject as for another. The following corrections may be applied to Table II to com- 38 PHOTOGRAPHY 29 TABLE II Day and Hour Exposure Chart A. M. P. M. Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec. 5 A.M. 1 6 A.M. 1 1/2 1/5 1/2 1 7 A.M. 2 1/2 1/5 1/10 1/10 1/10 1/5 1/2 2 2 8 A.M. 1/2 1/5 1/10 1/10 1/10 1/10 1/10 1/5 1/2 1/2 9 A.M. 1/5 1/10 1/10 1/15 1/15 1/15 1/10 1/10 1/5 1/5 10 A.M. to 2 P.M. 1/10 1/15 1/15 1/25 1/25 1/25 1/15 1/15 1/10 1/10 3 P.M. 1/5 1/10 1/10 1/15 1/25 1/25 1/15 1/10 1/5 1/5 4 P.M. 1/2 1/5 1/10 1/10 1/15 1/15 1/10 1/5 1/2 1/2 5 P.M. 2 1/2 1/5 1/10 1/10 1/10 1/5 1/2 2 2 6 P.M. 1 1/2 1/5 1/2 1 7 P.M. 1 pensate for the difference in the character of the subject of different images. 1/20 exposure for sky and clouds, where the foreground objects do not form a part of the picture. 1/10 exposure for sea and sky, ships at a distance at sea, views at a distance across the water. 1/4 exposure for open views, where the important portion of the view is in the distance and the foreground is unimportant. 1/2 exposure for very light objects of importance in the foreground. Exposure time given in the table is suitable when the important objects of the image are 20 to 100 feet from the camera and are neither white nor black, neither very light nor very dark. Twice the exposure time given in the table for objects nearer than 20 feet, or for dark objects of importance in the foreground of the image. Four times the exposure time for portraits in shade of heavy foliage, and for dark objects nearer than 20 feet. Sixteen times the exposure time for pictures in dense woods where side light as well as top light is obstructed by the foliage of the trees-. Near sunset, five times the exposure in order to compensate for the yellow color of the sunset light. Interiors, if very well lighted by windows and with light walls, 100 times the table values. Interiors, if not well lighted, 500 to 5,000 times. When the sun is in front of the camera so that the shady side of the subject is being photographed, the exposure should be doubled. 39 30 THE MOTION PICTURE Calculation of Exposure by Table. To calculate an exposure requires that the proper //16 time for average plate and subject be taken from Table II. If the subject is an average one and the sum- mer day is bright, then there is no correction to be applied, the stop is set to //1 6, and the figure taken from the table is set upon the automatic shutter and the exposure is made. A few exceptions may be studied. The summer hotel presents from across the valley a view which the visitor wishes to take with him. At one point in the road a group of trees between the road and the hotel obscures the hotel, but by taking a viewpoint farther along the hotel is free from the ob- struction and the group of trees at one side of the middle of the image balances the hotel at the other side. The trees being nearer and larger are the "main object" of the com- position, but the building is the more important. It is painted white. Trees behind it show its outline definitely, and both the trees behind and the "main object" group of nearer trees break the horizon line. The horizon line is placed high three-fifths from the bottom and two-fifths from the top line of the picture. If possible, the cam- era is so positioned by its selection of viewpoint that some small object breaks the foreground on the side opposite the "main object" group of trees. The ex- posure is: Summer, 2 P. M., by Table II, 1/25 second; important portion of the view is in the distance and foreground unimportant, correction 1/4; the exposure should be 1/100 second at //1G, but better 1/25 second at jf/32 to increase the sharpness of the distant object. In a light subject, give less rather than more time than given in the table. Further along, the visitor passes through a wood and notes a clump of pretty ferns. The table says 1/25 second; correction for deep wood, 16; correction for dark color (green) of ferns, and near the camera, to have the image of the ferns large, 4. Time 64/25 or Fig. 26. Watkins Exposure Meter 40 PHOTOGRAPHY 31 1\ seconds at //16. In a dark subject, give too much rather than too little time by the table. Exposure Meters. The exposure meter is a device for measur- ing the strength of the light which falls upon the subject. It takes the place of Table II and of the correction for the clouds. Two types of exposure meters in general use are the Watkins, Fig. 26, and the Wynne, Fig. 27. The principle of both meters is the same. A disk of paper which is discolored rapidly by light is movable behind a slot, and beside the slot are bits of color which the paper matches in the course of its discoloration under the influence of light. The more intense the light, the more rapidly does the exposed bit of the paper disk become discolored, and the sooner does it reach a tint which matches one of the bits of color adja- cent to the slot. The time required to match the darker color is taken as ac- tinic value of the light. An exposure- calculating disk forms a part of each meter. Upon and near the calculating disk are sets of figures for (a) the ac- tinic or meter value of the light, as noted in the number of seconds which is taken by the paper to discolor to match the dark standard tint; (6) the speed of the plate which is to be used in the ex- posure; (c) the diaphragm stop; and (d) the required exposure in seconds or fraction of a second. The difference between the two meters is found in the cal- culating device. In the Watkins, the stop number is set opposite the plate number; then opposite the time required for the paper to darken is found the time required to impress the image upon the plate, that is, the exposure time, to which the correction for the nature of the subject must be applied. This appears to be the more convenient meter for the amateur either with hand camera or tripod. In the Wynne, the time required by the paper to darken is set opposite the speed number of the plate; then opposite the stop number is read the required exposure for a standard subject, to which the cor- Fig. 27. W iVynne Exposure 41 32 THE MOTION PICTURE rection for the nature of the subject must be applied. This is the more convenient for the motion-picture camera operator because of an exposure limitation in the motion-picture art. The Wynne meter is preferred by many fixed camera operators who have be- come familiar with it. Full instructions for use accompany either meter when purchased. There are also upon the market many exposure meters, so- called, which are but calculating devices for combining the date table with the cloud correction, subject correction, stop number, and plate speed. Perhaps, when facility has been acquired with one of them, it would be found convenient. Exposures with Single Lens. When the front lens of a double lens is removed, for the purpose of obtaining a larger image, or to increase the prominence of the background, the focal length of the lens has been changed, without changing the markings of the diaphragm scale; these markings, therefore, are not correct for the single lens. To obviate this, some lenses have two or three sets of markings on the diaphragm scale, one for the double lens and one for a single lens if both singles be of the same focal length, while if the singles be of different focal lengths there may be three mark- ings, one for the double lens and one for each of the singles. Where the singles are of the same focal length, the exposure time for a single lens will be four times that for the double lens with the same stop setting, to compensate for the difference in focal length between double and single. Where the singles are of different focal lengths, the exposure for the short single will be three times that for the double lens, and the exposure for the longer single will be six times that for the double lens. Duplicate Exposures. When much is in doubt, and upon sub- jects which cannot be photographed again, two exposures may be made, using two plates, and giving different lengths of exposure. If the range of exposure is such that one plate has ten times the exposure of the other both may give good negatives, whereas, if this ratio is increased to twenty-to-one, disappointment may be met by finding one plate under-exposed and the other over-exposed. As an over-exposure is a better printing proposition than an under exposure, a good rule for duplicate exposures is as follows: 42 8 IS PHOTOGRAPHY 33 Estimate the exposure, then give one plate half the estimate and the other plate five times the estimate. Development. The subject having been selected and arraned upon the ground glass, and the sensitive plate having been inserted and exposed by setting the diaphragm as determined by judgment of the image, and setting and releasing the shutter as determined by meter or Table II and judgment of the nature of the subject, the field work for that particular plate is finished. Other plates may be exposed before developing the first, and development may be done either immediately after exposure or after a lapse of a few days or weeks. The exposed plate is still sensitive to light and must be kept in the holder with the slide closed until removed in the darkroom. As the plate itself bears no evidence whatever of having been ex- posed, it is impossible to tell an exposed plate from an unexposed one except by applying a developer, which brings out the image if exposed and spoils the plate if unexposed. The indication in the field or in the darkroom that a plate has been exposed is the slide of the holder, which should have its white side out for an unexposed plate and its black side out for an exposed plate. The plate when exposed is said to contain a latent image, because the invisible image may be brought out and made visible by a process called develop- ment. This is done by soaking the plate in a chemical solution which turns the nitrate of silver black only where it has been struck by the light but does not affect it otherwise. Negative Image. The gelatine film of the plate when developed shows the image which was seen upon the ground glass, but with its lights and shadows reversed. A black sky is seen above a white grassy foreground; a black brook flows under white trees; the figures in the picture are black of face and have white hair. Developers. There are many different developers on the market, each with its claims. The selection is a matter of personal opinion, and in the writer's opinion there is no developer as good as pyro and soda, although it stains the fingers if the operator is careless about slopping around in the darkroom. Hydroquinone and metol developer is second choice, and this does not stain the fingers. For the first few plates to be developed, the amateur should buy a ready-mixed developer, either liquid or powder form, to avoid 43 34 THE MOTION PICTURE the possibility of losing all of the first batch of plates through a error in compounding the developing solutions, and to avoid plac ing a blame upon improper exposure when the actual fault is an error in compounding the developer. Formulas for developers will be given after the processes of development with ready-mixed de- velopers have been studied. Trays and Covers. The developing tray is a flat dish having a flat bottom so the glass plate will lie close upon the bottom of the tray. Half a dozen should be available, each the proper size for one plates. Covers for the trays should be light tight. A good cover is a developing tray of such size that, when turned over the smaller developing tray, it will come down to the developing table or shelf all around the edge. Almost as good but not so convenient a cover is a folded paper larger than a tray laid across the top of the tray and a flat weight, such as a small piece of wood larger than the developing tray,which is laid upon the paper and holds it close to the top of the tray all around the edge. A measuring glass and a thermometer will be needed. Ruby Lamp. A "safe" light is one which may shine upon a sensitive plate without spoiling the plate. Such a light is a theoretical proposition. I To determine whether your ruby lamp is safe, cover half a plate and expose for five minutes to the direct rays of the lamp two feet away. Then develop. If the half exposed to the light is fogged, the lamp is not entirely safe, although it may be good enough. Very few lights are safe which are strong enough to be of any use. It is quite possible to use an unsafe lamp without spoil- ing plates; that is the object of the tray covers. The writer has de- veloped many plates and films when he did not have a red lamp at all. Sight Development. In preparation for development, set a tray 18 inches or 2 feet from the red lamp. Beside it place the meas- uring glass or a drinking glass containing four ounces for 4 by 5 or six ounces for 5 by 7 of developer at 65 degrees by the ther- mometer, ready to pour upon the plate to be developed. Have a cover for the developing tray handy. A foot or more away, beyond the reach of splashes, place the plate-holder containing the exposed plate to be developed. A pan of water, larger than the plate, is convenient for rinsing the plate, and outside of the darkroom but near it is a developing tray containing half an inch in depth of a fixing 44 PHOTOGRAPHY 35 solution made of four ounces of hyposulphite of soda dissolved in a pint of water. All of this in full white light, that no mistakes may occur. A clock or watch in the darkroom should be so placed that it may be read by the red light. Close the darkroom door and shut off all light but the red. When the eyes have become .^accus- tomed to the weak red light, open the plate-holder, lift the exposed plate by the edges, place it in the developing tray film side up, glance at the clock, pour on all of the developer, making half an inch deep over the plate and wait. If the plate is a landscape, soon one part of it will begin to look gray; this is the sky coming up under the action of the developer. This should be seen in from half a minute to one minute after the developer is poured on. Soon the outlines of objects in the foreground will be seen, and by the end of two minutes the picture will be completely visible. This is not half enough development. The picture will begin to fade away, to sink into the film, and the whole plate will get dark on the surface. When the picture has had five or six minutes and seems completely spoiled, lift the plate by the edges and see whether the heavier and darker spots have come through upon the back of the plate. If the picture is visible upon the back, through the glass of the plate, it is likely that the negative is very good. Rinse in the pan of clean water for fifteen seconds or more, that the developer may be washed out of the film as well as washed off the surface, then open the darkroom door and place the developed plate in the tray of hypo outside; wash the hands free from hypo before going back into the darkroom. At this time, the negative will show the black image upon a milky film. When held to the light, the plate is opaque and the image blurred. After five minutes in the fixing bath the "milk" of the film should be fading rapidly, and ultimately there will be left only clear glass, easily seen through, with the image sharp and black. This is sight development. The plate is watched all the time, and when the image is strong enough, usually judged by its being visible through the back of the plate, the plate is taken from the developer, rinsed, and placed in the hypo fixing bath. For this method of develop- ment, strong, medium, and weak developers are used. Plates which seem slow in coming up are put in strong developer, while plates which come too fast are placed in weak developer. Few people understand sight development, and it requires an experienced eye 45 36 THE MOTION PICTURE to decide when the development should be stopped. It is not a good method for an amateur, but it should be used for the first plate, that the amateur may see what the process of development really is, even though the first plate be spoiled in learning. Factorial Development. This system is a modification of the sight development system which brings development within the range of the amateur. The developer should be mixed according to a standard formula, it should be at 65 degrees by the thermometer, and the factor should be known. With ready-mixed developers, the factor usually is printed on the wrapper of the package. . A plate properly exposed will show gray in the sky in one-half minute and be fully developed in six minutes. A plate which has had a little too much exposure will be fully developed in five minutes, but it will show its first gray in twenty-five seconds from the time the developer is poured on. A much over-exposed plate will be fully developed perhaps in three minutes, but it will show its first gray in fifteen seconds. An under-exposed plate may need twelve minutes of development, because with the less exposure the image builds up more slowly and also appears at first more slowly, taking one minute to show its first gray. It has been noted that the total time of development required is always with pyro developer about twelve times the time required for the plate to show its first gray, hence, we have this factorial development system with this rule : Have the developer at 65 degrees, and notice the time from pour- ing it upon the plate until the first gray is shown. Cover up the tray and wait until it has devoloped twelve times that long; then wash it and place it in the fixing bath. This method protects the plate from the red light except for the first minute, and even this may be reduced by holding the tray cover between the tray and the light and only removing the cover for a second every five or ten seconds until the first gray is noticed. This is a thoroughly practical system for amateurs. Two or more plates may be started at once in different trays, and still others started while these are developing. The time for taking out of the developer may be written on a slip of paper placed on top of each tray cover. Tank Development. By the name, this is a large tank, capable of holding several plates, or several dozen plates, and filled with developer. The developer is at 65 degrees. The plates are put in, 46 PHOTOGRAPHY 37 left twenty minutes, taken out, rinsed, and placed in the fixing bath. This is a simple method used by professionals and suitable for amateurs. It merely requires care that the developer is standard strength and standard temperature. In the amateur's darkroom, this tank method operates as fol- lows: Prepare developer according to tank formula; by red light place a plate in a tray and fill the tray with tank developer at 65 degrees; wait twenty minutes; remove plate, wash and fix in the hypo bath. In hot weather, the trays should be cooled to 65 degrees or they will heat the developer; in cold weather it may be necessary to warm them to 65 degrees. This method sometimes is called the time and temperature method. With a few plates to develop it is not economical of time nor of developer but the results will average higher in quality than with either sight or factorial method of de- velopment in the hands of an amateur. Developing without the Red Lamp. To develop without the red lamp is merely a matter of time and temperature, and handling the plates by touch. By white light, pour the developer into the tray (65 degrees); have the cover at one side and the plate-holder at the other. Put out the light and in darkness remove the plate from the holder, place it in the tray of developer, and place the cover on the tray. Light the white light, look at the watch, wait twenty minutes, remove the plate in white light, rinse quickly and thoroughly and place in the fixing bath. The secret of this process is that white light followed quickly by a fixing bath does not injure the plate. Washing before Fixing. The plates should be washed before fixing in order to keep the developer out of the fixing bath. The negatives will become stained in the fixing bath if this is not done. Fixing. The milky silver of the plate must all be removed. To insure this, the plate should be allowed to remain in the fixing bath after the milky appearance is gone for a time half as long as was required to remove the milky appearance. Fixing after Washing. The hyposulphite of soda must be thoroughly washed out of the film or the negative will spoil with age. An hour in running water, or soaking for fifteen minutes each in six changes of water should insure the complete removal of the hypo. The plate then is set on edge or placed in a rack to dry in a place where dust will not settle upon its sticky wet surface. 47 38 THE MOTION PICTURE Developing Formulas. A convenient method for compounding developers is to open an ounce box of pyro or other developing agent and weigh it all out into quantities each of which will make one pint of developing solution ready for use. These quantities may be wrapped in waxed paper and packed in an air-tight can, bottle, or box. Similar powders of soda may be made up, and when developer is wanted it is necessary only to take one powder from each can and dissolve in a pint of water. Pyro Developer: First powder 14 grains pyro Second powder 80 grains sulphite of soda, anhydrous 55 grains carbonate of soda, anhydrous For sight or factorial development, take one each of the powders and 16 ounces of water. Temperature 65; factor 12. A normal exposure should develop for about six minutes. For tank, or "time and temperature" development, take one each of the powders and 36 ounces of water. Temperature, 65; time 20 minutes. Pyro developer can be used only once except for sight develop- ment, and even then it is not advised. It must be used within a few minutes after dissolving but will keep indefinitely before dissolving. Hydro-Metol Developer: First powder 14 grains metol 14 grains hydroquinone Second powder 104 grains sulphite of soda, anhydrous 104 grains carbonate of soda, anhydrous Dissolve separately one each of the powders in 8 ounces of water; pour together, making 16 ounces of developer for sight or factorial development. Temperature 65; factor 15. For tank, add water to make 36 ounces of developer; tempera- ture 65; time 20 minutes. Hydro-metol developer may be used repeatedly for sight devel- opment, but works more slowly after the first use. Plain Hypo Fixing Bath: 4 ounces hypo crystals 16 ounces water 48 PHOTOGRAPHY 39 This bath will keep indefinitely until used, but will not keep after it has been used. It may be used for several plates but works more slowly after the first. Wash the plates well before putting them into the plain hypo bath, for a little developer in the plain hypo will stain the plates if they are left in the bath long. Acid Hypo Fixing Bath: 16 ounces water 4 ounces hyposulphite of soda, crystals 80 grains sulphite of soda, anhydrous 60 grains powdered alum 1 dram citric acid Dissolve completely the hyposulphite and the sulphite before add- ing the alum and citric acid, or the bath will be milky and less efficient. The acid fixing bath will keep before and after using. It may be used repeatedly as long as it will dissolve the silver from the film, but it works more slowly after the first use. It is less likely to stain the negative from developer, but will do so if too much developer gets into it, and after it becomes weakened with repeated use. It should not be used after having become discolored with developer, for fear of stains upon the negative. Removing Pyro Stains. Negatives stained with pyro may be cleared after washing and drying in the usual way by immersing in a bath of 3 ounces iron sulphate (copperas) 16 ounces water \ ounce sulphuric acid 1 ounce powdered alum Wash and dry as after fixing. The pyro negative has an olive green natural color which adds much to its good printing qualities. This color is not a stain, and should not be removed. The copperas clearing bath will remove the yellow blotches which sometimes appear on pyro negatives because of developer in the fixing bath. Intensifying a Negative: First solution 120 grains mercuric chloride 120 grains potassium bromide 12 ounces water 49 40 THE MOTION PICTURE Second solution 1 ounce sulphite of soda 8 ounces water Soak the negative in the first solution until it is white, then wash thoroughly and soak in the second solution until it is as dark as desired. Wash thoroughly and dry. Reducing a Dense Negative: 32 ounces water 1 ounce hypo 15 grains of red prussiate potash Dissolve the hypo completely in half the water; dissolve the potash in the remaining water; and pour the potash into the hypo. Reducing Contrast in Negative: 8 ounces water 3 grains permanganate of potash 6 drops sulphuric acid Intensification. When the shadows of a negative are only gray, either because of too short exposure or too short development, or because of too long exposure and consequent very short development under the sight or factorial system of development, the printing quality of the negative may be improved by intensification by the mercury process, provided always that the negative is not spoiled by the amateur efforts at intensification. Intensification and reduc- tion of negatives should be avoided by mastering the art of exposure. Reduction. When the entire negative is too dense, use the potash reducer. When the clear portions print satisfactorily but the dark portions are too dense, giving too much contrast in the print, use the permanganate reducer. Except with skill, the negative may be ruined with either. It is well to experiment on a few negatives of small value before attempting either reduction or intensification of a precious picture and make a few prints from the negative before risking it by intensifying or reducing. Retouching and Spotting. Retouching consists of working upon the negative, usually with pencils, to improve its quality or to modify the image. First, varnish the negative with a good retouching var- nish. Then, working with a fine pencil point, a dark line in the print, as a wrinkle in a face, which shows as a light line in the negative, may be so penciled over that it is much reduced in the print or does 60 PHOTOGRAPHY 41 not show at all. Retouching is a task which usually requires special training and much skill. Pin-holes. Small transparent spots sometimes appear in a nega- tive, resembling pin-holes in appearance, due to defect in the gelatine of the plate, to grains of dust on the plate during exposure keeping the light from striking the plate under the dust grain, or to air bubbles clinging to the plate during development. These may be blacked in by a weak solution of India ink applied with a small camel's-hair brush formed down to an extremely fine point. Several applications of a thin color, just touching the spot with the tip of the brush until the film absorbs the ink, will gradually darken the pin-hole until it matches the part of the negative immediately surrounding it. An opaque spot on the negative, such as might be produced by a grain of dust caught by the film while drying, or by an overspotted pin- hole, will make a light spot on the print, which then may be spotted out upon each print with India ink in the same manner as upon the negative. PRINTING Printing consists of transferring the image from the glass nega- tive to a sheet of sensitive paper, and then rendering the paper in- sensitive so that the transferred image cannot change. This trans- fer of the image to the printing paper is effected without changing or injuring the negative, and as many finished prints as are desired may be made from one negative. The negative is not a reproduction of the view, but a record of the image in reversed or "negative" form, with the lights of the view showing dark and the shadows showing light. The print is made from the negative by the use of chemicals which discolor when acted upon by light, giving a shadow in the print where the negative is clear, and a high light where the negative shows dark. The print thus is a "negative of a negative," and shows the, view in its proper relation of light and shade. Processes. Four processes of printing, or producing positive pictures from photographic negatives, are in general use: (1) Printing-out toning processes; (#) Printing-out self-toning processes; (#) Developing or gaslight processes; (4) Enlarging or lens-printing. 51 42 THE MOTION PICTURE In each case, the process consists of subjecting a sheet of sensitized printing paper to the action of light which has passed through the negative, then "fixing" the print thus made. Printing Frame. The printing frame consists of two parts, frame and back. The frame is open, with a rabbet of proper size to take the glass negative as a piece of glass is placed in a picture frame. The back is in two parts, hinged together, each part having spring clamps for fastening it into the frame. The negative and then the print paper are put in the frame, the back is put on, and the clamps closed. The loaded frame is placed in the sunlight and the printing paper is discolored by the light passing through the negative. By unclamping one part of the back and opening it on its hinge carefully, the progress of the print may be observed. The remain- ing clamped part of the back holds the print paper and the negative in alignment while the free end of the print is looked at. Printing=out Papers. These papers are so called because the pictures "print out" or become visible while the paper is printing in the sun. The printing paper consists of a sheet of paper with a film on one side, similar to the film of a glass plate, but very much less rapid, or less sensitive to light. In handling it, the red light is not required, as ordinary gas light or the light of an oil lamp does not affect the paper. Subdued daylight, as in a room with the shades drawn, usually is safe and does not affect the printing-out paper. Chloride Papers. The usual "silver" paper consists of chloride of silver held in a surface of gelatine, collodion, or albumen. It requires the three steps of printing in the frame, toning in a gold bath, and then fixing in hypo, in addition to many wash waters, to produce the finished print ready for mounting upon a card. To print, lay the printing frame face down, lay the negative in the printing frame with the film side up, lay the piece of printing paper on the negative with the sensitive side down, then a pad of half a dozen pieces of newspaper cut the right size, then put in the back and fasten the clamps. When thus filled, place the frame in the strongest light possible direct sunlight is best with the glass side toward the sun. The progress of printing may be watched by looking at one half of the print from time to time, opening the frame and turning back the end of the print, as shown in Fig. 28. This examination must be made in the shade, at least with the frame PHOTOGRAPHY 43 held in the shadow of the operator's body. Continue the printing until the picture is much darker than desired in the finished photo- graph. Print until the details in the half-tones have disappeared, indeed until the print seems spoiled. It will fade back in the toning, fixing, and washing to give what is wanted. The degree of over-print- ing can be learned only by experi- ence and practice. There are many different brands of paper offered by manufacturers, and the explicit instructions which accompany each package of print- ing paper should be followed. At Fig ' 28 ' J!S&*5ft8** ' r first, use a toning bath bought ready mixed, if it can be bought especially prepared for the particular paper used. The formulas which follow are representative, and are adapted for most chloride printing-out papers. Washing before Toning. Place the prints in running water or wash through several changes until the wash water no longer shows milkiness. The silver unaffected by light will be washed out. The prints will get lighter and reddish in color. Keep the prints moving while in the wash water. Toning. Make two stock solutions. Gold Solution 7^ grains pure chloride of gold 8 ounces pure water or 15 grains chloride of gold and sodium may be used instead of the pure chloride. Soda Solution Pure water Bicarbonate of soda to saturate By saturation is meant to put into the bottle of water all the soda crystals it will dissolve. For a dozen 4 by 5 prints, shake the bottle of gold and take one- half ounce of the solution and eight ounces of water, place a piece of red litmus paper in it and add the soda solution drop by drop until the litmus paper begins to turn blue. If the litmus paper turns 53 44 THE MOTION PICTURE blue too rapidly, add a drop or two more of the gold to slow it. A fresh piece of litmus paper should show slight blue at the end of one minute. This toning bath must be nicely balanced between the gold and soda, and then left for half an hour to ripen before using. Mix the toning bath, and let it ripen while washing the prints. Place the washed prints in the toning bath and keep them moving. Stopping. The prints will change in color through a range of browns to purple or black. They may be stopped brown or at any shade desired. When any print has reached its desired shade, change it to the stop solution. Stop Solution 1 ounce table salt 1 gallon water Fixing. When all prints are toned and stopped, place them in a fixing bath and keep them moving for twenty minutes. The alum fixing bath is preferable. Soda Fixing Bath 1 gallon water 1 pound hyposulphite of soda Alum Fixing Bath 1 gallon water 8 ounces hyposulphite of soda, crystals 3 ounces alum, crystals I ounce sulphite of soda, crystals 1 ounce borax Dissolve the borax in a pint of hot water. Dissolve the remain- ing chemicals in the remaining water, then pour in the borax solu- tion. This bath must be made up the day before it is needed. It keeps indefinitely both before and after using but should not be used after fixing two dozen 4 by 5 prints to the pint. Final Washing. After fixing, the hypo must be thoroughly washed out or the prints will become discolored with age. Wash for an hour in running water, or for two hours in changing water, changing the water at first every five minutes. To change the water on the prints, use two dishes, lifting the prints one by one from the first dish into the second, with a moment of draining. 54 PHOTOGRAPHY 45 Combined Toning and Fixing. Two stock solutions are re- quired, soda and gold. Stock Soda Solution 8 ounces hyposulphite of soda, crystals G ounces alum, crystals 2 ounces granulated sugar 2 ounces borax 88 ounces water Dissolve the borax in a half-pint of hot water; dissolve the remaining chemicals in the remaining water, cold, and pour in the borax. Let stand over night and pour off the clear liquid. Stock Gold Solution 7J grains pure chloride of gold 64 grains acetate of lead 8 ounces water Fifteen grains chloride of gold and sodium may be used instead of the pure chloride of gold. Do not filter. Shake before using. For fifteen 4 by 5 prints, take 8 ounces of stock soda and one ounce of stock gold and put in the dry, raw prints without washing before toning. When properly toned, stop them in a solution of 1 ounce of salt and 1 quart of water. Then if possible use the acid fixing bath for ten minutes to ensure thorough fixing. Wash finally for an hour in running water, or the equivalent in changing waters. The formula given for the combined toning and fixing bath is a thoroughly tested one, and may be bought ready mixed under the name of "Solio Toning Solution." Self=Toning Paper. These are printing-out papers which take a brown tone without the use of the gold toning solution. Their manipulation is much simpler than the ordinary printing-out papers. Some of them require only washing in water to tone and to render the print permanent. Others require a hypo solution, but in all instances the claim of self-toning is justified by the simplicity of the operations required after printing. Blue Prints. When purchased, the blue print paper has one side coated with a sensitizing solution containing iron. The coated side varies from a light yellow to green in color. When printed under a negative in a printing frame in the sun as with any other printing- 55 46 THE MOTION PICTURE out paper, the image comes up a dull dark blue and the shadows change to a gray or bronze appearance. Print until the deep shadows are bronze and until the detail is lost and the print seems spoiled. Then wash in clear water until all the yellow is washed out of the print and dry. Too long washing will lose the details and half tones of the picture. The picture is blue and white, and is permanent. Sepia. Print as for blue prints, but develop in a very weak solution of hyposulphite of soda before final washing. If the hypo is too strong, the prints will fade in the bath. The sepia print must be placed in the hypo and then in the wash water instantly when re- moved from the printing frame; it will not "keep" even a few minutes. Developing Papers. The amateur who is employed during the day will find his time best disposed and will get the most enjoyment out of his photographic occupations by using his holidays in the field with his camera making exposures for new negatives and by making his prints by artificial light in the evenings. The printing papers which are offered for contact printing by artificial light are sub- stantially slow plate films spread upon paper supports. The proc- esses of exposure, development, and fixing are substantially the same. Pyro cannot be used. The hydro-metol formula for developer for plates and the fixing baths either plain or acid are proper for developing papers. The acid fixing bath is preferred. Visual de- velopment is entirely satisfactory and factorial or tank development need not be attempted. With normal working and a normal negative, a finished print is in the fixing bath in less than one minute after the neg- ative and paper are put in the printing frame, giving a decided advan- tage for the amateur over the slower processes of printing-out papers. The sensitive coating of developing papers is made much slower in response to light than the coating used for plates, so much so that red light is unnecessary. The developing trays may be placed upon a table 6 feet or more from a gas jet, but when developing the operator should stand with his back to the gas jet and with the shadow of his body falling over the developing tray. The paper should be kept covered or wrapped in black paper before printing, and should be loaded into the printing frame in the shadow of the operator's body. The printing outfit required consists of a printing frame, Fig. 28, and three developing trays. Place the three trays in a row, 56 PHOTOGRAPHY 47 developer in the left, water in the middle, and fixing bath in the right. The trays are very convenient if of a larger size than the prints to be made, and the quantity of solutions contained must be liberal. Each print passed through the developer consumes some of the strength of the solution, thus weakening it, and if the quan- tity of the developer is small the print may weaken it to such an extent that two prints from the same negative and having the same exposure will develop differently because of the weakening of a small quantity of developer by the first of the prints. A developer may be used repeatedly until it becomes too slow in action. Developing papers may be printed by exposing the loaded printing frame to daylight, but daylight is so variable from minute to minute, if there are clouds in the sky, that an element of uncer- tainty and, therefore, an element of failure is brought into the opera- tion of making the prints. Artificial light usually is constant and is preferable for that reason. With a 4 by 5 printing frame, loaded with a medium negative, and held 7 inches from an ordinary gas or incandescent electric lamp, a trial exposure of twenty seconds may be made. Remove the paper from the frame it shows no image and immerse in the developer. In fifteen seconds it should be com- pletely developed, and unless transferred quickly to the water it will be over-developed. Rinse for a few seconds in the water to remove the developer from the surface and place it in the fixing bath. After fifteen minutes in the fixing bath, wash and dry. To be able to stop the development at the proper instant upon an over-exposed print, lift the print when development is nearly complete and let the develop- ing solution drain back into the tray. The print will continue develop- ing for a few seconds while held in the air, because of the developer which clings to the surface. At the proper instant, plunge it into the wash water, which will stop development almost instantly, and then into the fixing bath. Turn an under-exposed print face down in the developing tray to avoid fog during prolonged development. If with a proper exposure the whites of the picture are gray before the shadows are deep enough, the addition of a few drops of a solution of bromide of potassium 1 ounce bromide of potassium dissolved in 10 ounces water will tend to keep them clear. Too much bromide in the developer will give olive tones to the print. Old and slow developerwill give purplish tones to the print. Fresh normal devel- 57 48 THE MOTION PICTURE oper, without too much bromide will give pure blacks and whites with untinted half tones throughout the entire range from light to shadow. The time of development should be about fifteen seconds with normal developer, average negatives, and regular qualities of develop- ing papers. The amount of exposure should be gauged to require this time of development. The length of exposure may be regulated to some extent by the distance between the light and the printing frame. Double the distance for the same negative requires four times the length of exposure, and half the distance requires but one- quarter the length of exposure, but if the printing frame is brought too near the light the center of the picture will be printed darker than the edges and the heat may crack the glass negative. If the length of exposure is shorter than twenty seconds, increase the distance from the light and give a longer exposure. It is very difficult to time accurately an exposure of less than twenty seconds, and by adopting a longer exposure the proper length may be given more accurately. The adjustment of exposure by distance also involves printing a thin negative by weak light and a dense negative by strong light, a rule usually recommended by the makers of gaslight papers. To secure uniformity of illumination over the entire negative, a 4 by 5 frame should not be exposed closer than 7 inches from the light, and a 5 by 7 frame not closer than 10 inches. Several different brands of developing papers are to be bought in the market, all differing from each other to some extent, and for each brand the manufacturer advises a specific treatment, de- veloper compound, etc. The instructions with the paper should be read carefully until understood. Lens Printing. In a contact print, the images of the print always are of the exact size of the images in the negative; it is not possible in a contact print to make a print larger than the negative, and it is possible to make a print smaller than the negative only by omitting some portion of the view, such as the margins, the images actually printed being of the size of those of the negative. By printing through a lens it is possible to change the size of the images of the picture, producing a print either smaller or larger than the negative from which it is taken. Printing through a lens is a process requiring longer exposures or more sensitive printing paper than contact printing, since ail 58 FOOD FOR THE HUNGRY Scene from Photoplay, "How He Redeemed Hi Courtesy of the Champion Film Company, Neu self ' York SCENE FROM PHOTOPLAY, "THREE OF A KIND" Courtesy of Independent Moving Pictures Co., New York PHOTOGRAPHY 49 the light which may fall upon the negative cannot be passed through the negative and lens effectively to act upon the print paper. To bring the time of exposure within reasonable limits, a paper called bromide paper is used. This is much more sensitive to light than the brands used for contact printing. When arrangements are made to illuminate the negative by daylight, the use of bromide paper will bring the exposures frequently to less than one minute in length. The length of exposure will depend upon the size of the enlarged picture, as well as upon the size and density of the negative, the diaphragm stop of the lens used, and the intensity of the light. Bromide paper cannot be handled in daylight or in gaslight, as ordinary developing papers. are handled, but must be worked in the darkroom. It is developed and fixed as the ordinary develop- ing papers are, the developing and fixing formulas given for the developing papers being in general suitable for bromide papers, but in the case of the bromide papers the instructions accompany- ing each brand of paper should also be studied until understood, and if possible the exact formulas which accompany the paper should be used in working the paper. The manufacturer has done all the experimenting necessary to produce good results. Enlargements. To make an enlargement, a window must be closed with a tight screen having a hole in it a little larger than the negative, and at such a height that the camera may be backed up against the hole to close it. A cloth thrown about the camera when thus placed will seal the window light tight. Cut the middle partition out of a double plate-holder so that when a negative is placed in the plate-holder it will be held by the edges only. Remove the ground glass from the camera, place a negative in the plate- holder and place the plate-holder in the camera. Place a white screen vertically in front of the camera, and focus the negative upon it by racking the front of the camera out to the proper focus. To make the image upon the screen larger, move the screen farther from the camera; to make the image smaller, move the screen nearer to the camera. If the window does not open directly to the free sky, a mirror may be placed outside the window to reflect the free sky into the negative. The arrangement with mirror is shown in Fig. 29. The only light entering the room is that passing through the negative and the lens. 59 50 THE MOTION PICTURE To make a test exposure, place a piece of ruby glass in front of the lens and tack upon the screen a strip of bromide paper. Remove the ruby glass from the lens for one-half minute and cover one- quarter of the strip of bromide. Again remove the ruby glass from the lens for one-half minute and then cover the second quarter of the bromide strip, which now has had one minute. Remove the ruby glass from the lens for one minute and cover the third quarter of the bromide strip, which now has had two minutes. Remove the ruby glass from the lens for two minutes, giving the remaining Fig. 29. Camera Arranged for Daylight Enlarging quarter of the bromide strip four minutes in all. Develop the strip, and it will tell which exposure is correct, or between which two values the correct time will be found. When this is known, tack a full-size piece of bromide paper on the screen and expose for the determined length of time, developing, fixing, and washing the resulting print. Lens caps fitted with ruby or orange glass may be bought for capping the lens while pinning the bromide paper to the screen for exposure. The advantage of such a colored glass cap is that it leaves the image visible upon the screen and the bromide paper may be correctly placed. This is of particular value when only a part of the whole negative is to be printed in the enlargement. 60 PHOTOGRAPHY 51 SPECIAL APPLICATIONS OF PHOTOGRAPHY Lantern Slides. To tell a long story in a short way, the lantern slide is a print on glass instead of on paper. Lantern-slide plates are sensitized usually with the same chemicals used in bromide paper. They may be printed by contact printing as any developing paper is printed, or may be printed by lens printing. In either case, they must be handled by darkroom methods, because they are as sensitive as the bromide paper and nearly as sensitive (about one-twentieth) as the dry plates used for negatives. The American lantern slide is always of a standard size, 3 by 4 inches. Foreign slides sometimes have other dimensions. Upon this size of plate, the actual picture for projection by the lantern seldom is larger than 2f by 2f inches. Where the image to be printed upon the lantern slide is contained within this space in the negative, the slide may be printed by contact, but where the image in the negative is larger than 3 by 3 inches, it will be necessary to employ the process of lens printing. As the lantern slide is but a bromide print on glass, all of the instructions for lens printing on paper apply directly to the making of a lens-printed lantern slide. The lens printing of the lantern slide will be necessarily "copying down" or reducing rather than enlarging, meaning that the screen upon which the picture is focused will be closer to the lens and will require a longer draw for the camera bellows. If necessary, a box with both ends open may be introduced against the window, holding the negative against the window, the back end of the camera being against the other end of the box, thus providing an extension to the length of the total draw obtainable by the box and the bellows to- gether. Correction for the thickness of the glass of the lantern- slide plate must be made to secure proper focus, but a ground glass may be focused upon and the slide plate substituted for exposure. Another method of lens printing for lantern slides when the reductions are considerable, is to place the lantern-slide plate in the plate-holder of the camera, place the negative in the window, and focus the ground glass of the camera upon it with the lens end of the bellows toward the negative, inserting the lantern-slide plate with the dark slide and exposing as in a field exposure, thus actually making a photograph of the negative. 01 52 THE MOTION PICTURE Place a lantern-slide mask upon the completed glass print, place a cover glass over it, and bind the edges with lantern-slide binding strip, and the slide is finished. Stereographs. These double pictures are adapted to present two slightly different images of the same object to the two eyes when viewing the stereograph, the two images being different in just the details wherein the two eyes of the observer would see the physical object differently by reason of the difference between the viewpoints of the observer's eyes. The two pictures of the stereo- graph are made simultaneously by a camera having two lenses side by side. A two-image negative thus is produced, a two-image print is made from it, and the two images are cut apart and pasted upon a card for viewing through the lenses of the stereoscope. By reason of the lens reversal of the images in the camera, the images of the print must be transposed before pasting upon the card. The dis- tance between the lenses usually is about 3^ inches; between the prints on the stereograph mount, about 2f inches. This gives a slightly exaggerated perspective, increasing the illusion of perspective and solidity when the stereograph is viewed properly. While the paired lenses are desirable, stereographs of still objects or scenes may be made by an amateur by two successive exposures of the same camera, the camera being moved 3 or 4 inches between the two exposures. Use a small lens stop, as great depth of focus is desirable in a stereo- graph. Panoramas. The ordinary photographic lens places upon the ground glass an image which includes about sixty degrees of the horizon. Wide-angle lenses are lenses of short focus for comparatively large plates and sometimes cover one hundred degrees or more. Negatives including more of the horizon than any single fixed lens can make have been obtained by a swinging lens. A camera of this nature has a sensitive film held in a semicircle, and has its lens mounted in a swinging frame which gives an exposure of but a nar- row vertical slit upon the film. As the lens swings, nearly one-half of the horizon is impressed upon the film in a continuous image. Another type of panoramic camera has gears for revolving it upon the tripod top and winds a roll of film behind the slit of a lens while the camera is revolving. With this camera an image may be made including the entire horizon. 62 PHOTOGRAPHY 53 Panoramic prints may be made by the amateur by making two or more plate exposures and pasting the prints upon a card with the edges carefully trimmed and matched. In making such exposures intended for panoramic mounting, the vertical line of matching should be in mind when arranging the image upon the ground glass. Only the double lens should be used, as the distor- tion of the single lens will be seen when the edges are matched in the finished picture. Telephotography. Quite the opposite of panoramic photog- raphy is telephotography, which is the art of enlarging a small por- tion of the view to fill the entire plate. The production of a large image of a distant object is the result which telephotography en- Fig. 30. Glasses of a Telephoto Lens deavors to obtain. This is done directly in the camera by adding a third lens cell to the double lens; a negative cell, having a lens thinner in the middle than at the edges, spreads the middle part of the image to cover all of the plate. The arrangement of glasses in such a lens is shown in Fig. 30. The third, or negative, lens is mounted at the back end of a long lens tube and an ordinary double lens is mounted at the front. By the use of the telephotographic lens, a bellows extension of 12 inches may be sufficient to make an image upon_the ground glass as large as would be made by a lens of 48 or (')() inches in focal length. The time of exposure, however, is proportionately longer, and the enlarged image upon the ground glass is proportionately dim. Telephotography is a process for the enlargement of the image in the camera before it is recorded. The result does not differ from an enlargement made from a small por- tion of a negative taken from the same viewpoint, unless in greater sharpness of detail. 63 54 THE MOTION PICTURE Orthochromatic Photography. White light is made up of a mixture of colors, and colored objects are objects which separate the white light which falls upon them and give to the eye but a part of its component colors. Of all the visible colors, the blue and violet are the most active in affecting the photographic plate. There are also invisible rays, called ultra-violet rays, accompanying white light which are very powerful to affect the sensitive plate. With the blue light more powerful in action upon the sensitive plate, it is clear that when an exposure is made upon a subject containing blue, yellow, and red, as a bouquet of flowers, the light from blue blossoms will make a darker image in the negative and, therefore, a lighter image in the print than light from the red or yellow blossoms. Thus, a scene having colors will not be reproduced in its proper light and shadow values by the ordinary processes of amateur photography. A rosebush in bloom with white roses will give proper results, but an adjacent bush in bloom with red roses will appear in the photo- graph to have no blossoms at all, since the bright red of the blossoms is no more effective upon the sensitive plate than the dull green of the rose leaves, and the roses may be distinguished upon the bush only by their shape, as green apples upon a midsummer tree. To remedy this feature of the ordinary photographic processes and to render photography suitable for colored objects, a plate sensitive to yellow and slightly sensitive to red is made, and there is made also a colored screen, or "ray filter" for the lens which has the faculty of holding out a large portion of the blue and ultra-violet rays and permitting all of the yellow and red rays to pass. When such a plate, called an orthochromatic plate, is exposed to a lens image of light which has passed through a proper ray filter, the blues, yellows, and reds will all have equal effect upon the plate, and the resultant picture will show the view, not in. colors at all, but in proper values of light and shade regardless of color in the view. The objection to the universal use of the orthochrome plate and the ray filter is that from three to eight times the exposure is required. Colored Photographs. Any print may be colored by brush and suitable transparent dyes. If it is the wish to reproduce the actual colors of the scene, it is necessary that the negative be made with an orthochromatic plate, or it will be impossible to reproduce the 64 PHOTOGRAPHY 55 reds, since they will be black in the print. Photography in natural colors by camera and development processes without recourse to hand coloring is a problem which has been solved in several ways, yet no solution is entirely satisfactory. The most nearly satisfactory processes involve first, the separation of the light of the image into two, three, or four different colors; second, the photographing of the separate colors by separate negatives, the negatives being uncolored; third, the making of prints, one for each negative and each print of a single color in itself but of a color different from the other prints of the set; and fourth, combining the separately colored prints or arranging them in a viewing device such that all of the prints may be viewed at once. The colors, thus being placed upon each other, blend in the eye to form all the hues of the original view. Tri=Color Photography. Pieces of orange-red, green, and violet glass are required, of such size as to cover the lens of the camera. Tri-color results will largely depend upon the accuracy and purity of the hue of these colored ray filters. Having selected and focused the scene, expose three orthochromatic plates, one after another, each of them with one of the colored glasses in front of the lens. With a set of color filters used by the author, the exposure required is four times normal with the violet filter, thirty times normal with the green filter, and five hundred times normal with the orange filter. The negatives when developed will all look alike. Make three lantern-slide plates and cover each with a cover glass of the color through which the negative of that slide was made. In all slides, white objects are clear glass; shadows are black. Brightly colored objects remembered in the view will have different half- tone values in the three plates. A violet object is lightest in the violet plate. A blue object is darkest in the orange plate. A green object is lightest in the green plate. A yellow object is darkest in the violet plate. A red object is lightest in the orange plate. i-The three slides are projected by three lanterns upon the same screen and at the same time, when the colors will unite to give all the hues of the original view. The process is simple in theory, but requires very careful and accurate working to produce acceptable results. Autochrome Plates. By the use of these plates an amateur may make pictures in natural colors as simply as making a negative and paper print. Each exposure in the camera produces not a 65 56 THE MOTION PICTURE negative but a glass positive print in colors, suitable for direct view or for lantern slide if of proper size. The exposure is made through a special orange screen, and the time of exposure is about one hun- dred times the normal exposure for the same view and lens stop with ordinary plate and no ray filter. Autochrome plates differ from ordinary plates by having inter- posed between the sensitive coating and the glass a thin layer of transparent microscopical starch grains, dyed orange-red, green, and violet, spread without over-lapping, and mixed in such propor- tion that the layer appears colorless. The sensitive coating is ex- tremely thin, and made of a very fine-grained emulsion. When such a plate is exposed in the camera, the glass side toward the lens, the light before reaching the sensitive coating passes through the colored starch grains, which act individually as minute color filters, each one absorbing all colors but its own. A microscopical selection takes place, and after development there will be found under each grain a corresponding black image of a density proportionate to the amount of color received and transmitted by this particular grain. Were the plates fixed at this stage, the picture when examined by light passing through the plate would show only the colors complement- ary to those of the original, since the true colors are masked by the black images they created beneath the grains. The next step is to dissolve the black silver by an acid permanganate solution; then the plate is exposed to white light and re-developed, blackening the white silver left by the permanganate solution. The image now is reversed. Each color grain transmits light precisely of the same hue and proportionate intensity as the light transmitted by the grain when the exposure was made in the camera, and the view is seen in its natural colors. >., w . ate; II Si MOTOGRAPHY Motography, or motion photography, is compared with fixed or still photography at every point. It is contrasted with fixed photog- raphy in three important phases: First, the product desired; second, the methods of production required, which involve the author of the film story and the producer, with their assistants; and third, the means adopted, which involves the photographer and his special- ized photographic equipment. PRODUCT DESIRED Fundamentally, motography is the art of depicting motion by means of photography. Usually the associated step of projec- tion is used for viewing the motion depicted in the motion-picture film, but with this the photographer of the motion picture is hardly concerned. His picture when completed may be viewed by pro- jection, or by direct vision in a proper stepping device, or by close and careful study of the successive pictures, either alone or with two consecutive pictures placed over each other to reveal the differ- ences due to motion in the subject. Motion pictures may be made for scientific study or for purposes of amusement. Chronophotography. In this word, "chrono" means "time," and the object of the art of chronophotography is to photograph the condition of a moving subject at successive times in its move- ment. Such a process would produce if possible a sharp photograph of the subject at regular intervals, so that a careful study of the scries of pictures might reveal just what changes had taken place in the short interval of time between the taking of two successive pictures. The extreme positions taken by the subject and the posi- tions of the subject at critical instants may be observed in such a scries of pictures, enabling a scientist to study his subject in a manner that is hardly possible by any means other than chronophotography. Chronophotographic machines have been devised to make pictures at a rate as fast as five hundred pictures of the same subject Copyright, Hill, by American School of Correspondence. 2 THE MOTION PICTURE in one second. With a flying bird beating its wings at the rate of two beats per second, such a photograph would present two hundred and fifty different positions of the wings of the bird in beating the air, and certain of the images would show the extreme upper, the extreme lower, and the extreme outward positions of the wings, as well as showing the difference in positions of the wings in beating downward upon the air and in returning to the upper position. These photographs should be sharp and distinct as far as possible, that even the details of the wing feathers may be studied. Such a series of photographs should be of value to a student of flying ma- chines, but it is not recorded that any such good has come of it. In the study of a walking man, chronophotographic studies have been made by the military department of France and, as a result of those studies and experiments conducted in connection with them, it has been found possible to increase the endurance of infantry on march by teaching the soldiers an improved march- ing gait. In chronophotography, it is desired to photograph the sub- ject as it is rather than as the eye sees it, for because of its motion the eye of the observer may be deceived as to the actual positions taken and as to their actual order of occurrence. It is the object of chronophotography to reveal for the study of the scientist that which the eye is unable to see. Kinephotography. This is an older name for motography. In this word, "kine" means "motion," and the object of motography is to make a record of the motion of the subject in such a manner that by the use of the record the motion may be reproduced to the eye viewing the picture. In motography, it is desired to photograph the subject as the eye sees it rather than to reveal it as it is, and if because of the motion of the subject the eye is in any way deceived when viewing the phys- ical subject, then the true artist motographer will produce such a picture as will also deceive the eye in the same way and to the same extent when viewing the motion picture. The making of motion pictures is thus divided into two classes: motion pictures for scientific study chronophotography; and mo- tion pictures for amusement motography for motography is so largely an industry of amusement that its other phases may be con- 70 MOTOGRAPHY 3 sidered as subordinate. Chronophotography will be considered later as a subordinate phase of motography. Subjects. Primarily the proper subject for a motion picture is motion, or a subject containing motion. This is not a limitation, however, for still subjects are very forcibly presented in motion pictures when the camera itself has movement so that each of the successive images upon the film is made from a different viewpoint. Subjects are classified in the trade as travels, industrials, cur- rent events, dramas, comedies, and trick pictures. Travels, in- dustrials, and current events, are pictures in which the motographer finds his subject ready for his camera. It is necessary only to choose a viewpoint for the camera, and to choose an opportune moment, particularly for proper lighting, or if an interior is involved it may be necessary to provide artificial lighting. Dramas, comedies, chases, and trick pictures on the other hand are classes in which the motographer must create his subject. These form the bulk of the film industry and occupy the picture screens of the motion- picture theaters almost exclusively. These classes overlap each other, while science studies are a class apart. In many instances, a film picture might be classified in either of two or even more classes, according to one's own judgment. Travels. Travels include pictures showing the natural scenery of the country as the chief interest of the picture. The title takes a form indicating a journey or a visit to a country or place. The film is made up of many scenes, as though the motographer were enjoying a holiday with his camera and were photographing every- thing of interest to him, particularly everything typical of the place or country in which his visit is made, or of the line of travel over which his journey carries him. Industrials. Industrials are in substance similar to travels, the distinction being rather that the one takes the work of man as a subject and the other takes the work of nature. An industrial picture shows the production of something involving the industry of man. Factory industries when made the subject of motion pic- tures may include the production in the mine, farm, or forest of the raw material; views of the machinery with which the raw material is worked through its various stages of manufacture; views of the material itself in its successive stages of manufacture; and views of 71 4 THE MOTION PICTURE the finished product. Mining, farming, lumbering, and shipping, when made the subject of industrial motion pictures, verge upon the classification of travels. A decision as to whether the picture should be classified as travel or industrial should be based upon the manner in which the motographer has handled his subject. Current Events. Current events are substantially news pic- tures. Whether an event of interest becomes a part of a travel pic- ture, an industrial picture, or a current-event picture comparable to a newspaper illustration, depends largely upon the manner in which it is handled. "A Visit to London" (travel) may properly include views of water sports on the Thame^; "The Ice Industry" (industrial) may open with a scene of skating on the ice and close with spectators consuming ice-cold beverages while they watch a tennis game; a professional ball game or a prize-fight seems "indus- trial" within itself; "The Funeral of King Edward VII.," a splendid and impressive film, is properly classified as a news picture (current events). Dramas. Dramas are pictures which have a story to tell. They are comprised of a series of connected incidents which tell the story step-by-step as a staged production in pantomime yet do not contain the element of levity or burlesque to such an extent as to render the film classifiable as a comedy. The main object of the drama is to tell a story in a pleasing manner and in such a way that the story forms the fundamental feature of the entertainment, and not the actors, nor the stage setting, nor the separate incidents. Comedies. Comedies are pictures which are designed to tell a story with the sole intent of creating laughter. When in the nature of drama, the plot and its execution by the actors is light or bur- lesque in nature. Pictured jokes, pictured puns, pictured accidents with ludicrous results, awkwardness and confusion on the part of the actors, all furnish subject matter for this class of film pictures. Chases. Chases are a division of the comedy class, in which the stoiy involves the pursuit of some of the actors by others. A long series of ludicrous incidents may be strung together in a film, depicting the efforts of the pursued to evade his pursuers and the tribulations of the pursuers, ending the film either with or without a capture. Trick Pictures. Trick pictures are based upon the ability of 72 MOTOGRAPHY 5 the motographer to deceive the audience with film pictures produced by special manipulation of the motion-picture camera. Trick pic- tures usually are comedies in that the trick-picture art usually is used to produce laughter. Under this class, however, come pictures of transformations forming parts of more serious dramas, and some trick pictures themselves are wonders of illusion so profound that they have a charm of their own and offer a class of entertainment neither drama, nor comedy, nor chase, and classifiable only as "trick" or "spectacular." METHODS OF PRODUCTION Early Methods. Drawn Pictures. Motion pictures are almost as old as pictures, but until the advent of photography the motion picture was nothing but a scientific curiosity or a toy. The oldest motion-picture device of which we find record is the zoetrope, Fig. 1, a whirling device having a number of slits in a cylinder, and opposite each slit a picture. As the cylinder whirls, the pictures are seen in rapid succes- sion, and the whirling may be so rapid that the pictures seem all piled upon each other. When the device is turned at proper speed, persistence of vision holds one picture until the next is seen. By drawing the pic- tures by hand, taking care to simulate successive positions of an object, the object will seem to have motion when the device is whirled and the pictures are seen successively. Since the advent of the first picture-viewing device and before the advent of photography, a large number of designs of viewing or even of projecting apparatus for motion pictures had been pro- duced, but no devices for making the pictures to be viewed. The making of the many pictures by hand was a well nigh impossible task. In such a series, the fixed objects must be exactly alike in all of the pictures of the series or there will seem to be motion in the fixed things of the picture. The moving objects must be similar Fig. The Zoetrope 73 6 THE MOTION PICTURE in all details and must vary in position only, and the variation in position must be in harmony throughout all the moving objects of the scene. A compromise was effected by one progressive experi- menter, who projected his fixed objects from a fixed lantern slide and projected upon that fixed scene his carefully drawn moving images. In this way he simulated the entrances, gestures, and exits of actors upon a stage setting, and in the light of more modern his- tory it is but reasonable to think that perhaps he supplied also spoken words for the actors, thereby anticipating in a measure the modern "talking pictures." Photographic Process. With the discovery of photography came the realization that here was a new agent for the production of pictures' for the moving-picture exhibiting apparatus. The diffi- culty to be met was in photographing moving scenes with photo- graphs taken in such quick succession that the movement between two successive images would be so small that the two images would seem to blend into one as the hand-drawn pictures of the zoetrope did when the new photographs were substituted for the old hand- drawn images. Separate Cameras. The first solution was by Muybridge who, in 1877, arranged a row of twenty-four cameras with string-trigger shutters, the string of each shutter being stretched across a race track. A horse rapidly driven down this race track broke the strings and released the shutters as the horse was opposite each camera, thus taking a series of pictures within a very short period of time. When these plates had been developed and compared and matched up, it was found that a set of them could be arranged to show the successive positions of the running horse. This set comprising only a limited number of images was suitable to be shown in any of the motion-picture viewing devices then known. Multiple Camera. The next solution was that of LePrince, about ten years later, who arranged a multiple camera. This, in substance, was a battery of sixteen automatically reloading cameras, using strip film. Each camera would make one picture and while the remaining fifteen cameras were making fifteen more pictures in regular sequence, the first camera would automatically bring a fresh film into position to make the seventeenth picture in its turn, and so repeatedly the sixteen cameras would operate to make a con- 74 Ml S is ,3 S"o gs>> O S " iP u MOTOGRAPHY 7 tinuous series of photographs. This LePrince camera was the immediate ancestor of the modern motion-picture camera, being built in a single case with battery of sixteen lenses and sixteen shut- ters, all operated by a single continuously turned crank. The pic- tures were taken upon four strips of film. By printing four positive strips and passing them through the same battery of lenses and shutters, projection could be accomplished, or the pictures could be cut apart and pasted into a single strip such as is used in a modern projecting machine. Modern Methods. The features of the modern motion picture which are improvements upon the earlier forms and which render it adaptable for its present amusement purposes are the production of the images by photography; the flexible negative film which per- mits a large number of pictures to be taken quickly in succession upon a single strip of negative record; the transparent support for the positive print or positive film, permitting the picture to be pro- jected in an enlarged scale upon a screen so that it may be viewed by large audiences; and the system of registering holes in the margin of the films by which registry or alignment of the numerous pictures of the series is attained in the projecting machine. Motion pictures were fully reduced to a commercial entertain- ment means when it was possible to take a motion camera and a reel of negative film, to select a subject and expose the film upon the subject, to print the negative upon a strip of positive film and pro- duce a positive print, and to project that print upon a picture screen to be viewed by an audience. They were well received by the pub- lic from the beginning, and the industry grew rapidly from the first. In the beginning it was sufficient to photograph anything with movement, and the wonder of the projected picture was sufficient to hold the attention of the audience. A railway train passing, a fire engine, a waterfall, or the view from the car window was sufficient. The subjects, which were confined to "travel" and science studies, and occasional comedies, were enthusiastically received by the public. Dramas were not known. With the advent of the exclusively motion-picture theater, the demand for drama and comedy grew. It became necessary for motion-picture manufacturers to acquire studios suitable for stag- ing drama and comedy, to employ writers to furnish themes for 75 8 THE MOTION PICTURE motion-picture plays, to employ actors and stage directors to present the themes properly before the motion camera, and to employ scene painters and property men in a manner very similar to the opera- tion of a standard theater except that the seating capacity is absent and the play is produced but once in the studio. Division of Labor. When an industry has reached such a mag- nitude that many people are employed in its work Pathe" Freres have more than five thousand employes in France some employes will develop greater ability in some lines than in others, and the lines of activity become so divergent that they are best cared for separately. As in any manufacturing industry, the manufacture of motion-picture films for exhibition in a modern factory has its division of labor, and a film picture is the joint product of the various departments and specialists who in turn take it and perfect it with their skill. Four widely different classes of ability are involved, represented by four men, the author, the producer, the salesman, and the photographer, with their assistants. The author's stint begins with the conception of the thought and continues until the thought is reduced to motographable form. The "producer" takes charge of the total task at that point and carries the work forward until the motographic scenes of the picture have been recorded upon the sensitive film by the photographer. The photographer's duty comprises the carrying of the camera to the producer's scenes wherever they may be, recording the scenes photo- graphically, developing the negatives, and printing as many finished pictures as the salesman may require. The salesman most likely will be called the advertising manager of the film manufacturing company, but his ultimate duty is to sell the film product which the author, producer, and photographer have worked together to make. THE AUTHOR For the production of travels strictly, as travels were produced in the early days, perhaps no author is required. The modern tendency toward drama has modified the custom. It is in dramas, comedies, chases, and trick pictures that the author becomes promi- nent, and as these form the bulk of the motion-picture industry the author is always first to be considered. Much special training is necessary to become a successful motion-picture author. 76 MOTOGRAPHY -9 His Problems. Limitations of the Art. The limitations of the producer must be understood fully by the author. Few fiction writers create a successful drama for the histrionic stage at the first attempt, and their failures are due largely to a lack of knowledge of the limi- tations, of the technique, of the dramatic stage. Much more limiting are the requirements of the motion-picture producer with his studio stage, and voiceless actors. Many ambitious writers have submitted stories to the film manu- facturers in the hope that they might be found suitable for produc- tion in motion pictures, but very few of such stories are accept- able. The film manufacturer is still obliged to create his own plots, to write his own stories and scenarios, and to employ persons who have become trained to authorship under the limitations exercised by the producer and the tools he has to work with. Any limitation upon the maker of the film must of necessity be also a limitation upon the writer of the story which is to be told by the film. One limitation is the matter of color, for, unless the story is to be written especially for color production, no essential part or feature of the story or action may depend upon color. Another limitation is time of action, with an upper limit of twenty minutes or one reel of 1,000 feet of film for drama, and usually ten minutes or a half reel of film for comedies or trick pictures. Other limitations are the size of the stage which may be used, the costumes, stage settings, and stage properties, and last and most important of all the necessity of con- veying thought by action, gesture, and facial expression rather than by voice. Plot. The author must deliver an acceptable plot. The proper plot for a motion picture is one suitable for a short story of one thousand words in the current magazines rather than one suitable for a popular novel. The complete action must occur in twenty minutes, and this compels the story to be told as a short story, no matter how much there is to tell. The masterpieces of motion- picture drama consist of simple stories, simply told. The rule carries into comedy, trick, travel, and industrial pictures. A central thought forms the foundation of the story; this is embodied in a series of in- cidents involving as few leading characters as possible, for it is con- fusing to the audience to be obliged to carry too many characters in mind. An unnecessary character only confuses the spectator 77 10 THE MOTION PICTURE and leads the attention away from the principal characters and from the central thought which they are to give. The series of incidents should require as few stage settings as possible, for the same reason that multiplicity leads to confusion and confusion is undesirable. The time is short, twenty minutes, and the real story of the play must be told fully and plainly, not smothered with unnecessary scenes or incidents nor obscured with side thoughts. Lubin's "Woman Hater" offers a twenty-minute picture of a thousand feet of film staged with a single stage setting and only four characters, and it is one of the masterpieces. Essanay's "Justified" does the same with only three characters and a couple of supes. The plot is brief. It is only the central idea, the skeleton, the foundation. The title is not the least in importance, for it is the part which is advertised outside the theater and the detail upon which dependence is placed to draw the patrons from the sidewalk past the ticket window into the house. When a striking title is created in the author's mind, the plot is half written. Scenario. The scenario elaborates the plot into "dramatized" form, for the motion-picture play should be written as if for the stage, not in "fiction" form as for a magazine article. In the scenario, the characters are listed, the required scenic settings are listed, and the action scene by scene is recited. "Titles" are given in the order in which they are met from scene to scene. Under the name of "titles" are included notes written, .newspaper pages, or any matter which the audience inust read in the progress of the picture. SPECIMEN DRAMA SCRIP The following typical drama with but four leading characters was produced by the American Biograph Company. The scene settings are simple, only three scenes being set for studio, and those not requiring anything unusual in the way of scenery. The out- side scenes are such as may be found in any village. That one scene setting is used sevesal times and the total number of scenes thus increased is not objectionable. The plot will withstand success- fully a rigid analysis. The drama is divisible into four chapters, as the four acts in a staged play, each chapter having a definite part in the progress of the telling of the story. No scenes of crime or violence are involved, and no scenes of a nature to depress the spirits. 78 MOTOGRAPHY 11 TITLE A Midnight Cupid PLOT A tramp wanders into a club man's rooms and falls asleep. Club man, bored with society, finds tramp and finds in tramp's pocket letter asking tramp to return home. Club man for diversion assumes tramp's identity and goes to his home. Falls in love with tramp's childhood playmate. Tramp returns home. Club man, ousted in disgrace, elopes with girl. Pursued by girl's father. Overtaken in club man's rooms after marriage. Girl's father sees wealth and social position of club man and forgives. SCENARIO Cast of Characters Club man (C M) Tramp (T) Girl (G) Girl's Father (G F) as farmer Policeman Two servants to club man Guests at reception First farmer Second farmer Grocer Minister Lady, well dressed, age 40 Two or three men, well dressed Children Scene Sets Club man's rooms (Studio) Parlor (Studio) Interior cottage bedroom (Studio) City park (two sets) Outside village store Outside village cottage Village street Field Synopsis CHAPTER I. Prologue, giving the conditions under which the true action of the drama is to occur. SCENE 1. City park, first set. Discovered, T reading letter. Title: "Dear Joe: As the father of the girl who was your childhood's sweetheart, I ask you to come back home. (Sig.) Wm. Broadhurst." (Back to Scene 1.) T reads letter sorrowfully, searches pockets, no money; puts letter in upper outside coat pocket with edge visible; lies on bench, sleeps. 79 12 THE MOTION PICTURE Enter policeman, raps T on foot with club, "Move on." Exit policeman left. Exit T right. SCENE 2. CM room, well furnished, table, chairs, sofa; door back, door right. Discovered, CM opening mail. Bored look. Enter servant, brings full decanter, places on table; CM looks at decanter in disgust. CM signs to servant; exit servant back, returns with coat and hat; CM dons and exits back. Exit servant back. Title: "Seeking Food." SCENE 3. Same as Scene 2. Enter slowly T right. Calls (face business). Raps on table, indicates hunger, sees decanter, makes great show of resistance to temptation, drinks and falls asleep on sofa. SCENE 4. Parlor. Discovered, many guests. Enter CM. Several ladies overly attentive to CM, bores CM much. Exit CM. SCENE 5. Same as Scene 3. Discovered, T asleep. Enter back CM bored. Presently discovers T, calls. Enter two servants. Servants surprised. CM sees letter in T pocket, takes letter and reads. Title: (Repeat title showing letter in Scene 1 .) (Back to Scene 5.) CM (face and stage business) forms plan for a lark. CM puts money in T pocket in place of letter. Orders servants. Exeunt servants right, carrying T. Exit CM back. SCENE 6. City park, second set. Enter servants left carrying T; place T on bench. Exeunt servants left. Title: "The Club Man Plans to Take the Tramp's Place." SCENE 7. Same as Scene 5. Enter CM back dressed as tramp. Enter servants right. CM explains, servants try to dissuade but fruitlessly. Exit CM back; servants in despair. CHAPTER II. The normal or main action of the drama. SCENE 8. Outside Village Store. Discovered, grocer and first and sec- ond farmers. Enter CM as tramp. Shows letter to grocer. Grocer surprised, tells farmers, farmers surprised, all welcome CM. Grocer indicates direction, CM exit right. SCENE 9. Outside Village Cottage, back yard. Discovered, GF in chair. Enter from cottage G with newspaper, show of affection, G gives paper and exit into cottage. Enter CM right, inquires of GF, introduces self, GF refuses to accept identity, CM shows letter, GF accepts identity and welcomes CM, GF calls, enter G from cottage, introduction, surprise, welcome, face business of admiration by CM, all exeunt into cottage. Title: "Unpleasant Duty." SCENE 10. Same as Scene 9 '. Enter from cottage GF with hoe, and CM . Exeunt right. SCENE 11. Field. Enter GF and CM left. GF hands hoe, to CM and indicates work in field. CM takes off coat and begins awkwardly, GF scolds, CM works harder, exit GF left. Title: "Pleasant Duty." SCENE 12. Same as Scene 11. Discovered, CM hoeing in field. Busi- ness of weariness, lights cigarette, sits on coat. Enter G left. CM hides cigarette quickly, welcomes G. G indicates leaving together, exeunt together left. SCENE 13. Village Street. CM and G pass across together, right to left. MOTOGRAPHY 13 SCENE 14. Same as Scene 8 with children playing in extreme background. Discovered, grocer and first and second farmers. Enter CM and G right. Exeunt into store CM and grocer and first farmer. Second farmer proposes marriage to G, indicating his wealth. Refused by G. Exit G into store. En- ter from store G, grocer, first farmer and CM carrying packages. Exeunt CM and G right. Enter CM right, pays grocer, exit CM right. Stage business in- dicating that CM is accepted and well liked. SCENE 15. Same as Scene 9. Discovered, GF in chair. Enter CM and G right, welcome by GF, exit G into cottage, exit CM right, stage business by GF indicating that CM is accepted and well liked. CHAPTER III. The interfering action of the drama. SCENE 16. Same as Scene 6 . Discovered, T asleep. T wakes, remembers letter, finds paper money in pocket instead, is surprised, exit right in glee. SCENE 17. Same as Scene 14. Discovered, grocer, first and second farmers. Enter T right. Recognizes grocer, grocer denies T identity, exit grocer into store. T recognizes first farmer, first farmer denies T identity, guards his watch and exit right. T recognizes second farmer, but second farmer avoids hand and eludes T, making exit into store. T alone on stage, face business of wonder and surprise. Exit T right. SCENE 18. Same as Scene 15. Discovered, GF in chair. Enter T right, recognizes GF, GF denies T identity. T lip language and gesture, "I am me." - Title: "The Tramp Proves His Identity." (Back to Scene 18.) T (stage business) tells of accident while swimming and diving as a boy and shows scar on head, shows birthmark on neck. GF satisfied with identification, calls to cottage, G enters from cottage, introduc- tion, G surprised. GF angry, calls off stage right, CM enters right, shows agitation on seeing T, GF rages, GF orders CM away, G tries to follow, GF interferes, exit CM right, exeunt G, GF, and T into cottage. SCENE 19. Interior cottage bedroom, practical door at back opening in- ward with lock and key, practical window right. Enter G and GF, GF rages, G cries, GF puts key in door on outside, exit raging and closes door. G tries door to show it locked, sinks crying by bedside. CHAPTER IV. The resolution of the plot and the conclusion of the drama. SCENE 20. Same as Scene 13. Enter CM right, walking rapidly, hesi- tates, shows much money, laughs, turns, exit right. SCENE 21. Same as Scene 19. Discovered, G crying by bedside. Enter CM, head only at window, calls, G responds slowly, confusedly, then quickly. CM invites elopement, G consents, gets wrap, exit through window. SCEKE 22. Same as Scene 20. Discovered, first and second farmers approaching in extreme background. Enter CM and G right, talk, CM shows and offers money and by accident drops paper from pocket when taking money from pocket, G refuses money, embraces CM, exeunt G and CM left. Farmers reach foreground, converse excitedly. First farmer exit right. Second farmer sees paper, reads, and exit right. SCENE 23. Same as Scene 18. Discovered, GF in chair. Enter first farmer right, tells GF of elopement. GF exit to cottage. SCENE 24. Same as Scene 21. Enter GF by door, looks around room, notices open window, stage business of despair and rage, exit through door. 81 14 THE MOTION PICTURE SCENE 25. Same as Scene 23. Discovered, first farmer. Enter GF from * cottage, raging. Enter second farmer with paper, shows paper to GF. GF reads. All exit right, GF raging. Title: "The Marriage." SCENE 26. Same as Scene 5. Enter CM as tramp and G back. CM rings; enter two servant* back; CM orders first servant; exit first servant; CM orders second servant; exit second servant. Stage business of love scene. Enter first servant and woman, stylish, age 40, apparently relative of CM, introduction to G, enter two men well dressed. Enter second servant and minister. CM explains to minister; produces paper, apparently license to wed, and hands to minister; minister reads, indicates readiness, performs marriage ceremony; congratulations by all. In midst of confusion, enter GF raging and first and second farmers. GF tries to seize G; G clings to CM; servants and guests interfere; CM tells GF they are married; G tells GF they are married; minister tells GF they are married; GF in despair and rage, farmers in despair. Title: "Convinced of Son-In-Law's Wealth, Father Forgives." (Back to Scene 26 with minister talking to GF.) Minister explains to GF that CM owns the house. GF surprised, asks servants, who answer yes; asks men, asks woman, asks CM; all answer yes. Still hesitates, gesture of appeal from G, GF takes G and CM in arms and dances. All joyous. (End of picture.) SPECIMEN COMEDY The requirement of a comedy is that there be a laugh at the close, and as many before that as possible. In a comedy which is neither chase nor trick, the plot should show the successive steps of story telling: first, the prologue setting forth the conditions under which the action of the story is to occur; second, the action of the story, which may be in several parts; and last the resolution and conclusion. TITLE The Old Maid's Dream PLOT Comical spinster falls asleep on park bench; nearby sits man accompan- ied by large dog. Spinster dreams she is being kissed. Wakes and finds dog licking her face. SCENARIO Cast of Characters Spinster, burlesque in manner and attire Man, portly and dignified Dog, large and shaggy preferred Parlor Maid Several well dressed young men MOTOGRAPHY 15 Scene Sets Park with two adjacent seats Parlor Synopsis CHAPTER I. Prologue. SCENE 1. Park with two adjacent seats. Enter spinster right, takes nearest seat. Enter man and dog left, man takes remaining seat, spinster much disgusted. Man falls asleep. Spinster glowers and fusses but sticks to the seat and finally shows drowsiness. Title: "The Dream." SCENE 2. Parlor. Discovered, spinster reading letter and smiling much. Enter parlor maid, announces caller, exit and return with first young man. Exit parlor maid. Welcome of man by spinster, man begins to kiss spinster. Enter second young man unannounced, surprise and confusion of all; exit first young man hastily in confusion. Business of love-making by- second young man and spinster, young man begins to kiss spinster. Enter two more young men unannounced, surprise and confusion. Enter more young men, all give excess attention to spinster, then begin talking among themselves as if quarreling about spinster; meanwhile one young man is aside with spinster and begins kissing excessively. Title: "The Reality." SCENE 3. Same as Scene 1. Discovered, man on seat asleep and spin- ster on other seat asleep, dog licking spinster's face. Spinster wakes, horrified, l)elabors dog with umbrella and then belabors man with umbrella. Exit dog and man, left. Title: "But It Was a Lovely Dream." (Back to Scene 3.) Stage business of rage by spinster looking off left, then slowly subsides, sits on seat, clasps hands, smiles and looks upward in attitude of blissful reverie. (End of Picture.) The reviewing editor of a motion-picture manufacturing com- pany probably would read as far as "Dog," and reject the manu- script. Trained animals are almost an impossibility in motion- picture production. It would be necessary to find ah actress who possessed such a dog, or an actor who could make up as a spinster and who possessed a dog which would lick its master's face. Aside from this, there is the method of enticing the dog by food or sugar, but this is remote in probability of a successful picture. SPECIMEN CHASE AND TRICK SCRIP When trick pictures are written, the author must keep his trick > within the possibilities of the art. In chases, the author's scenes must be influenced by the opportunities of the producer. In the following "scrip" as the written story of a picture before produc- 16 THE MOTION PICTURE tion is called the title, plot, and scenario are given, and these should be followed by a set of trick notes by the author explaining for the benefit of the producer how the various trick scenes shall be or may be produced. TITLE High Jumping Johnnie PLOT Johnnie is an acrobat out of a job. Hungry, he buys a sandwich but has no money to pay. The sandwich man chases him. He runs into an apple cart, upsets it, and the apple man chases. Upsets stand of newsdealer, who joins chase. Upsets baby carriage, nurse joins chase. Collides with policeman, who joins chase. The chase now being on, Johnnie easily vaults a wall, which the others require ladders to climb. In a barn-yard, hay-loft door of barn is 8 feet from ground. Johnnie vaults in easily; others try, but must enter by door; when all are in, Johnnie jumps out of loft door and flees down a coun- try road toward a bridge. Johnnie jumps from bridge into water; pursuers follow; Johnnie jumps back from water onto bridge; pursuers must climb 'out over the bank. In hot pursuit down country road, Johnnie jumps sheer to the sky and catches a passing airship, making final getaway. (See trick notes; practical airship not required.) SCENARIO Cast of Characters High-Jumping Johnnie, an acrobat, must jump well, swim well, and have experience on the horizontal bar Double for Johnnie, or dummy substitute Men, first and second Aviator, and assistants Pursuers, including policeman, nurse, men, etc. Scene Sets Circus tent entrance or exterior (Studio) Another circus tent with entrance and sign (Studio) Cloud canvas on rollers. (See trick notes J and L) Bedroom (Studio) Office building entrance, with sign City street scenes Country scenes Bridge and water scene Property List SCENE 1. Bed, table, chairs, washstand, mirror, comb, washbowl, water pitcher, towel, dumb-bells, Indian clubs, circus bill. SCENE 2. Sign, packing box. SCENE 4. Sign. 84 MOTOGRAPHY 17 SCENE 5. Park seat, sandwich wagon with sandwich material com- plete, white apron and cap and large fork for sandwich man. SCENE 6. Apple cart and apples. SCENE 7. Trestles and boards to be knocked off; newspapers and magazines. SCENE 8. Baby carriage; dummy baby; stripe uniform for nurse. SCENE 9. Uniforms for two policemen. SCENE 10. Trestle for jump from fence; two or three ladders, say six-foot, eight-foot and ten-foot, one each. SCENE 14. Dummy for Johnnie if double is not available; duplicate costume for double if double is available. SCENE 17. Airship. (See trick notes.) SCENE 18. Horizontal bar. Synopsis CHAPTER I. Prologue. SCENE 1. Bedroom, poorly furnished; dumb-bells and Indian clubs on floor; circus bill announcing "High-Jumping Johnnie" on wall. Discovered, Johnnie washing face. Takes short turn with clubs or dumb-bells, dresses for street, stage business toward circus bill on wall, looks at watch, exit through door. Title: "Loses His Job." SCENE 2. Exterior of circus tent entrance. Sign on tent, "Closed by Sheriff." Discovered, first man sitting on packing box near tent wall, head in hands. Enter Johnnie, sees sign, consternation at sign, taps man on shoul- der, asks about sign, man shakes head. Johnnie indicates pocket and stage business of asking whether anybody gets any pay; man shakes head. Man assumes disconsolate pose again. Exit Johnnie, doleful. SCENE 3. Another circus tent entrance. Enter Johnnie at one side, exit into tent; enter from tent Johnnie and second man; Johnnie is asking for employment, stage business of showing that he is an acrobat; man shakes head always indicating no work for Johnnie. Exit man into tent. Exit Johnnie one side after stage business of disappointment and hunger. SCENE 4. Office building entrance. Sign at door reads, "Theater Agency. Vaudeville Acts Wanted." Enter Johnnie one side, sees sign, business of joy, exit into office building entrance; business of passers-by; enter Johnnie from office building entrance, sorrowfully. No work. Exit one' side after stage business of hunger. CHAPTER II. The Chase, in the city. SCENE 5. Edge of park; park seat left; red-hot sandwich man and cart at curb at right; camera set to panoram from seat to sandwich cart. Enter Johnnie, left, disconsolate. Hunger, despondency. Looks off stage right, be- comes thoughtful, rises and walks toward right. (Panoram camera to follow actor.) Stops at sandwich cart, talks with man, orders sandwich; man makes sandwich and hands to Johnnie; Johnnie takes bite; man asks for pay; Johnnie explains; man angry; Johnnie continues explaining; man threatens; Johnnie runs with sandwich; man follows with apron, cap, and fork; exit around convenient street corner. SCENE 6. City street. Discovered, apple man and cart. Enter Johnnie 85 18 THE MOTION PICTURE running, collides with cart and falls, but holds on to sandwich; scatters apples in street. Johnnie recovers feet, picks up an apple, puts apple in one pocket and sandwich in another and runs off stage. Enter sandwich man; exit sand- wich man and apple man pursuing Johnnie. SCENE 7. City street corner. News stand and attendant. Enter Johnnie running, collides with news display, upsetting it but keeps on running. Enter pursuers, business with newsdealer, who joins chase. Exeunt, running. SCENE 8. Residence street scene. Enter nurse with baby in carriage. Enter Johnnie running, collides with carriage, overturns carriage but keeps on running. Enter pursuers. Exeunt pursuers running, including nurse, baby, and carriage. SCENE 9. Street corner in residence district. Enter left up one street two policemen. Enter right up other street Johnnie running. At corner, Johnnie collides with policemen. Exit Johnnie, running, left. Enter right pursuers running after Johnnie, talk with policemen, exeunt all running left. SCENE 10. City or suburban scene with wall 8 feet high. Enter Johnnie, makes running jump sheer to top of wall (Trick Note A) and down on opposite side. Enter pursuers. Run to wall, attempt to climb but all fail. Exeunt two or three and enter again with short ladders, all scale wall and vanish on other side. CHAPTER III. The Chase, in the country. SCENE 11. Country with fence and gate. Discovered, Johnnie in back- ground, running toward camera, clears fence by leaping from earth to top of fence and again to earth (Trick Note B), runs toward camera, and exit. Enter pursuers who at first try to climb fence but discover gate and open it, passing through gate and toward camera and exeunt in pursuit. SCENE 12. A steep earth bank 5 feet high. (Note C.) Enter Johnnie on top of bank, leaps to bottom; enter pursuers, following and coming down bank; exit Johnnie on lower level; exeunt pursuers following. SCENE 13. Similar to Scene 11, adjacent part of same bank. Enter Johnnie on lower level, leaps to higher level (Trick Note D) and keeps on running. Exit Johnnie. Enter pursuers, lose much time in climbing to higher level. Exeunt. SCENE 14. A barnyard and barn, with doors at ground level and loft door about 8 feet above ground level. Enter Johnnie and leaps into open loft door (Trick Note E). Enter pursuers and try to make loft door but fail. Johnnie takes sandwich from pocket and takes a bite, sandwich man rages. All pursuers take lower door to barn. When all are in, Johnnie jumps from loft door and exit; pursuers appear in loft door, some falling through loft door to earth and others returning by lower door. Exeunt. (Note F.) SCENE 15. A country road with bridge in middle distance. Enter from foreground Johnnie and pursuers very close behind, all running toward bridge. SCENE 16. Near the bridge of Scene 14. Bridge is at left; the foreground is water under and near the bridge; in the middle ground is the distant bank of the river. Enter Johnnie, left, on bridge, closely pursued. Johnnie jumps from bridge into water, pursuers all follow. When all are in the water, Johnnie jumps sheer from the water to the bridge again (Trick Note G) and runs off bridge left; pursuers lose much time climbing out of water upon bank in middle ground and exeunt after Johnnie. 86 MOTOGRAPHY 19 CHAPTER IV. Conclusion. Title: "The Airship." SCENE 17. Open country, with airship or aeroplane on ground. Enter aviator and assistants, right; walk to airship; examine all parts carefully; aviator takes driver's seat, assistants start propellers and exeunt; airship starts and passes off stage, right, rising. (Trick Note H.) SCENE 18. Country road. Enter Johnnie and pursuers, from back- ground, running toward camera. All notice airship (off stage) and stop run- ning, looking up. Johnnie makes sheer leap to sky, from extreme foreground, off stage through top of picture. (Trick Note I.) Pursuers run forward and off stage, ' always looking upward, showing amazement and chagrin after Johnnie's leap. Title: "Safety at Last." SCENE 19. Airship in flight in foreground, clquds in background. (Note J.) Johnnie enters through bottom of picture, extreme foreground, :eizes airship and climbs aboard. (Trick Note K.) SCENE 20. (Note L.) Near view of airship. Discovered, Johnnie, who nearly fills the screen. Takes sandwich from pocket and apple from another and eats, with stage business downward as if to pursuers on earth below. (Note M.) SCENE 21. Country roadside. Discovered, all pursuers in state of collapse, one or two showing rage and gesticulating toward sky toward Johnnie in airship. (End of picture.) The average picture-play editor would read that "scrip" only so far as the first time he saw the word "airship," were it not that the mention of airship is coupled with the memorandum, "See Trick Note." TRICK NOTES Trick Note A. The leap to top of wall and the entrance may be made in one action with reversing camera. Johnnie takes position on top of wall, back to camera; mark chalk line around both feet; start reversing camera; Johnnie stoops, puts hands on top of wall, leaps backward to earth, easing leap with hands on wall; then runs backward off stage at entrance point. When re- versed in the print, this enters Johnnie and carries him to the top of the wall in a flying leap. To complete the scene, Johnnie takes same position on top of wall, feet in chalk lines, and assumes as nearly as possible same attitude; start direct camera; signal pursuers on; pursuers enter and Johnnie leaps forward from camera out of sight. A platform beyond the wall may shorten the leap, which should not have the aid of hands. The two actions, reverse and then direct, com- plete the scene. The leap to top of wall and the entrance may be made in two actions. First action: Johnnie takes position on top of wall, back to camera; mark chalk line both feet; start reversing camera; Johnnie stoops, puts hands on top of wall and leaps backward to earth, easing leap with hands on wall; mark carefully around feet and around hands i] hands touch earth. Second action: Start direct camera without actors; Johnnie enters, runs to wall, and takes exact position with feet as marked in jump from wall, assuming as nearly as possible the same attitude 87 20 THE MOTION PICTURE as when landing from the wall. Third action: The scene from top of wall, with direct camera, as before. The three actions, direct, then reverse, then direct, com- plete the scene. The leap before the reversing camera should be backward, not face toward the camera, and the effect of the hands upon the wall is that at the end of the rise they help Johnnie to gain the top with his feet and acquire a momentary equilib- rium there. The scene in two actions is preferred if Johnnie is competent to run backward realistically. If the three-action method is adopted, the change from the first entrance to the reversing action may be made either at the point of ' leaving the ground for the leap, or a few steps prior to rising. Trick Note B. Some method as for Trick Note A. Mark with chalk the position of the feet upon the top of the fence. With Johnnie "jumped" into the picture, running almost directly toward the camera and on the distant side of the fence, the awkwardness of running backward will be obscured and less running backward will be required, so that the two-action method should be thoroughly feasible. In the second action, enter the pursuers before Johnnie leaves the fence jumping down. Note C. One side of a railway cut ought to serve for this scene set. A water-washed gulley or river bluff with beach at bottom is suitable. Trick Note D. Same method as for Trick Note A. The backward leap for safety's sake, should be squarely backward and not diagonally over the bank. Use hands as before. Mark position of feet as before. Two-action method pre- ferred, and Johnnie may be "jumped" into the picture if desired. Trick Note E. Same method as for Trick Note A. As it is desirable that the pursuers shall enter as quickly after Johnnie, the last action of the scene may start with Johnnie in crouching position in loft door with back to camera, the pursuers coming on while he rises and turns to face out of the door. Note F. Scene 14 may be staged in a city house if preferred, selecting a house with high first floor, the windows being about 8 feet from the ground. Johnnie jumps into an open window, pursuers rage under window, then enter house up steps and through front door, then Johnnie jumps from window and runs. Trick Note Q. Scene 16 may be made according to any one of three methods, which may be named the double method, the dummy method, and the repeater method. The first is preferred if an actor for Johnnie's double is avail- able. The "double" method is so named because it uses two actors who are "doubles," looking so much alike or made up so much alike that the audience does not dis- tinguish them one from the other. As the substitute for Johnnie appears for but a brief period and is in active motion all the time, the resemblance need not be exceedingly accurate. In producing Scene 16 direct and reversing cameras are used. First action: Johnnie's double enters left, on bridge, direct camera running, and jumps from bridge into water, followed even before diving by the leaders of the pursuers, who plunge after him. Second action: When all pur- suers are in the water, start reversing camera. Pursuers make much splashing but make no progress in swimming forward, but anyone skilled in swimming backward may do so. Pinter the real Johnnie walking or running backward, entering left on bridge and walking backward to the point of diving, diving back- ward if he has sufficient skill in diving, a straight backward jump, striking the water feet first being preferred. Third action: Start direct camera. Pursuers may MOTOGRAPHY 21 swim forward now and climb out upon bank opposite camera, thence running across bridge and exeunt left. The actions are used in the scene in the order in which they are taken. In the last action Johnnie must not be seen, even though the camera must be stopped to get him out of the picture. The "dummy" method requires a weighted dummy resembling Johnnie. In the first action, the real Johnnie runs on left and crouches upon the edge of the bridge, simulating a leap as nearly as possible, but does not go into the water. The camera is stopped, a dummy is substituted, held by a string running off stage; start the camera, release dummy by the string and order pursuers on. The dummy is weighted to sink when it strikes the water. Second and third actions as before. Poorest of the three methods. The "repeater" method requires Johnnie to dive twice and uses a dummy as well, but the dummy merely makes a splash and does not appear in the picture, so a weighted bag is sufficient. The first action is in two parts. Johnnie runs on left and dives from bridge; stop camera; Johnnie comes from water; dummy is fixed to bridge to be released to make splash by pull of string running off stage. Start direct camera, release dummy weight for splash, order pursuers on as water splashes. Second and third actions as before, the second action being all the better because Johnnie's clothes show wet. Trick Note H. Scene made in two actions, the second action being with reversing camera. Build a dummy aeroplane after the Wright biplane model, an easy type to copy in dummy. Arrange it to slide backward to earth on a pair or more of inclined wires. Must have practical propellers turning very easily by slight breeze. Make second action of scene before making first action. Second action: With reversing camera. Enter airship with aviator in driver's seat, sliding backward down inclined wires, propellers turning. Airship stops on ground, but propellers keep on turning; aviator takes tableau attitude to be assumed again in first action. First action: With direct camera. Discovered, the aeroplane just as it was in tableau of second action, but without aviator and with propellers stopped. Propellers may be tied to frame with a light string easily, broken. A sufficient breeze should be blowing to turn the propellers continuously after they have started. Enter aviator and assistants, or they may be "discovered" or "jumped in." In- spect airship thoroughly. Aviator takes scat; ass-istants start propellers by turning them forcibly which breaks string and breeze then keeps them turning. Exeunt all assistants left. Aviator in driver's seat assumes the tableau pose of the second action, made at the close of the second action in front of the reversing camera and, therefore, appearing at the beginning of the second action of the scene in reproduction . In lieu of the dummy airship and the staged action, a bona fide" airship or aeroplane making a bona fide start or a view of an airship in flight would serve the purposes of Scene 17. Stock actors need not appear in the scene. One direct action scene of a bona fide airship under any condition of motion would be all that the scene requires, the trick feature of the start of the dummy being entirely obviated. The entire scries of scenes involving the airship or aeroplane may be made with a free balloon instead, if the properties are more easily available to the pro- ducer. Scene 17 is then a bona fide scene of any balloon ascension. In Scene 18, Johnnie leaps to catch a dangling rope. Scene 19, the basket of the balloon is seen 89 22 THE MOTION PICTURE and Johnnie enters by climbing the rope through the bottom of the picture. Scene 20 is staged in the balloon basket. Trick Note I. In front of the camera and as high as Johnnie can jump and catch is a fixed horizontal bar such as acrobats use. The camera is set to take the ground below the bar as the foreground line of the picture and to clear a foot or more between the bar and the upper line of the picture, the bar being above the picture. With a bar 7 to 8 feet from the ground and with a 3-inch lens in the camera, the distance from camera to bar would be about 24 feet. The 'distance between standards supporting the bar must be more than 8 feet that the standards may be out of the picture. The shadow if any must fall toward the camera, that it may not show in the picture. When Johnnie leaps and catches the bar he pulls himself out of the picture as rapidly as possible, and at that time all eyes have been fixed above the horizontal bar, as though the airship were just there, and as though Johnnie hat jumped and caught the airship. If he can get out of the picture quickly enough, it will seem that he has jumped higher than the picture to catch the airship. Trick Note J. The airship (dummy or bona fide) is rigidly supported by invisible wires or by trestles at its ends, in the latter case the camera being set close and the trestles being off the sides of the picture. Flight is simulated by painting clouds on a canvas band and mounting the canvas on rollers and moving the clouds past the ship as a moving background. A slight panoram movement and vertical rocking movement of the camera simulates the tipping and swerving of the airship in flight. Trick Note K. Johnnie enters by jumping upward and catching the airship as an acrobat catches a horizontal bar, then climbs aboard. Note L. A near view of the motionless airship. If the cloud curtain on rollers is used, it may be shown as a background, Scenes 19 and 20 being com- bined. If roller cloud curtain be not available, the view may be so taken that no motion is needed, Johnnie and the near parts of the airship filling the screen, with possibly the aviator also visible. Use the rocking or panoram of camera to simulate the airship's movement. Note M. // bona fide airship is available, no trick flights are required, all pictures being made with the airship at rest except the bona fide start, or a short bona fide view of the airship in flight. If stock negative of an airship in flight is available, it may be used for Scene 17 and the dummy for Scenes 19 and 20 may be of a design in imitation of the airship of Scene 17. SPECIMEN TRAVEL SCRIP As a task for an author, the writing of a scrip for a travel pic- ture is not a long nor a difficult task. It is at most a guidance for the producer. In many cases the author's scrip may be dispensed with altogether, the producer going into the field equipped with the camera only and making photographs of whatever opportunity may offer in the hope of piecing them together to form an acceptable series. The following scrip is a specimen which might be given to a producer as his instruction, with liberty to omit any unduly diffi- cult scene and to add whatever scenes may be offered by chance. 90 W Q eg MOTOGRAPHY 23 TITLE A Trip Across Lake Michigan PLOT A trip beginning in Chicago and ending in South Haven, Michigan, via steamer "Westland," showing something of fruit traffic. SCENARIO Cast of Characters None Scene Sets None Special Synopsis Title: "Chicago River." SCENE 1. Panorama from one of the bridges, showing large passenger steamers at dock, showing particularly the Westland, on which the trip is to be made. SCENE 2. Turning of a bridge and passing through of a large freight boat. SCENE 3. Leaving of the little passenger boat on its frequent trips down the drainage canal. Title: "Away for Vacation Days." SCENE 4. Ticket window, people buying tickets. SCENE 5. Gangplank of steamer, people going aboard. Title: "Leaving the River." SCENE 6. Travel scene from bow of boat, showing opening of Rush Street bridge to let boat through. Better make this with trick handle, half speed. Show also points of interest on banks of river and lighthouse on pier at mouth of river. Title: "Chicago Water Front." SCENE 7. Panorama of Chicago water front. Make this from the outer breakwater, two or three camera stands if necessary. Title: "Out of Sight of Land." SCENE 8. Panorama of waves, showing details of -boat structure, sweep- ing the horizon rapidly from stern of boat to stem without showing land. Title: "South Haven, Michigan, Breakwater." SCENE 9. View from bow of steamer as vessel approaches the mouth of the river. Trick handle probably. Title: "South Haven." SCENE 10. Panorama of South Haven water front. Make from light- house at end of pier. Title: "Oh! There you are!" SCENE 11. Passengers disembarking from boat. Greetings by friends. May require some posing and stock actors. Title: "Off for a Day on the Farm," SCENE 12. 'Bus, loaded, driving down village street, passengers waving to camera man. 91 24 THE MOTION PICTURE Title: "Peaches." SCENE 13. Peach orchards, picking peaches, packing in baskets, haul- ing to town, loading on steamer for Chicago market. Grapes, plums, anything that can be had of the fruit industry. Several scenes. Title: "South Haven Amusements." SCENE 14. Dance pavilion, roller coaster, the little launch on the river loaded with passengers. Several scenes. (End of picture.) The picture-show patrons like the dramas and comedies and as a rule find the travels tiresome. They demand the dramas and make caustic remarks about the dry travels. The theater managers get this sentiment from their patrons and, in turn, take it to the film exchanges, refusing travels sometimes when offered for exhibition. The film exchanges, in turn, carry this sentiment to the manufac- turers. The result is a strange dodge on the part of the film manu- facturers, producing what might be called a travel and drama or travel and comedy. It is produced by combining something of a dramatic or comic nature with the scenery which is to form the sub- ject for the travel picture. SPECIMEN TRAVEL AND COMEDY SCRIP The following is a specimen scrip for such a film picture: TITLE Sammy at Niagara Falls PLOT A scenic review of Niagara Falls. Sammy takes a train and arrives at the Falls. In recording Sammy's adventures at the Falls such scene sets are chosen as to do the falls completely SCENARIO Cast of Characters Sammy, ordinary dress except a comical cap Office help Visitors at Falls for passers-by business Scene Sets Office scene Bedroom, poorly furnished A railway station Another railway station, with sign, "Niagara Falls" Natural scenery at Niagara Falls, New York Synopsis Title: "Sammy is Off for a Vacation." MOTOGRAPHY 25 SCENE 1. Office, with Bookkeeper and Typewriter Operator. Discovered, Sammy, bookkeeper, stenographer, other help. Sammy in great glee, talks to all, serially, makes more confusion than headway with his work, bookkeeper hands him pay envelope, Sammy tears open and takes out money, waves money in glee, gets hat, exit, all stopping work and waving adieu. Title: "Where Shall I Spend My Vacation?" SCENE 2. Bedroom. Enter Sammy, in glee, carrying newspaper. Takes off hat and coat, sits, feet up, reads paper with frowns, suddenly great glee, holds up paper. Title: "Newspaper. Page, showing advertisement, railway to Niagara Falls and return $4.60, tickets good one week." (Back to Scene 2.) Sammy throws down paper, takes hat and coat, takes money from pocket and replaces it, exit. SCENE 3. Railway station platform. Enter Sammy, paces platform impatiently; enter supes and passers-by. Enter train, Sammy gets on board, exit train. SCENE 4. Railway station platform, with station sign "Xiagara Falls." Enter train. Enter passengers leaving train, Sammy last, exit Sammy one side. SCENE 5. Panorama of the Falls, from any convenient elevation, such as balcony at Windsor Hotel, Canadian side. SCENE 6. Prospect Point. Shows American Falls and protecting rail- ing at Prospect Point. After panorama to show scene, when scene is nearly out, enter Sammy with fish pole and begins to bait hook. SCENE 7. The stone bridge. While panoraming the bridge, Sammy nearly gets run over by a rig while walking around in the roadway with a tin cup looking for water, stage business of thirst. SCENE 8. Terrapin Island. View from Goat Island, showing bridge to Terrapin Island, panoraming for view. As view nears end, Sammy comes out half way across Terrapin Bridge with a string on his tin cup, lowers the cup into the water, hauls it up and gets a much satisfying drink. Sc KM: 9. Maid of the Mist. Show boat at dock, and passengers in- cluding Sammy passing aboard, Falls in background. . SCENE 10. Camera on board the Maid of the Mist. Near view of the Falls. Sammy appears at rail in near foreground of camera and is deathly seasick. SCENE 11. Cave of the Winds. Panoram for view, then pick up Sammy and panoram him half way across the bridges between Goat Island and the Cave of the Winds. He becomes afraid and turns back. Again attempts it, but again turns back, this time finally. Camera keeps him in field continu- ously. '(End of Picture.) Such a combination enables the film manufacturer to render his travel pictures more acceptable to that class of patron disliking the travel in its pure form. The exhibitor also has opportunity to advertise the picture in his theater front announcement either as "A Roaring Comic" or as "A Beautiful and Wonderful Nature Picture." 93 26 THE MOTION PICTURE SPECIMEN INDUSTRIAL SCRIP To depict an industry completely sometimes requires pictures taken in various parts of the world. "The Rubber Industry" should begin with views of the tropical rubber trees, curing the sap for shipment and loading on vessels. Then the scene shifts to the northern factory, the processes of bringing the rubber into commercial shape and the manufacture of some well known article wholly or largely composed of rubber. The picture may close with a scene showing manufactured article in. use. The scenes taken inside the factory doubtless would require artificial lighting. An industrial film well done sometimes involves scenes of great difficulty, and even trick pictures. The following specimen scrip calls for the "stop" picture. TITLE Raising Watermelons PLOT Preparing the ground and planting. Then a growing vine by stop pic- ture. Picking, loading, hauling, loading cars, freight train in transit to city, melons on sale in city store front. SCENARIO Title: "Preparing the Ground." SCENE 1. (Select a scene with picturesque background, showing gate from field to highway. Take camera stand to panoram field, gate and high- way, including background objects. Build permanent camera stand, that the identical position of camera may be taken from time to time.) Plowing and fertilizing in the fall. SCENE 2. From same viewpoint, a snowstorm scene. SCENE 3. From same viewpoint, a sleigh passing on the highway. Title: "In the Spring, the Work Begins Again." SCENE 4. From same viewpoint, spring plowing. SCENE 5. Forming the hills for planting. SCENE 6. Planting the seed. Title: "The Growing Plant." SCENE 7. Stop picture, studio. The hand planting the seed, the breaking of the plant through surface of earth, growing hourly to blossom. SCENE 8. Stop picture of field. SCENE 9. Stop picture of near view of melon. Title: "Selecting the Ripe Fruit." SCENE 10. View of field with man working, testing melons for ripeness. As he comes near the camera, his tests are clearly seen, and the cutting of the stem and turning up of the white side is shown. . 04 MOTOGRAPHY 27 Title: "On the Way to Market." SCENE 11. Wagon in field, loading the selected melons. SCENE 12. Panoram loaded wagon through gate and along highway. SCENE 13. Near shipping point, many wagons, all loaded. SCENE 14. Loading the melons into railway cars, showing method of handling. SCENE 15. The melon farmer gets the money at the car door from the shipper. SCENE 16. From the caboose of a railway freight train, showing train ahead and scenery passing by, running through rural district. SCENE 17. Same, entering large city. SCENE 18. City store front, melons on sale. Lady enters and buys. Delivery boy puts purchased melon in basket and exit carrying. (End of Picture.) Who is the Author. Usually, it is the producer. Surely no author is better qualified to write within the limitations of the motion- picture art than the producer. Surely no producer is better able to interpret a story than the author. In industrials, the producer may look over the situation in the capacity of author and write the scrip in memorandum form as his field notes for working with the camera. With the notes in hand, he takes the camera man and equipment and makes the various scenes which his notes show pos- sible or desirable. In travels, comedy, or dramatic accompaniment, the field should be looked over to learn its possibilities, and no one is better qualified than an experienced producer. In current events, an experienced producer is the best judge of advantageous view- points. In chases, the central idea, the joke of the picture, may be sufficient information to pass from the author to the producer, the producer providing scenes to embody the thought in a picture within the limitations of the art and his immediate environment. It is in comedies and dramas that the author as such may be entirely remote from the producer. Scrips for comedy and drama may be written as short stories are written, and may be submitted to film manufacturers as short stories are submitted to magazine publishers. THE PRODUCER The producer is in charge of the studio, of the scene painters, of the sign writers, of the stage carpenters, of the property man, of the actors, and is nominally in charge of the camera men. When the producer undertakes a picture, the scrip is made as complete as he desires by adding details of scenes, notes of probable 95 28 THE MOTION PICTURE location of outdoor scenes, names of actors suitable for the parts or notes on actors required to be found for the parts, as well as notes on other pictures being produced or to be produced contemporane- ously with the scrip being studied. Studio stage sets and scenery required are noted and a property list is made. The titles also are noted, for title making is a part of the work quite distinct from scene making. The producer keeps all his departments running as smoothly as possible, -the motion scenes for a drama being produced this week while titles are being made for another drama for which the motion scenes were produced last week, and the stage carpenters and scene painters are at work upon studio settings and properties for still another drama for which the motion scenes will be produced hi the weeks following. The order of producing drama is: (1~) Painting the scenery for the studio sets, for none but the simplest scene sets are used repeatedly. (2} Getting the properties and costumes. (3) Getting the actors and rehearsing and photographing the motion scenes. (4) Producing the motion scenes before the camera. (5) Inspect- ing the proofs of the motion scenes, retaking unsatisfactory scenes and making additional scenes which may seem desirable some- times, alas, only for v "padding" after the author's scenes have been reviewed. (#) Rewriting the scrip if necessary to fit the drama as embodied in the motion scenes. (7) Writing the titles finally and in detail. ( consists of a plate of zinc immersed in sulphuric acid between two plates of carbon, carbon being used instead of copper because it gives a greater e. m. f. In the sulphuric acid is dissolved some bichromate of potassium or sodium, the function of which is to unite chemically with the hydro- gen as fast as it is formed at the positive plate, thus preventing its accumulation upon this plate.* Such a cell has the high e. m. f. of 2.1 volts. Its internal resistance is low from .2 to .5 ohm since the plates are generally large and close together. It will be seen, therefore, that when the external resistance is very small it is capable of furnishing a current of from 5 to 10 amperes. Since, however, the chromic acid formed by the union of the sulphuric acid with the bi- *To set up a bichromate cell, dissolve 12 parts, by weight, of sodium bichromate in 180 parts of boiling water. After cooling, add 25 parts of commercial sulphuric acid. 226 ELECTRICAL PRINCIPLES 15 chromate attacks the zinc even when the circuit is open, it is neces- sary to lift the zinc from the liquid by the rod A, when the cell is not in use. Such cells are useful where large currents are needed for a short time. The great disadvantages are that the fluid deteriorates rapidly, and that the zinc cannot be left in the liquid. Daniell Cell. The Daniell cell consists of a zinc plate immersed in zinc sulphate, and a copper plate immersed in copper sulphate, the two liquids being kept apart either by means of a porous earthen cup, as in the types shown in Fig. 14, or else by gravity, as in the type shown in Fig. 15. This last type, commonly called the gravity, or Fig. 14. Section of Daniell Cell Danio'l Coll (Commercial Type) crowfoot type, is used almost exclusively on telegraph lines. The copper sulphate, being the heavier of the two liquids, remains at the bottom about the copper plate, while the zinc sulphate remains at the top about the zinc plate. In this cell polarization is almost entirely avoided, for the reason that no opportunity is given for the formation of hydrogen bubbles. For, just as the hydrochloric acid solution consists of positive hydro- gen ions and negative chloride ions in water, so the zinc sulphate (ZnSO 4 ) solution consists of positive zinc ions and negative SO 4 ions. Now the zinc of the zinc plate goes into solution in the zinc sulphate in precisely the same way that it goes into solution in the 227 16 THE MOTION PICTURE hydrochloric acid of the simple cell. This gives a positive charge to the solution about the zinc plate, and causes a movement of the positive ions between the two plates from the zinc toward the copper, and of negative ions in the opposite direction, both the Zn and the SO 4 ions being able to pass through the porous cup. Since the posi- tive ions about the copper plate consist of atoms of copper, it will be seen that the material which is driven out of solution at the copper plate, instead of being hydrogen, as in the simple cell, is metallic copper. Since, then, the element which is deposited on the copper plate is of the same molecular structure as that of which it already consists, it is clear that neither the electromotive force nor the resistance of the cell can be changed by the presence of this deposit, i. e., the cause of the polarization of the simple cell has been removed. The great advantage of the Daniell cell lies in the relatively high degree of constancy in its e. m. f. (1.08 volts). It has a com- paratively high internal resistance one to six ohms and is, therefore, incapable of produc- ing very large currents, about one ampere at most. It will furnish a very constant cur- rent, however, for a great length of time; in fact until all of the copper is driven out of the copper sulphate solution. In order to keep a constant supply of the copper ions in the solution, copper sulphate crystals are kept in the compartment S of the cell of Fig. 14, or in the bottom of the gravity cell. These dissolve as fast as the solution loses its strength through the deposition of copper on Fig. 15. Gravity Cell the CO PP Cr P late ' The Daniell is a so-called closed-circuit cell, i. e., its circuit should be left closed through a resistance of thirty or forty ohms whenever the cell is not in use. If it is left on open circuit, the copper sulphate diffuses through the porous cup, and a brownish muddy deposit of copper or copper oxide is formed upon the zinc. Pure copper is also deposited in the pores of the porous cup. Both of these actions damage the cell. When the circuit is closed, however, since the electrical forces always keep the copper 228 ELECTRICAL PRINCIPLES 17 ions moving toward the copper plate, these damaging effects are to a large extent avoided Leclanche CM. The Leclanche" cell, Fig. 16, consists of a zinc rod in a solution of ammonium chloride 150 g. to a liter of water and a carbon plate placed inside of a porous cup which is packed full of manganese dioxide and powdered graphite or carbon. As in the simple cell, the zinc dissolves in the liquid, and hydrogen is liberated at the carbon, or positive, plate. Here it is slowly attacked by the manganese dioxide. This chemical action is, however, not quick enough to prevent rapid polarization when large currents are taken from the cell. The cell -slowly recovers when allowed to stand for a while on open circuit. The e. m. f. of a Leclanche cell is about 1.5 volts, and its initial internal resistance is somewhat less than an ohm. It, therefore, furnishes a momentary current of from one to three amperes. p . 1(J The immense advantage of this type of cell lies in the fact that the zinc is not at all eaten by the ammonium chloride when the circuit is open, and that, therefore, unlike the Daniell or bichromate cells, it can be left for an indefinite time on open circuit without deterioration. Leclanche" cells are used almost exclusively where momentary currents only are needed, as, for example, on door-bell circuits. The cell requires no attention for years at a time, other than the occasional addition of water to replace loss by evaporation, and the occasional addition of ammo- nium chloride (NH 4 C1) to keep positive NH 4 and negative Cl ions in the solution. Dry Cell. The dry cell is only a modified form of the Leclanche* cell. It is not really dry, since the zinc and carbon plates are im- bedded in moist paste which consists usually of one part of crystals of ammonium chloride, three parts of plaster of Paris, one part of zinc oxide, one part of zinc chloride, and two parts of water. The plaster of Paris is necessary in order to give the paste the re- quired rigidity. As in the Lccjanche' cell, the current is produced by the chemical action of the ammonium chloride upon the zinc plate which forms the outside wall of the cell. 229 18 THE MOTION PICTURE Combinations of Cells. There are two ways in which cells may be combined: First, in series; and second, in parallel. When they are connected in series the zinc of one cell is joined to the copper of the second, the zinc of the second to the copper of the third, etc., the copper of the first and the zinc of the last being joined to the ends of the external resistance, Fig. 17. The e. m. f. of such a combina- tion is the sum of the e. m. f.'s of the single cells. The internal re- sistance of the combination is also the sum of the internal resistances of the single cells. Hence, if the external resistances are very small, the current furnished by the combination will not be larger than that furnished by a single cell, since the total resistance of the circuit has been increased in the same ratio as the total e. m. f. But if the ex- Fig. 17. Cells Connected in Series ternal resistance is large, the current produced by the combination will be very much greater than that produced by a single cell. Just how much greater can always be determined by applying Ohm's law, for if there are n cells in series, and E is the e. m. f. of each cell, the total e. m. f. of the circuit is n E. Hence if R e is the external resist- ance and Ri the internal resistance of a single cell, then Ohm's law gives nE R e + llRi If the n cells are connected in parallel, that is, if all the coppers are connected together and all the zincs, as in Fig. 18, the e. m. f. of the combination is only the e. m. f. of a single cell, while the internal resistance is of that of a single cell, since connecting the cells in n 230 ELECTRICAL PRINCIPLES 19 this way is simply equivalent to multiplying the area of the plates n times. The current furnished by such a combination will be given by the formula c- If, therefore, R e is negligibly small, as in the case of a heavy copper wire, the current flawing through it will be n times as great as that which couid be made to flow through it by a single cell. These considerations show that the rules which should govern the combination of cells are as follows: When the external resistance is large in com- parison with the internal resistance of a single cell, the cells should be connected in series. When the external resistance is small in com- parison with the internal resistance of a single cell, the cells should be connected in parallel. Storage Battery. If two lead plates are immersed in sulphuric acid and the current sent through the cell, the anode or plate at which the current enters the solution will be found in the course of a few minutes to turn dark brown. This brown coat is a compound of lead with the oxygen which, in the case of the platinum electrodes, was evolved as a gas. The other lead plate is not affected by the hydrogen, which is, in this case, as in that of the platinum, evolved as a gas. Since the passage of the current through this cell has left one plate unchanged, while it has changed the surface of the other plate to a new substance, namely, lead peroxide, PbO 2 , it might be expected that if the charging battery were removed, and these two dissimilar plates connected with a wire, a current will flow through the wire, for the arrangement is now essentially a simple galvanic cell, which in its essentials consists simply of two dissimilar plates immersed in an electrolyte a conducting liquid other than a molten metal. In this case the plate having the lead peroxide upon it cor- responds to the copper of an ordinary cell, and the unchanged lead Fi K . 18. Cells Con- nected in Parallel 231 20 THE MOTION PICTURE Fig. 19. Magnetic Prop- erties of a Loop plate to the zinc. The arrangement will furnish a current until the lead peroxide is all used up. The only important difference between a commercial storage cell and the two lead plates just considered, is that the former is provided in the process of manufacture with a very much thicker coat of the active material lead peroxide on the posi- tive plate, and a porous, spongy lead on the negative than can be formed by a single charging such as we considered. In one type of storage cell this active material is actually formed by the repeated charging and discharg- ing of plates which are originally ordinary sheets of lead. With each new charging a slightly thicker layer of the lead peroxide is formed. In the more common type of commer- cial cell the active material is pressed into interstices of the plate in the form of a paste. It will be seen from this discussion that a storage battery is not, properly speaking, a device for storing electricity. It is rather a device in which the electrical cur- rent produces chemical changes, and these new chemicals, so long as they last, are capable of generating a new electrical current. ELECTROMAGNETISM Magnetic Properties of a Loop. We have seen that an elec- trical current is surrounded by a magnetic field the direction of which is given by the right-hand rule. We have seen also that a loop or coil of wire through which a current flows produces a magnetic field of the shape shown in Fig. 7. Now, if such a loop is suspended in the manner shown in Fig. 19 while a current is passed through it, it is found to slowly set itself in an east-and-west plane, and so that the face of the loop from which the magnetic lines emerge, Fig. 20, is toward the north. In other words, the loop will be found to behave with respect Fig 20. Magnetic Properties of a Loop 232 ELECTRICAL PRINCIPLES 21 to the earth or to any other magnet precisely as though it were a flat magnetic disk whose boundary is the wire, the face which turns toward the north, that is, that from which the magnetic lines emerge, being an N pole and the other an S pole. Magnetic Properties of a Helix. If a wire carrying a current be wound in the form of a helix and held near a suspended magnet Fig. 21. Magnetic Properties of a Helix as in Fig. 21, the coil will be found to act in every respect like a mag- net, with an N pole at one end and an 12.6 = !32 2 .I 2 Hence, required resistance = 12. 6 X 2 .32 _ 12.6 X .01 .1024 = 1.23 ohms (approx.) Ans. 1.23 ohms. Specific Resistance. The specific resistance of a substance is the resistance of a portion of that substance of unit length and unit cross-section at a standard temperature. The units commonly used are the centimeter of the inch, and the temperature that of melting ice. The specific resistance may therefore be said to be the resistance (usually stated in microhms) of a centimeter cube or of an inch cube at the temperature of melting ice. If the specific resistances of two substances are known, then their relative resistance is given by the ratio of the specific resistances. Conductivity. Conductivity is the reciprocal of specific resist- ance. EXAMPLE. A certain copper wire at the temperature of melting ice has a resistance of 29.7 ohms. Its specific resistance resistance of 1 centi- meter cube in microhms is 1.594, and that of platinum is 9.032. What would be the resistance of a platinum wire of the same size and length of the copper wire, and at the same temperature? Solution. The resistance would be in direct ratio of the specific resist- ances, and we have the proportion required resistance : 29.7 : : 9.032 : 1.594 Hence, required resistance = 29.7 X 1 .594 = 168 ohms (approx.) Ans. 168 ohms. 238 ELECTRICAL PRINCIPLES 27 Calculation of Resistance. From the preceding pages it is evident that resistance varies directly as the length, inversely as the cross-sectional area, arid depends upon the specific resistance of the material. This may be expressed conveniently by the for- mula in which R is the resistance, L the length of the conductor, A the area of its cross-section, and * the specific resistance of the ma- terial. EXAMPLE. A telegraph relay is wound with 1,800 feet of wire .010 inch in diameter, and has a resistance of 150 ohms. What will be its resist- ance if wound with 40 feet of wire .022 inch in diameter? Solution. If the wires were of equal length, we should have the pro- portion required resistance: 150 : : (.010) 2 : (.022) 2 or, required resistance = 150 X - - 2 = 30.99 + ohms For a wire 400 feet long, we have, therefore, by direct proportion, 400 required resistance = - X 30.99 = 6.88 + Ans. 6.88 + ohms. If a circuit is made up of several different materials joined in series with each other, the resistance of the circuit is equal to the sum of the resistances of its several parts. In calculating the re- sistance of such a circuit, the resistance of each part should first be calculated, and the sum of these resistances will be the total re- sistance of the circuit. In Table I is given the resistance of chemically pure substances at centigrade or 32 Fahrenheit in International ohms. The first column of numbers gives the relative resistances when that cf an- nealed silver is taken as unity. For example, mercury has 62.73 times the resistance of annealed silver. The second and third col- umns give the resistances of a foot of wire .001 inch in diameter, and of a meter of wire 1 millimeter in diameter, respectively. The fourth and fifth columns give respectively the resistance in mi- crohms of a cubic inch and cubic centimeter, that is, the specific re- sistances. 28 THE MOTION PICTURE TABLE I Relative Resistance of Chemically Pure Substances at 32 F. Inter- national Ohms Metals Relative Resist- ance Resistance of a wire 1 foot long .001 in. in diameter Resistance of a vrire 1 m. long 1 mm. in diameter Resistance in Microhms Cubic Inch Cubic Cen- timeter Silver, annealed 1.000 9.023 .01911 .5904 1.500 Copper, annealed 1.063 9.585 .02028 .6274 1.594 Silver, hard drawn 1.086 9.S02 .02074 .6415 1.629 Copper, hard drawn 1.086 9.803 .02075 .6415 1.629 Gold, annealed 1.369 12.35 .02613 .8079 2.052 Gold, hard drawn 1.393 12.56 .02661 .8224 2.088 Aluminum, annealed 1.935 17.48 .03700 1.144 2.904 Zinc, pressed 3.741 33.76 .07143 2.209 5.610 Platinum, annealed 6.022 54.34 .1150 3.555 9.032 Iron, annealed 6.460 58;29 .1234 3.814 9.689 Lead, pressed 13.05 117.7 .2491 7.706 19.58 German silver 13.92 125.5 .2659 8.217 20.87 Platinum-silver alloy (J platinum, f silver) 16.21 146.3 .3097 9.576 24.32 Mercury 62.73 570.7 1.208 37.05 94.06 A very small portion of foreign matter mixed with a metal greatly increases its resistance. An alloy of two or more metals always has a higher specific resistance than that of any of its constituents. For example, the conductivity of silver mixed with 1.2 per cent in volume of gold, will be 59 when that of pure silver is taken as 100. Annealing reduces the resistance of metals. The following examples are given to illustrate the use of Table I in connection with the formula R = s - and to show the appli- A cation of preceding laws. EXAMPLE. From the specific resistance of annealed aluminum as given in the next to the last column of the table, calculate the resistance given in the second column of figures for that substance. Solution. The resistance in microhms of a cubic inch of annealed alumi- num at 32 F. is 1.144, which is equal to .000001144 ohms. The resistance of a wire 1 foot long and .001 inch in diameter is required. According to the formula s = .000001144, L = 1 foot = 12 inches and rd 2 3.1416 X .001 2 T~ 4 A = = .0000007854 sq. in. 240 ELECTRICAL PRINCIPLES 29 Substituting these values in the formula we have 12 R = .000001144 X .0000007854 = 17.48 ohms Ans. 17.48 ohms. EXAMPLE. The resistance in microhms of a cubic centimeter of annealed platinum at 32 F. is 9.032. What is the resistance of a wire of the same substance one meter long and one millimeter in diameter at the same temper- ature? Solution. In the formula for resistance we have the quantities s = 9.032 microhms = .000009032 ohms; L = 1 meter = 100 centimeters; and 7T'/ 2 3.1416 X .I 2 A = = = .007854 sq. cm. the diameter being equal to 1 millimeter = .1 cm. Substituting these values we have R = .000009032 X .007854 = .115 ohm Ans. .115 ohm. EXAMPLE. From Table I the resistance of 1 foot of pure annealed silver wire .001 inch in diameter at 32 F. is 9.023 ohms. What is the resistance of a mile of wire of the same substance .1 inch in diameter at that temperature? Solution. As the resistance of wires is directly proportional to their length and inversely proportional to the squares of their diameters, the re- quired resistance is found by multiplying the resistance per foot by 5,280 and the product by the inverse squares of the diameters. i 001 ) 2 Therefore, R = 9.023 X 5280 X j ' f = 4.76 ohms (approx.) Ans. 4.76 ohms. EXAMPLE. A mile and one-half of an annealed wire of pure iron has a resistance of 46.1 ohms. What would be the resistance of hard-drawn wire of^ pure copper of the same length and diameter, assuming each to be at the temperature of melting ice? Solution. The only factor involved by this example is the relative resist- ance of the two metals. From Table I, annealed iron has 6.460 and hard- drawn copper 1 .086 times the resistance of annealed silver. Hence, the resist- ance of the copper is to that of the iron as 1.086 is to 6.460, and the required resistance is R = 46.1 X , = 7.75 ohms (approx.) 241 Ans. 7.75 ohms. 30 'THE MOTION PICTURE EXAMPLE. If the resistance of a wire 7,423 feet long is 18.7 ohms, what would be its resistance if its length were reduced to 6,253 feet and its cross- section made one half again as large? . Solution. As resistance is directly proportional to the length, and in- versely proportional to the area of the cross-section, the required resistance is 6253 2 R = 18.7 X X = 10.5 ohms (approx.) 7423 3 Ans. 10.5 ohms. Resistance Affected by Heating. The resistance of metals depends upon the temperature, and the resistance is increased by heating. The heating of some substances, among which is carbon, causes a decrease in their resistance. The resistance of the fila- ment of an incandescent lamp when lighted is only about half as great as when cold. All metals, however, have their resistance in- creased by a rise in temperature. The percentage increase in resist- ance with rise of temperature varies with the different metals, and varies slightly for the same metal at different temperatures. The increase is practically uniform for most metals throughout a con- siderable range of temperature. The resistance of copper increases about .4 per cent per degree centigrade, or about .22 per cent degree Fahrenheit. The percentage increase in resistance for alloys is much less than for the simple metals. Standard resistance coils are, there- fore, made of alloys, as it is desirable that their resistance should be as nearly constant as possible. The change in resistance of one ohm per degree rise in tem- perature for a substance is called the temperature coefficient for that substance. Table II gives the temperature coefficients for a few substances. If the resistance of a conductor at a certain temperature is known, the resistance the conductor will have at a higher temperature may be found by multiplying the temperature coefficient for the sub- stance, by the number of degrees increase and by the resistance at the lower temperature, and adding to this result the resistance at the lower temperature. The product of the temperature coefficient by the number of degrees increase gives the increase in resistance of one ohm through that number of degrees, and multiplying this by the number of ohms gives the increase in resistance for the conduc- tor. The result obtained is practically correct for moderate ranges of temperature. 242 ELECTRICAL PRINCIPLES 31 TABLE II Temperature Coefficients RISE IN R. OF 1 OHM WHEN HEATED 1F. 1C. Platinoid .00012 .00022 Platinum-silver .00014 .00025 German silver .00022 .00040 Platinum .0019 .0035 Silver .0021 .0038 Copper, aluminum .0022 .0040 Iron .0026 .0046 The above method of calculating the resistance of conductors at increased temperature is conveniently expressed by the follow- ing formula R 2 = R l (l + at) where R 2 is the resistance at the higher temperature, R l that at the lower temperature, a the temperature coefficient for the sub- stance, and / the number of degrees change. From the preceding formula it follows that if the resistance at the higher temperature is known, that at the lower temperature will be given by the formula R.= 1 +at In calculating resistances at different temperatures, the tem- perature coefficient based on the Fahrenheit scale should be used if the number of degrees change is given in degrees Fahrenheit, and that based on the centigrade scale if given in degrees centi- grade. EXAMPLE. The resistance of a coil of German silver wire at 12? 0. is 1,304 ohms. What would be its resistance at a temperature of 60 ( '.? Solution. From the statement of the example /?, = 1,304, / = 60 - 12 = 48, and from Table II, a = .0004. Substituting these values in the formula /? 2 = R l (1+ at), we have 7? t = 1304 (1 + .0004 X 48) = 1304 X 1.0192 = 1329 ohms (approx.) Ans. 1329 ohms. 243 32 THE MOTION PICTURE TABLE III American Wire Gauge (B. & S.) No. DIAMETER IN Circular Mils Ohms per 1000 Ft. No. Circular Mils Ohms per 1000 Ft. Mils Millim. Mils Millim. 0000 460.00 11.684 211600.0 .051 19 35.89 .912 1288.0 8.617 000 409.64 10.405 167805.0 .064 20 31.96 .812 1021.5 10.566 00 364.80 9.266 133079.4 .081 21 28.46 .723 810.1 13.323 324.95 8.254 105592.5 .102 22 25.35 .644 642.7 16.799 1 289.30 7.348 83694.2 .129 23 22.57 .573 509.5 21.185 2 257.63 6.544 66373.0 .163 24 20.10 .511 404.0 26.713 3 229.42 5.827 52634.0 .205 25 17.90 .455 320.4 33.684 4 204.31 5.189 41742.0 .259 26 15.94 .405 254.0 42.477 5 181.94 4.621 33102.0 .326 27 14.19 -.361 201.5 53.563 6 162.02 4.115 26250.5 .411 28 12.64 .321 159.8 67.542 7 144.28 3.665 20816.0 .519 29 11.26 .286 126.7 85.170 8 128.49 3.264 16509.0 .654 30 10.03 .255 100.5 107.391 9 114.43 2.907 13094.0 .824 31 8.93 .277 79.7 135.402 10 101.89 2.588 10381.0 1.040 32 7.95 .202 63.2 170.765 11 90.74 2.305 8234.0 1.311 33 7.08 .108 50.1 215.312 12 80.81 2.053 6529.9 1.653 34 6.30 .160 39.7 271.583 13 71.96 1.828 5178.4 2.084 35 5.61 .143 31.5 342.443 14 64.08 1.628 4106.8 2.628 36 5.00 .127 25.0 431.712 15 57.07 1.450 3256.7 3.314 37 4.45 .113 19.8 544.287 16 50.82 1.291 2582.9 4.179 38 3.96 .101 15.7 686.511 17 45.26 1,150 2048.2 5.269 39 3.53 .090 12.5 865.046 18 40.30 1.024 1624.1 6.645 40 3.14 .080 9.9 1091.865 EXAMPLE. If the resistance of a copper conductor at 95 F. is 48.2 ohms, what would be the resistance of the same conductor at 40 F. ? Solution. In this case R 2 = 48.2, t = 95 - 40 = 55, and from Table r> II, a = .0022. Substituting these values in the formula R^ = - ^- we have 48.2 48.2 1.121 1 + .0022 X 55 = 43 ohms (approx.) Ans. 43 ohms. Table III gives the resistance of the most common sizes of copper wire according to the American or Brown and Sharpe (B. & S.) gauge. The resistance given is for pure copper wire at a tem- perature of 75 F. or 24 C. The fourth column gives the equiva- lent number of wires each one mil or one-thousandth of an inch in diameter. This is called the size of the wire in circular mil and is equal to the square of the diameter in mils. The fifth column 244 ELECTRICAL PRINCIPLES 33 gives the ohms per thousand feet and the resistance per mile is found by multiplying these values by 5.28. Ordinary commercial copper has a conductivity of about 95 to 97 per cent of that of pure copper. The resistance of commercial wire is, therefore, about 3 to 5 per cent greater than the values given in Table III. The resistance for any metal other* than copper may be found by multiplying the resist- ance given in Table III by the ratio of the specific resistance of the given metal to the specific resistance of copper. Table IV gives the size of the English or Birmingham wire gauge. The B. & S. is, however, much more frequently used in this country. The Brown and Sharpe gauge is a little smaller than the Birmingham for corresponding numbers. TABLE IV Stubs' or Birmingham Wire Gauge (B. W. Q.) DIAMETER IN DIAMETER IN DIAMETER IN No. No. No. Mils MiLlim. Mils Millim. Mils Millim. 0000 454 11.53 8 165 4.19 18 49 1.24 00 380 9.65 10 134 3.40 20 35 0.89 1 300 7.62 12 109 2.77 24 22 0.55 4 2.38 6.04 14 83 2.11 30 12 0.31 6 203 5.16 16 65 1.65 36 4 0.10 EXAMPLES FOR PRACTICE 1. What is the resistance of an annealed silver wire 90 feet long and .2 inch in diameter at 32 R? Ans. .02+ ohm. 2. What is the resistance of 300 meters of annealed iron wire 4 millimeters in diameter when at a temperature of C.? Ans. 2.31 + ohms. 3. What is the resistance of 2 miles of No. 27 (B. & S.) pure copper wire at 75 F.? Ans. 565+ ohms. 4. The resistance of a piece of copper wire at 32 F. is 3 ohms. What is its resistance at 49 F.V Ans. 3.11+ ohms. 5. The resistance of a copper wire at 52 F. is 7 ohms. What is its resistance at 32 F.? Ans. 6.70+ ohms. 6. What is the resistance of 49G ft. of No. 10 (B. & S.) pure copper wire at 45 F.? Ans. .483+ ohms. 245 34 THE MOTION PICTURE TABLE V Primary Cells, Electromotive Force, Resistance, Etc. NAME OF CELL ANODE KATHODE EXCITANT DEPOLARIZER E. M. F IN VOLTS INTERNAL RESIST- ANCE IN OHMS Volta Solution of . (Wollas- Zinc Copper Sulphuric Acid None 1 to 0.5 ton, etc.) (H 2 SO 4 ) Solution of Smee Zinc Platinized Silver Sulphuric Acid (H 2 S0 4 ) None 1 to 0.5 0.5 Solution of Law Zinc Carbon Sulphuric Acid (H 2 S0 4 ) None 1 to 0.5 Poggen- dorff (Grenet) Zinc Graphite (Carbon) Solution of Sulphuric Acid (H 2 S0 4 ) Potassium Dichromate (K 2 Cr 2 7 ) 2.1 Poggen- clorfl (Grenet) two fluid Zinc Graphite (Carbon) Saturated Solu- tion of Potas- sium Bichro- mate and Sulphuric Acid None Separate 1.98 .001 to .08 Grove Zinc Platinum Sulphuric Acid dilute (H 2 SO 4 ) Nitric Acid (HNO 3 ) 1.96 0.1 to 0.12 Bunsen Zinc Graphite (Carbon) Sulphuric Acid dilute (H 2 SO 4 ) Nitric Acid l.StOl.98 O.ORtoO.ll Chromic Acid 1.8 0.1 to 0.12 Leclanch6 Graphite (Carbon) Ammonium Chloride (NH 4 C1) Manganese Dioxide (Mn0 2 ) 1.4 to l.C 1.13 to 1.15 Lalande Lalande- Chaperon Zinc Graphite (Carbon) Caustic Potash or Potassium Hydrate (KOH) Cupric Oxide 0.8 to 0.9 1.3 Upward Zinc Graphite (Carbon) Zinc Chloride (ZnCl 2 ) Chlorine (Cl) 2.0 Sodium&Potas- Fitch Zinc Graphite (Carbon) Ammonium Chloride (NH 4 C1) sium Chlorates (NaC10 3 + KC10 3 ) 1.1 Papst Iron Graphite (Carbon) Ferric Chloride (Fe 2 Cl e ) [(Fe 2 Cl ) 0.4 Ammonium Chloride Manganese Obach (dry) Zinc Graphite (Carbon) (NH 4 C1) in Calcium Sul- Dioxide (MnO 2 ) 1.4G phate (CaSO 4 ) Daniell (Meidin- ger Min- Zinc Copper Zinc Sulphate (ZnS0 4 ) Copper Sul- phate (CuSO 4 ) 1.079 2 to 5 otto, etc.) De la Rue Zinc Silver Ammonium Chloride Silver Chloride (AgCl) 1.03 to 1.42 0.4 to 0.6 Marie Davy Zinc Graphite (Carbon) Sulphuric Acid dilute (H 2 S0 4 ) Paste of Sul- phate of Mercury (Hg 2 S0 4 ) 1 52 0.75101 Clark (Standard) Zinc Mercury Zinc Sulphate (ZnSo 4 ) Mercurous Sul- phate(Hg 2 SO 4 ) 1.434* 0.3 to 0.5 Weston Cadmium Mercury Cadmium Sul- phate (CdSO^) Mercurous Sul- hate(HgjjS0 4 ) 1.025 *At 15 degrees centigrade or 59 degrees Fahrenheit. 246 ELECTRICAL PRINCIPLES TABLE V (Continued) 35 NAME OF CELL A NODE KATHODE EXCITANT DEPOLARIZER E. M. F. IN VOLTS INTERNAL RESIST- ANCE IN OHMS Von Helmholtz Zinc Mercury Zinc Chloride (ZnCl 2 ) Mercurous Chloride (Hg 2 Cl 2 ) 1.0 Chromic Acid single fluid Zinc Graphite (Carbon) Sulphuric and Chromic Acids, dilute mixed None Separate 2.2 .016 to .08 Fuller Zinc Graphite (Carbon) Sulphuric Acid (H 2 S0 4 ) Potassium Dichromate (K 2 Cr 2 7 ) 2.0 0.5 to 0.7 Gaiffe Zinc Silver Zinc Chloride (ZnCl 2 ) Silver Chloride (AgCl) 1.02 0.5 to 0.6 Maiche Zinc scraps in bath of Mercury Platinized Carlxm Common Salt Solution i. e. Sodium Chlo- ride (NaCl) None Separate 1.25 1 to 2 Niaudet Zinc Graphite (Carbon) Common Salt Solution t. e. Sodium Chlo- ride (NaCl) Chloride of Calcium (Lime) (CaCl 2 ) 1.0 to 1.6 5 to 6 Schans- chieff Zinc Graphite (Carbon) Mercurial Solution None Separate 1.56 0.05to0.75 Skrivan- off Zinc Silver Caustic Potash or Potassium Hylrato(KOH> Chloride of Silver (AgCl) 1.5 1.5 Resistances in last column measured in cells standing 6" X 4" Table V discloses among other data the resistance of various primary cells. The resistance of a circuit of which a battery forms a part is made up of the external resistance, or the resistance of out- side wires and connections, and the internal resistance, or the resist- ance of the battery itself. The terms anode and kathode appearing in the second and third columns, are commonly used with reference to electrolysis but may also be applied to primary cells. The current passes from the anode to the kathode through the cell and, therefore, with reference to the cell itself, the anode may be considered the posi- tive element and the kathode the negative element. In regard to the outside circuit, however, the current passes, of course, from the kath- ode to the anode, and hence with reference to the outside circuit the kathode is positive and the anode negative; ordinarily, the external circuit is considered. As the anode of almost all primary cells is zinc it may readily be remembered that the current passes from the other element to the zinc through the external circuit. 247 36 THE MOTION PICTURE APPLICATIONS OF OHM'S LAW Ohm's law is one of the most important and most used laws of electricity. Current is directly proportional to the electromotive force and inversely proportional to the resistance. That is, if the electromotive force applied to a circuit is increased, the current will be increased in the same proportion, and if the resistance of a circuit is increased, then the current will be decreased proportionally. Likewise a decrease in the electromotive force causes a proportional decrease in current, and a decrease in resistance causes a proportional increase in current. The current depends only upon the electromotive force and resistance and in the manner expressed by the above simple law. The law may be expressed algebraically as follows electromotive force current a _ resistance The units of these quantities, the ampere, volt, and ohm, have been so chosen that an electromotive force of 1 volt applied to a resistance of 1 ohm, causes 1 ampere of current to flow. Ohm's law may, therefore, be expressed by the equation c- E ~~R where C is the current in amperes, E the electromotive force in volts, and R the resistance in ohms. It is, therefore, evident that if the electromotive force and re- sistance are known the current may be found, or if any two of the three quantities are known the third may be found. If the current and resistance are known the electromotive force may be found from the formula E= RC and if the current and electromotive force are known, the resist- ance may be found from the formula Simple Applications. The following examples are given to illustrate the simplest applications of Ohm's law: 248 ELECTRICAL PRINCIPLES 37 EXAMPLE. If the e. m. f. applied to a circuit is 4 volts and its resist- ance is 2 ohms, what current will flow? Solution. By the formula for current E 4 C = = = 2 amperes R 2 Ans. 2 amperes. EXAMPLE. What voltage is necessary to cause a current of 23 amperes to flow through a resistance of 820 ohms? Solution. By the formula for e. m. f., E = RC = 820 X 23 = 18,860 volts. Ans. 18,360 volts. EXAMPLE. The e. m. f. applied to a circuit is 110 volts, and it is desired to obtain a current of .6 ampere. What should be the resistance of the circuit? Solution. By the formula for resistance R = = = 183. + ohms. C .6 Ans. 183+ ohms. Series Circuits. A circuit made up of several parts all joined in series with each other, is called a series circuit and the resistance of the entire circuit is, of course, the sum of the separate resistances. In calculating the current in such a circuit the total resistance must first be obtained, and the current may then be found by dividing the applied or total e. m. f. by the total resistance. This is expressed by the formula ~ ^ + R 2 + R 3 + etc. EXAMPLE. Three resistance coils are connected in series with each other and have a resistance of 8, 4 and 17 ohms respectively. What current will flow if the e. m. f. of the circuit is 54 volts? Solution. By the preceding formula E 54 54 = /e i + 3 -f*T 8 + 4 + 17 = ^= Ans. 1.8+ amperes. EXAMPLE. Six arc lamps, each having a resistance of 5 ohms, are con- nected in series with each other and the resistance of the connecting wires and other apparatus is 3.7 ohms. What must be the pressure of the circuit to give a desired current of 9.6 amperes? Solution. The total resistance of the circuit is R = (6 X 5) + 3.7 = 33.7 ohms and the current is to be C = 9.6 amperes. Hence, by the formula for e. m. f., E = R C = 33.7 X 9.6 = 323. + volts. Ans. 323 + volts. 249 38 THE MOTION PICTURE EXAMPLE. The current passing in a certain circuit was 12 amperes and the e. m. f . was 743 volts. The circuit was made up of 4 sections all connected in series, and the resistance of three sections was 16, 9, and 26 ohms, respect- ively. What was the resistance of the fourth section? Solution. Let x = the resistance of the fourth section, then R = 16 + 9 + 26 + x = 51 + x, C = 12, and E = 743. By the formula for resistance W 74-^ R or, 51 + x = = 61.9 ohms (approx.) C 12 If 51 + x = 61.9 we have, by transposing 51 to the other side of the equation x = 61.9 - 51 = 10.9 ohms Ans. 10.9 ohms. EXAMPLE. A current of 54 amperes flowed through a circuit when the e. m. f. was 220 volts. What resistance should be added in series with the circuit to reduce the current to 19 amperes? Solution. The resistance in the first case was R = = 4.07 ohms (approx.) The resistance in the second must be 220 R = = 11. 58 ohms (approx.) The required resistance to insert in the circuit is the difference of these two resistances, or 11.58 4.07 = 7.51 ohms. Ans. 7.51 ohms. Fall of Potential in a Circuit* Fig. 28 illustrates a series circuit in which the resistances A, B, C, D, and E are connected in series WWW\A c Fig. 28. Battery Circuit Through Resistances in Series with each other and with the source of. electricity. If the e. m. f. is known, the current may be found by dividing the e. m. f. by the sum of all the resistances. Ohm's law may, however, be applied to any 250 ELECTRICAL PRINCIPLES 39 part of a circuit separately, as well as to the complete circuit. Sup- pose the resistances of A, B, C, D, and E are 4, 3, 6, 3, and 4 ohms, respectively, and assume that the source has no resistance. Suppose the current flowing to be 12 amperes. The e. m. f. necessary to force a current of 12 amperes through the resistance A of 4 ohms is, by applying Ohm's law, equal to E = R C = 4 X 12 = 48 volts. Hence, between the points a and b outside of the resistance A, there must be a difference of potential of 48 volts to force the current through this resistance. Also to force the same current through B, the volt- age necessary is 3 X 12 = 36. Similarly, for each part C, D, and E, there are required 72, 36, and 48 volts, respectively. As 48 volts are necessary for part A and 36 volts for part B, it is evident that to force the current through both parts a differ- ence of potential of 48 + 36 = 84 volts is required; that is, the voltage between the points a and c must be 84 volts. For the three parts A, B, and C, 48 + 36 + 72 = 156 volts are necessary, and for the entire circuit, 240 volts must be applied to give the current of 12 amperes. From the above it is evident that there is a gradual fall of potential throughout the circuit, and if the voltage between any two points of the circuit be measured, the e. m. f. obtained would depend upon the resistance included between these two points. For example, the voltage between points b and d would be found to be 72 + 36 = 108 volts, or between d and c, 36 volts, etc. From the preceding it is apparent that the fall of potential in a part of a circuit is equal to the current multiplied by the resistance of that part. This gradual fall of potential, or drop as it is commonly called, throughout a circuit, enters into the calculations for the size of conduct- ors or mains supplying current to distant points. The resistances of the conductors cause a certain drop in transmitting the current, depending upon their size and length, and it is, therefore, necessary that the voltage of machines at the supply station shall be great enough to give the voltage necessary at the receiving stations as well as the additional voltage lost in the conducting mains. For example, in Fig. 28 the voltage necessary between the points e and b is 144 volts, but to give this voltage the source must supply in addition the voltage lost in parts A and E, which equals 06 volts. 251 40 THE MOTION PICTURE EXAMPLE. The voltage required by 17 arc lamps connected in series is 782 volts and the current is G.6 amperes. The resistance of the connecting wires is 7 ohms. What must be the e. m. f. applied to the circuit? Solution. The drop in the connecting wires isE=RC = 7X 6.6 = 46.2 volts. The e.m.f. necessary is, therefore, 782 + 46.2 = 828.2 volts. Ans. 828.2+ volts. EXAMPLE. The source of e. m. f. supplies 114 volts to a circuit made up of incandescent lamps and conducting wires. The lamps require a voltage of 110 at their terminals, and take a current of 12 amperes. What should be the resistance of the conducting wires in order that the lamps will receive the necessary voltage? Solution. The allowable drop in the conducting wires is 114 110 = 4 volts. The current to pass through the wires is 12 amperes. Hence, the resistance must be E 4 R = = -= .33+ ohms C 12 Ans. .33 ohms. Divided Circuits. When a circuit divides into two or more parts, it is called a divided circuit and each part will transmit a portion of the current. Such a circuit is illustrated in Fig. 29, the two branches being represented by b and c. The current passes from the positive pole of the battery through a and then divides; part of the current passing Fig. 29. Divided Circuits through b and part through c. The current then unites and passes through d to the negative pole of the battery. The part c may be considered as the main part of the circuit and b as a by-pass about it. A branch which serves as a by-pass to another circuit is called a shunt circuit, and the two branches are said to be connected in parallel. In considering the passage of a current through a circuit of this sort, it may be necessary to determine how much current will pass through one branch and how much through the other. Evidently this will depend upon the relative resistance of the two branches, and more current will pass through the branch offering the lesser 252 ELECTRICAL PRINCIPLES 41 resistance than through the branch having the higher resistance. If the two parts have equal resistances, then one-half of the total cur- rent will pass through each branch. If one branch has twice the resistance of the other, then only one-half as much of the total cur- rent will pass through that branch as through the other; that is, one- third of the total current will pass through the first branch and the remaining two-thirds will pass through the second. The relative strength of current in the two branches mill be in- versely proportional to their resistances, or directly proportional to their conductances. Suppose the resistance of one branch of a divided circuit is r p Fig. 30, and that of the other is r r Then by the preceding law current in r l : current in r 2 : : r 2 : r l Also, current in r l : total current : : r 2 : r l + r 2 and current in r 2 : total current : : r l : r l + r 2 Let C represent the total current, i, the current through the resistance r t and i 2 the current through the resistance r v Then the Fig. 30. Joint Resistance of a Divided Circuit two preceding proportions are expressed by the following formulas Cr 2 0, and t, = r, + r 2 r, + r, EXAMPLE. The total current passing in a circuit is 24 amperes. The circuit divides into two branches having resistances of 5 and 7 ohms, respect- ively. What is the current in each branch? Solution. In this case C = 24, r t = 5, and r 2 = 7. Substituting these values in the above formulas, we have 7r 2 24 X 7 = 14 amperes r 2 5 + 7 7r t 24 X 5 and i, = * = = 10 amperes r i + r 2 7 + 7 . j In 5 ohm branch, 14 amperes. In 7 ohm branch, 10 amperes. 253 42 THE MOTION PICTURE Joint Resistance of Divided Circuits. As a divided circuit offers two paths to the current, it follows that the joint resistance of the two branches will be less than the resistance of either branch alone. The ability of a circuit to conduct electricity is represented by its conductance, which is the reciprocal of resistance; and the conduct- ance of a divided circuit is equal to the sum of the conductances of its parts. For example, in Fig. 30, the conductance: of the upper branch equals and that of the lower branch equals . If R represents r i r 2 the joint resistance of the two parts then the joint conductance equals R ^ r 2 r,r 2 Having thus obtained the joint conductance, the joint resist- ance is found by taking the reciprocal of the conductance, that is, r. r, This formula may be stated as follows: The joint resistance of a divided circuit is equal to the product of the two separate resistances divided by their sum. For example, suppose the resistance of each branch to be 2 ohms. The conductance of the circuit will be, = + = 1, and hence R = 1 ohm R 2 2 Also by the preceding formula R = ^1 = 1 ohm 2 + 2 The resistance of a divided circuit in which each branch has a resistance of 2 ohms is, therefore, 1 ohm. EXAMPLE. The resistances of two separate conductors are 3 and 7 ohms, respectively. What would be their joint resistance if connected in parallel? Solution. In this case r l = 3 and r 2 = 7, hence, by the formula R = = 2.1 ohms. 3 + 7 254 Ans. 2.1 ohms. ELECTRICAL PRINCIPLES 43 Suppose, as illustrated in Fig. 31, the conductors having resistances equal to r v r 2 , and r a , respectively, are connected in parallel. The joint total conductance will then be equal to and as the joint resistance is the reciprocal of the joint conductance, the joint resistance R of the three branches is expressed by the formula B r, r, + r, r. + r. r n EXAMPLE. What is the joint resistance when connected in parallel, of three wires whose respective resistances are 41, 52, and 29 ohms, respectively? Solution. In this case r, = 41, r 2 = 52, and r a = 29. Hence, by the preceding formula, 41 X 52 X 29 12.8+ ohms. 52 X 29 + 41 X 29 -I- 41 X 52 Ans. 12.8+ ohms. In general, for any number of conductors connected in parallel, the joint resistance is found by taking the reciprocal of the sum of the reciprocals of the separate resistances. Fig. 31. Triply Divided Circuit EXAMPLE. A circuit is made up of five wires connected in parallel, and their separate resistances are respectively 12, 21, 28, 8, and 42 ohms. What is the joint resistance? Solution. The sum of the conductances is- _L J_ _L _L i 53 ^12 + 21 + 28 + 8 + 42 168 Hence the joint resistance equals 168 R - = 3.1+ ohms 5J Ans. 3.1 + ohms. If the resistance of each branch is known and also the poten- tial difference between the points of union, then the current in each branch may be found by applying Ohm's law to each branch sepa- rately. For example, if this potential difference were 96 volts, 255 44 THE MOTION PICTURE and the separate resistances of the 4 branches were 8, 24, 3, and 48 ohms, respectively, then the current in the respective branches would be 12, 4, 32, and 2 amperes, respectively. If the current in each branch is known, and also the potential difference between the points of union, then the resistance of each branch may likewise be found from Ohm's law. The following examples are given to illustrate the application of the preceding principles. EXAMPLES FOR PRACTICE 1. Two conductors having resistances of 71 and 19 ohms, respectively, are connected in parallel, and the total current pass- ing in the circuit is 37 amperes. What current passes in the con- ductor whose resistance is 71 ohms? Ans. 7.$+ amperes. 2. What is the joint resistance of two wires connected in parallel if their separate resistances are 2 and 8 ohms, respectively? Ans. 1.6 ohms. 3. What is the joint resistance of three wires when connected in parallel, whose separate resistances are 5, 7, and 9 ohms, re- spectively? Ans. 2.2+ ohms. 4. Three wires, the respective resistances of which are 8, 10, and 20 ohms, are joined in parallel. What is their joint resistance? Ans. 3.6+ ohms. 5. Four wires are joined in parallel, and their separate re- sistances are 2, 4, 6, and 9 ohms, respectively. What is the joint resistance of the conductor thus formed? Ans. .97+ ohms. WIRING METHODS PLANNING AN INSTALLATION The first step in planning a wiring installation, is to gather all tne data which will affect cither directly or indirectly the system of wiring and the manner in which the conductors are to be installed. The data will include: Kind of building; construction of building; space available for conductors; source and system of electric-current supply; and all details which will determine the method of wiring to be employed. These last items materially affect the cost of the work, and are usually determined by the character of the building and by commercial considerations. 250 ELECTRICAL PRINCIPLES 45 Method of Wiring. In a modern fireproof building, the only system of wiring to be recommended is that in which the conductors are installed in rigid conduits; although, even in such cases, it may be desirable, and economy may be effected thereby, to install the larger feeder and main conductors exposed on insulators using weather- proof slow-burning wire. This latter method should be used, how- ever, only where there is a convenient runway for the conductors, so that they will not be crowded and will not cross pipes, ducts, etc., and also will not have too many bends. Also, the local inspection authori- ties should be consulted before using this method. For mills, factories, etc., wires exposed on cleats or insulators are usually to be recommended, although rigid conduit, flexible con- duit, or armored cable may be desirable. In finished buildings, and for extensions of existing outlets, where the wiring could not readily or conveniently be concealed, moulding is generally used, particularly where cleat wiring or other exposed methods of wiring would be objectionable. However, as has already been said, moulding should not be employed where there is any liability to dampness. In finished buildings, particularly where they are of frame con- struction, flexible steel conduits or armored cable are to be recom- mended. While in new buildings of frame construction, knob and tube wiring is frequently employed, this method should be used only where the question of first cost is of prime importance. While ar- mored cable will cost approximately 50 to 100 per cent more than knob and tube wiring, the former method is so much more perma- nent and is so much safer that it is strongly recommended. Systems of Wiring. The system of wiring that is, whether the two-wire or the three-wire system shall be used is usually deter- mined by the source of supply. If the source of supply is an isolated plant, with simple two-wire generators, and with little possibility of current being taken from the outside at some future time, the wiring in the building should be laid out on the two-wire system. If, on the other hand, the isolated plant is three-wire (having three-wire generators, or two-wire generators with balancer sets), or if the cur- rent is taken from an outside source, the wiring in the building should be laid out on a three-wire system. 257 46 THE MOTION PICTURE It very seldom happens that current supply from a central station is arranged with other than the three-wire system inside of buildings, because, if the outside supply is alternating current, the transformers are usually adapted for a three-wire system. For small buildings, on the other hand, where there are only a few lights and where there would be only one feeder, the two-wire system is used. As a rule, however, when the current is taken from an outside source, it is best to consult the engineer of the central station supplying the current, and to conform with his wishes. As a matter of fact, this should be done in any event, in order to ascertain the proper voltage for the lamps and for the motors, and also to ascertain whether the central station will supply transformers, meters, and lamps, for, if these are not thus supplied, they should be included in the contract for the wiring. Location of Outlets. A set of plans, including elevation and details, if any, and showing decorative treatment of the various rooms, should be obtained from the architect. A careful study should then be made by the architect, the owner, and the engineer, or some other person qualified to make recommendations as to illumination. The location of the outlets will depend: First, upon the decorative treatment of the room, which determines the aesthetic and architect- ural effects; second, upon the type and general form of fixtures to be used, which should be previously decided on; third, upon the tastes of the owners or occupants in regard to illumination in general, as it is found that tastes vary widely in regard to amount and kind of illumination. The .location of the outlets, and the number of lights required at each, having been determined, the outlets should be marked on the plans. The architect should then be consulted as to the location of the centers of distribution, the available points for the risers or feeders, and the available space for the branch circuit conductors. In regard to the rising points for the feeders and mains, the fol- lowing precautions should be used in selecting chases: The space should be amply large to accommodate all the feeders and mains likely to rise at that given point. This seems trite and unnecessary but it is the most usual trouble with chases for risers. Formerly architects and builders paid little attention to the requirements for chases for electrical 258 ELECTRICAL PRINCIPLES 47 work; but in these later days of 2-inch and 2^-inch conduit, they realize that these pipes are not so invisible and mysterious as the force they serve to dis- tribute, particularly when twenty or more such conduits must be stowed away in a building where no special provision has been made for them. If possible, the space should be devoted solely to electric wiring. Steam pipes are objectionable on account of their temperature; and these and all other pipes are objectionable in the same space occupied by the electrical conduits, for if the space proves too small, the electric conduits are the first to be crowded out. The chase, if possible, should be continuous from the cellar to the roof, or as far as needed. This is necessary in order to avoid unnecessary bends or elbows, which are objectionable for many reasons. In similar manner, the location of cut-out cabinets or distributing centers should fulfill the following requirements: They should be accessible at all times. They should be placed sufficiently close together to prevent the circuits from being too long. They should not be placed in too prominent a position, as that is objec- tionable from the architect's point of view. They should be placed as near as possible to the rising chases, in order to shorten the feeders and mains supplying them. Finished Floor- ?ou.gh Flooring/ Sle Cement and Ashes Fig. 32. Running Conductors Concealed Under Floor in Fireproof Building Having determined the system and method of wiring, the location of outlets and distributing centers, the next step is to lay out the branch circuits supplying the various outlets. Before starting to lay out the branch circuits, a drawing showing the floor construction, and showing the space between the top of the beams and girders and the flooring, should be obtained from the archi- tect. In fireproof buildings of iron or steel construction, it is almost the invariable practice, where the work is to be concealed, to run the conduits over the beams, under the rough flooring, carrying them between the sleepers when running parallel to the sleepers, and notch- ing the latter when the conduits run across them, Fig. 32. In wooden 259 48 THE MOTION PICTURE frame buildings, the conduits run parallel to the beams and to the furring, Fig. 33; they are also sometimes run below the beams. In the latter case the beams have to be notched, and this is allowable only in certain places, usually near the points where the beams are sup- ported. The architect's drawing is, therefore, necessary in order that the location and course of the conduits may be indicated on the plans. The first consideration in laying out the branch circuit is the number of outlets and number of lights to be wired on any one branch circuit. The Rules of the National Electric Code require that "no set of incandescent lamps requiring more than 660 watts, whether grouped on one fixture or on several fixtures or pendents, will be dependent on one cut-out." While it would be possible to have branch circuits supplying more than 660 watts, by placing various cut-outs at different points along the route of the branch circuit, so as to subdivide it into small sections to comply with the rule, this method is not recommended, except in certain cases, for exposed wiring in factories or mills. As a rule, the proper method is to have the cut-outs located at the center Stud or Wall Finished Floor^ Stud or Wall Wooden Beam x Furring Strips -^^_ ISE^ KSfrtl Rough Flooring /Conduit Lathing / "^Plastering Fig. 33. Running Conductors Concealed Under Floor in Wooden Frame Building of distribution, and to limit each branch circuit to 660 watts, which corresponds to twelve or thirteen 50-watt lamps, twelve being the usual limit. Attention is called to the fact that the inspectors usually allow 50 watts for each socket connected to a branch circuit; and although 8-candle-power lamps may be placed at some of the outlets, the inspectors hold that the standard lamp is approximately 50 watts, and for that reason there is always the likelihood of a lamp of that capacity being used, and their inspection is based on that assumption. Therefore, to comply with the requirements, an allowance of not more than twelve lamps per branch circuit should be made. 260 ELECTRICAL PRINCIPLES 49 In ordinary practice, however, it is best to reduce this number still further, so as to make allowance for future extensions or to in- crease the number of lamps that may be placed at any outlet. For this reason, it is wise to keep the number of the outlets on a circuit at the lowest point consistent with economical wiring. It has been proven by actual practice, that the best results are obtained by limit- ing the number to five or six outlets on a branch circuit. Of course, where all the outlets have a single light each, it is frequently neces- sary, for reasons of economy, to increase this number to eight, ten, and, in some cases, twelve outlets. Now, as to the course of the circuit work, little need be said, as it is largely influenced by the relative position of the outlets, cut- outs, switches, etc. Between the cut-out box and the first outlet, and between the outlets, it will have to be decided, however, whether the circuits shall run at right angles to the walls of the building or room, or whether they shall run direct from one point to another, irrespective of the angle they make to the sleepers or beams. Of course, in the latter case, the advantages are that the cost is some- what less and the number of elbows and bends is reduced. If the tubes are bent, however, instead of using elbows, the difference in cost is usually very slight, and probably does not compensate for the disadvantages that would result from running the tubes diagonally. As to the number of bends, if branch circuit work is properly laid out and installed, and a proper size of tube used, it rarely happens that there is any difference in "pulling" the branch circuit wires. It may happen, in the event of a very long run or one having a large number of bends, that it might be advisable to adopt a short and more direct route. Up to this time, the location of the distribution centers has been made solely with reference to architectural considerations; but they must now be considered in conjunction with the branch circuit work. It frequently happens that, after running the branch circuits on the plans, we find, in certain cases, that the position of centers of distribution may be changed to advantage, or sometimes certain groups may be dispensed with entirely and the circuits run to other points. We now see the wisdom of ascertaining from the architect where cut-out groups may be located, rather than selecting particular points for their location. 261 50 THE MOTION PICTURE As a rule, wherever possible, it is wise to limit the length of each branch circuit to 100 feet; and the number and location of the dis- tributing centers should be determined accordingly. It may be found that it is sometimes necessary and even desirable to increase the limit of length. One instance of this may be found in hall or corridor lights in large buildings. It is generally desirable, in such cases, to control the hall lights from one point; and, as the number of lights at each outlet is generally small, it would not be economical to run mains for sub-centers of distribution. Hence, in instances of this character, the length of runs will frequently exceed the limit named. In the great majority of cases, however, the best results are obtained by limiting the runs to 90 or 100 feet. There are several good reasons for placing such a limit on the length of a branch circuit. To begin with, assuming that we are going to place a limit on the loss in voltage (drop) from the switchboard to the lamp, it may easily be proven that up to a certain reasonable limit it is more economical to have a larger number of distributing centers and shorter branch circuits, than to have fewer centers and longer circuits. It is usual, in the better class of work, to limit the loss in voltage in any branch circuit to approximately one volt. As- suming this limit (one volt loss), it can readily be calculated that the number of lights at one outlet which may be connected on a branch circuit 100 feet long (using No. 14 B. & S. wire), is four; or in the case of outlets having a single light each, five outlets may be con- nected on the circuit, the first being 60 feet from the cut-out, the others being 10 feet apart. These examples are selected simply to show that, if the branch circuits are much longer than 100 feet, the loss must be increased to more than one volt, or else the number of lights that may be con- nected to one circuit must be reduced to a very small quantity, pro- vided, of course, the size of the wire remains the same. Either of these alternatives is objectionable the first, on the score of regulation; and the second, from an economical standpoint. If, for instance, the loss in a branch circuit with all the lights turned on -is four volts (assuming an extreme case), the voltage at which a lamp on that circuit burns will vary from four volts, depending on the number of lights burning at a time. This, of course, will cause the lamp to burn below candle-power when all the lamps are turned on, ELECTRICAL PRINCIPLES 51 or else to diminish its life by burning above the proper voltage when it is the only lamp burning on the circuit. Then, too, if the drop in the branch circuits is increased, the sizes of the feeders and the mains must be correspondingly increased (if the total loss remains the same), thereby increasing their cost. If the number of lights on the circuit is decreased, we do not use to good advantage the available carrying capacity of the wire. Of course, one solution of the problem would be to increase the size of the wire for the branch circuits, thus reducing the drop. This, however, would not be desirable, except in. certain cases where there were a few long circuits, such as for corridor lights or other special control circuits. In such instances as these, it would be better to increase the sizes of the branch circuit to No. 12 or even No. 10 B. &. S. gauge conductors, than to increase the numbers of centers of distribution for the sake of a few circuits only, in order to reduce the number of lamps (or loss) within the limit. The method of calculating the loss in conductors has been given elsewhere; but it must be borne in mind, in calculating the loss of a branch circuit supplying more than one outlet, that separate calcu- lations must be made for each portion of the circuit. That is, a calculation must be made for the loss to the first outlet, the length in this case being the distance from the center of distribution to the first outlet, and the load being the total number of lamps supplied by the circuit. The next step would be to obtain the loss between the first and second outlet, the length being the distance between the two out- lets, and the load, in this case, being the total number of lamps sup- plied by the circuit, minus the number supplied by the first outlet; and so on. The loss for the total circuit would be the sum of these losses for the various portions of the circuits. Feeders and Mains. If the building is more than one story, an elevation should be made showing the height and number of stories. On this elevation, the various distributing centers should be shown diagrammatically; and the current in amperes supplied through each center of distribution, should be indicated at each center. The next step is to lay out a tentative system of feeders and mains, and to ascertain the load in amperes supplied by each feeder and main. The estimated length of each feeder and main should then be deter- mined, and calculation made for the loss from the switchboard to 263 52 THE MOTION PICTURE each center of distribution. It may be found that in some cases it will be necessary to change the arrangement of feeders or mains, or even the centers of distribution, in order to keep the total loss from the switchboard to the lamps within the limits previously determined. As a matter of fact,. in important work, it is always best to lay out the entire work tentatively in a more or less crude fashion, according to the "cut-and-dried" method, in order to obtain the best results, be- cause the entire layout may be modified after the first preliminary layout has been made. Of course, as one becomes more experienced and skilled in these matters, the final layout is often almost identical with the first preliminary arrangement. WIRING AN OFFICE BUILDING The building selected as a typical sample of a wiring installation is that of an office building located in Washington, D. C. The figures shown are reproductions of the plans actually used in installing the work. The building consists of a basement and ten stories. It is of fireproof construction, having steel beams with terra-cotta flat arches. The main walls are of brick and the partition walls of terra-cotta blocks, finished with plaster. There is a space of approximately five inches between the top of the iron beams and the top of the finished floor, of which space about 3 inches was available for running the electric conduits. The flooring is of wood in the offices, but of concrete, mosaic, or tile in the basement, halls, toilet-rooms, etc. The electric current supply is derived from the mains of the local illuminating company, the mains being brought into the front of the building and extending to a switchboard located near the center of the basement. % As the building is a very substantial fireproof structure, the only method of wiring considered was that in which the circuits would be installed in iron conduits. Electric Current Supply. The electric current supply is direct current, two-wire for power, and three-wire for lighting, having a potential of 236 volts between the outside conductors, and 118 volts between the neutral and either outside conductor. Switchboard. On the switchboard in the basement are mounted wattmeters, provided by the local electric company, and the various ELECTRICAL PRINCIPLES 53 switches required for the control and operation of the lighting and power feeders. There is a total of ten triple-pole switches for light- ing, and eighteen for power. An indicating voltmeter and ampere meter are also placed in the switchboard. A voltmeter is provided with a double-throw switch, and so arranged as to measure the poten- tial across the two outside conductors, or between the neutral con- ductor and either of the outside conductors. The ampere meter is arranged with two shunts, one being placed in each outside leg; the shunts are connected with a double-pole, double-throw switch, so that the ampere meter can be connected to either shunt and thus measure the current supplied on each side of the system. Character of Load. The building is occupied partly as a news- paper office, and there are several large presses in addition to the usual linotype machines, trimmers, shavers, cutters, saws, etc. There are also electrically-driven exhaust fans, house pumps, air-compressors, etc. The upper portion of the building is almost entirely devoted to offices rented to outside parties. The total number of motors supplied was 55; and the total number of outlets, 1,100, supplying 2,400 incandescent lamps and 4 arc lamps. Feeders and Mains. The arrangement of the various feeders and mains, the cut-out centers, mains, etc., which they supply, are shown diagrammatically in Fig. 34, which also gives in schedule the sizes of feeders, mains, and motor circuits, and the data relating to the cut-out panels. Although the current supply was to be taken from an outside source, yet, inasmuch as there was a probability of a plant being in- stalled in the building itself at some future time, the three-wire system of feeders and mains was designed, with a neutral conductor equal to the combined capacity of the two outside conductors, so that 120-volt two-wire generators could be utilized without any change in the feeders. Basement. The plan of the basement, Fig. 35, shows the branch circuit wiring for the outlets in the basement, and the location of the main switchboard. It also shows the trunk cables for the inter- connection system serving to provide the necessary wires for telephones, tickers, messenger calls, etc., in all the rooms throughout the building, as will be described later. To avoid confusion, the feeders were not shown on the basement 265 ONDUCTORS IN ONE X* SEPARATE CONDUIT FOR E AGH CONDUCTOR II THIS FEEDER IS TO BE DIVIDED INTO FOUR (-4) ; CONDUCTORS OF * 2000000 CM. - EACH CONDUCTOR 13 TO BE INSTALLED IN A SEP- 3" (INSIDE OIAM} CONDUIT SEPARATE 3" (INSIDE OIAM)CONDUIT FOR EACH CONDUCTOR Fig. 34. Wiring of an Office Building. Diagram Showing Arrangement of Feeders and Mains Cut-Out Centers, etc. 966 ELECTRICAL PRINCIPLES 55 SCHEDULE OF CIRCUITS NO. 2 RISES TO 2"d FUOOR Key Showintf Explanation f Various Symbols used in to 46 Inclusive CeiKntf Oandelier Wall Bracket -Gooseneck BracXet Wall Socket o Drop Cord a ^rc Lamp > -Cooper-Hewitt Lamp - -Cluster Floor Outlet --- Oesk Lltfnt Extension Outlet A Push Button Switch A Snap Switch -Junction Box O Electric Clock Q Master Clock EH Motor Starter - CutOut Ftanel Box Power Pbnal full Box Circuit unier Floor above ---- * Fig. 35. Wiring an Office Building. Basement Plan Showing Branch Circuit Wiring for Out- leta in Basement, Location of Main Switchboard, and Trunk Cables of the Intercon- naction System Providing Wires for Telephone, Ticker, and Messenger Call Service, etc. 267 56 THE MOTION PICTURE plan, but were described in detail in the specification, and installed in accordance with directions issued at the time of installation. The electric current supply enters the building at the front, and a service switch and cut-out are placed on the front wall. From this point, a two- wire feeder for power and a three-wire feeder for lighting, are run to the main switchboard located near the center of the basement. Owing to the size of the conduits required for these supply feeders, as well as the main feeders extending to the upper floors of the building, the said conduits are run exposed on substantial hangers suspended from the basement to the ceiling. First Floor. The rear portion of the building from the basement through the first floor, and including the mezzanine floor, between the first and second floors, at the rear portion of the building only, is utilized as a press room for several large and heavy modern newspaper presses. The motors and controllers for these presses are located on the first floor. A separate feeder for each of these press motors is run directly from the main switchboard to the motor controller in each case. Empty conduits were provided, ex- tending from the controllers to the motor in each case, intended for the various control wires installed by the contractor for the press equipments. One-half of the front portion of the first floor is utilized as a news- paper office; the remaining half, as a bank. Second Floor. The rear portion of the second floor is occupied as a composing and linotype room, and is illuminated chiefly by means of drop-cords from outlets located over the linotype machines and over the compositors' cases. Separate f-horse-power motors are provided for each linotype machine, the circuits for the same being run underneath the floor. Upper Floors. The upper floors are similar in all respects with the exception of certain changes in partitions, which are not material for the purpose of illustration or for practical example. The circuit work is sufficiently intelligible from the plan to require no further explanation. Interconnection System. In the interconnection system, the main interconnection box is located in the basement; adjoining this main box is located the terminal box of the local telephone company. A separate system of feeders is provided for the ticker system, as these ELECTRICAL PRINCIPLES 57 conductors require somewhat heavier installation, and it was thought inadvisable to place them in the same conduits with the telephone wires, owing to the higher potential of ticker circuits. A separate interconnection cable runs to each floor, for telephone and messenger call purposes; and a central box is placed near the rising point at each floor, from which run subsidiary cables to several points symmetrically located on the various floors. From these subsidiary boxes, wires can be run to the various offices requiring telephone or other service. Small pipes are provided to serve as race- ways from office to office, so as to avoid cutting partitions. In this way, wires can be quickly provided for any office in the building without damaging the building in any way whatever; and, as provision is made for a special wooden moulding near the ceiling to accommodate these wires, they can be run around the room without disfiguring the walls. All the main cables and subsidiary wires are con- nected with special interconnection blocks numbered serially; and a schedule is provided in the main interconnection box in the base- ment, which enables any wire originating thereat, to be readily and conveniently traced though the building. All the main cables and subsidiary cables are run in iron conduits. OUTLET-BOXES, CUT-OUT PANELS, AND OTHER ACCESSORIES Outlet Boxes. Before the introduction of iron conduits, outlet- Fig. 36. Universal and Knock Out Type of Outlet Box Fig. 37. Water-Tight Outlet Box boxes were considered unnecessary, and with a few exceptions were not used, the conduits being brought to the outlet and cut off after the 58 THE MOTION PICTURE walls and ceilings were plastered. With the introduction of iron con- duits, however, the necessity for outlet-boxes was realized; and the Rules of the Fire Underwriters were modified so as to require their use. The Rules of the National Electric Code now require outlet-boxes to be used with rigid iron and flexible steel conduits, and with armored cables. A portion of the rule requiring their use is as follows: All interior conduits and armored cables must be equipped at every outlet with an approved outlet-box or plate. Outlet-plates must not be used where it is practicable to install outlet- boxes. In buildings already constructed, where the conditions are such that neither outlet-box nor plate can be installed, these appliances may be omitted by special permission of the inspection department having jurisdiction, pro- viding the conduit ends are bushed and secured. Types of Floor Outlet Boxes Fig. 39. Fig. 36 shows a typical form of outlet-box for bracket or ceiling outlets of the universal type. When it is desired to make an opening for the conduits, a blow from a hammer will remove any of the weak- ened portion of the wall of the outlet-box, as may be required. This form of outlet-box is frequently referred to as the knock-out type. Other forms of outlet-boxes are made with the openings cast in the box at the required points, this class being usually stronger and better made than the universal type. The advantages of the universal type of outlet-box are that one form of box will serve for any ordinary conditions, the openings being made according to the number of conduits and the directions in which they enter the box. Fig. 37 shows a waterproof form of outlet-box used out of doors, or in other places where the conditions require the use of a water- tight and waterproof outlet-box. It will be seen in this case, that the box is threaded for the con- 270 ELECTRICAL PRINCIPLES 59 duits, and that the cover is screwed on tightly and a flange provided for a rubber gasket. Figs. 38 and 39 show water-tight floor boxes which are for outlets located in the floor. While the rules do not require that the floor outlet Fig. 40. Conduit Bushing box shall be water-tight, it is strongly recommended that a water- tight outlet be used in all cases for floor connections. In this case also, the conduit opening is threaded, as well as the stem cover through which the extension is made in the conduit to the desk or table. When the floor outlet connection is not required, the stem cover may be removed and a flat blank cover be used to replace the same. There is hardly any limit to the number and variety of makes of outlet-boxes on the market, adapted for ordinary and for special conditions; but the types here illustrated are characteristic and typ- ical forms. Bushings. The Rides of the National Electric Code require that conduits entering junction-boxes, outlet-boxes, or cut-out cabinets Fig. 41. Lock-Nut Fig. 42. Panel-Box Terminal Bushing shall be provided with approved bushings, fitted to protect the wire from abrasion. Fig. 40 shows a typical form of conduit bushing. This bushing is screwed on the end of the conduit after the latter has been intro- duced into the outlet-box, cut-out cabinet, etc., thereby forming an 271 60 THE MOTION PICTURE insulated orifice to protect the wire at the point where it leaves the conduits, and to prevent abrasion, grounds, short circuits, etc. A lock-nut, Fig. 41, is screwed on the threaded end of the conduit before the conduit is placed in the outlet-box or cut-out cabinet, and this lock-nut and bushing clamp the conduit securely in position. Fig. 42 shows a terminal Fig. 43 Copper-Tipped Fuse Link busning for pan el-boxeS USed for flexible steel conduit or armored cable. The Rules of the National Electric Code require that the metal of conduits shall be permanently and effectually grounded, so as to insure a positive connection for grounds or leaking currents, and in order to provide a path of least resistance to prevent the current from finding a path through any source which might cause a fire. At outlet-boxes, the conduits and gas pipes must be fastened in such a HP. Fig. 44. Edison Fuse-Plug Fig. 45. Porcelain Cut-Out Block manner as to insure good electrical connection; and at centers of dis- tribution, the conduits should be joined by suitable bond wires, pref- erably of copper, the said bond wires being connected to the metal Fig. 46. Enclosed or "Cartridge" Fuse structure of the building, or, in case of a building not having an iron or steel structure, being grounded in a permanent manner to water or gas-piping. Fuse=Boxes, Cut=0ut Panels, etc. From the very outset, the necessity was apparent of having a protective device in circuit with the conductor to protect it from overload, short circuits, etc. For this purpose, a fusible metal having a low melting point was em- 272 ELECTRICAL PRINCIPLES 61 ployed. The form of this fuse has varied greatly. Fig. 43 shows a characteristic form of what is known as the link fuse with copper terminals, on which is stamped the capacity of the fuse. > Fig. 47. Section of Enclosed Fuse The form of fuse used probably to a greater extent than any other, although it is now being superseded by other more modern forms, is that known as the Edison fuse-plug, shown in Fig. 44. A porcelain cut-out block used with the Edison fuse is shown in Fig. 45. Within the last four or five years, a new form of fuse, known as the enclosed fuse, has been introduced and used to a considerable Fig. 48. Porcelain Cut-Outs in Wooden Box extent. A fuse of this type is shown in Fig. 46. Fig. 47 gives a sec- tional view of this fuse, showing the porous filling surrounding the fuse-strips, and also the device for indicating when the fuse has blown. This form of fuse is made with various kinds of terminals; it can be used with spring clips in small sizes, and with a post screw contact in larger sizes. For ordinary low potentials this fuse is de- sirable for currents up to 25 amperes; but it is a debatable question 273 62 THE MOTION PICTURE TABLE VI Carrying Capacity of Wires B. & S. GADOE CIRCULAR MILS RUBBER INSULATION OTHER INSULATION AMPERES AMPERES 18 1,624 3 5 16 2,583 6 8 14 4,107 12 16 12 6,530 17 23 10 10,380 24 32 8 16,510 33 46 6 26,250 46 65 5 33,100 54 77 4 41,740 65 92 3 52,630 76 110 2 66,370 90 131 1 83,690 107 156 105,500 127 185 00 133,100 150 220 000 167,800 177 262 0000 211,600 210 312 200,000 200 300 300,000 270 400 400,000 330 500 500,000 390 590 600,000 450 680 700,000 500 760 800,000 550 840 900,000 600 920 1,000,000 650 1,000 1,100,000 690 1,080 1,200,000 730 1,150 1,300,000 770 1,220 1,400,000 810 1,290 1,500,000 850 1,360 1,600,000 890 1,430 1,700,000 930 1,490 1,800,000 970 1,550 1,900,000 1,010 1,610 2,000,000 1,050 1,670 whether it is desirable to use an enclosed fuse for heavier currents. Fig. 48 shows a cut-out box with Edison plug fuse-blocks used with knob and tube wiring. It will be seen that there is no connection 274 ELECTRICAL PRINCIPLES 63 compartment in this fuse-box, as the circuits enter directly opposite the terminals with which they connect. Table VI shows the allowable carrying capacity of copper wires and cables of ninety-eight per cent conductivity, according to the standard adopted by the American Institute of Electrical Engineers and must be followed in placing interior conductors. For insulated aluminum wire the safe-carrying capacity is 84 per cent of that given for copper wire with the same kind of insulation. The lower limit is specified for rubber-covered wires to pre- vent gradual deterioration of the high insulations by the heat of the wires, but not from fear of igniting the insulation. The question of drop is not taken into consideration in the above tables. The carrying capacity of Nos. 16 and 18, B. & S. gauge wire is given, but no smaller than No. 14 is to be used, except as allowed under rules for fixture wiring. ARC LAMPS Electric Arc. Suppose two carbon rods are connected in an electric circuit, and the circuit closed by touching the tips of these rods together; on separating the car- bons again the circuit will not be broken, provided the space between the carbons be not too great but will be maintained through the arc formed at these points. This phenomenon, which is the basis of the arc light, was first observed on a large scale by Sir Humphrey Davy, who used a bat- tery of 2,000 cells and produced an arc between charcoal points 4 inches apart. As the incandescence of the car- bons across which an arc is maintained, F >B- 49 - * Electric Arc Between Carbon Terminals together with the arc itself, forms the source of light for a large portion of arc lamps, it will be well to study the nature of the arc. Fig. 49 shows the general appearance of an arc between two carbon electrodes when maintained by direct current. Here the current is assumed as passing from the top carbon to 275 64 THE MOTION PICTURE the bottom one as indicated by the arrow and signs. We find, in the direct-current arc, that the most of the light issues from the tip of the positive carbon, or electrode, and this portion is known as the crater of the arc. This crater has a temperature of from 3,000 to 3,500 C., the temperature at which the carbon vaporizes, and gives fully 80 to 85 per cent of the light furnished by the arc. The negative carbon becomes pointed at the same time that the positive one is hollowed out to form the crater, and it is also incandescent but not to as great a degree as the positive carbon. Between the electrodes there is a band of violet light, the arc proper, and this is surrounded by a lu- Fig. 50. Distribution Curve for D. C. Arc Lamp (Vertical Plane) minous zone of a golden yellow color. The arc proper does not fur- nish more than 5 per cent of the light emitted when pure carbon electrodes are used. The carbons are worn away or consumed by the passage of the current, the positive carbon being consumed about twice as rapidly as the negative. The light distribution curve of a direct-current arc, taken in a vertical plane, is shown in Fig. 50. Here it is seen that the maxi- mum amount of light is given off at an angle of about 50 from the vertical, the negative carbon shutting off the rays of light that are thrown directly downward from the crater. If alternating current is used, the upper carbon becomes positive and negative alternately, and there is no chance for a crater to be 276 ELECTRICAL PRINCIPLES 65 formed, both carbons giving off the same amount of light and being consumed at about the same rate. The light distribution curve of an alteiyiating-curreiit arc is shown in Fig. 51. Arc=Lamp Mechanisms. In a practical lamp we must have not only a pair of carbons for producing the arc, but also means for sup- 90* Fig. 51. Distribution Curve for A. C. Arc Lamp (Vertical Plane) porting these carbons, together with suitable arrangements for leading the current to them and for maintaining them at the proper distance apart. The carbons are kept separated the proper distance by the operating mechanisms which must perform the following functions: 1. The carbons must be in contact, or be brought into contact, to start the arc when the current first flows. 2. They must be separated at the right distance to form a proper arc immediately afterward. 3. The carbons must be fed to the arc as they are consumed. 4. The circuit should be open or closed when the carbons are entirely consumed, depending on the method of power distribution. The feeding of the carbons may be done by hand, as is the case in some stereopticons using an arc, but for ordinary illumination the 277 66 THE MOTION PICTURE striking and maintaining of the arc must be automatic. It is made so in all cases by means of solenoids acting against the force of gravity or against springs. There is an endless number of such mechanisms, but a few only will be described here. They may be roughly di- vided into three classes: shunt mechanisms, series mechanisms, differential mechanisms. Shunt Mechanisms. In shunt lamps, the carbons are held apart before the current is turned on, and the circuit is closed through a solenoid connected in across the gap so formed. All of the current must pass through this coil at first, and the plunger of the solenoid is arranged to draw the carbons together, thus starting the arc. The pull of the solenoid and that of the springs are ad- justed to maintain the arc at its proper length. Such lamps have the disad- vantage of a high resistance at the start 450 ohms or more and are difficult to start on series circuits, due to the high voltage required. They tend to maintain a constant voltage at the arc, but do not aid the dynamo in its regulation, so that the arcs are liable to be a little unsteady. Series Mechanisms. With the series-lamp mechanism the carbons are together when the lamp is first started and the current, flowing in the series coil, separates the electrodes, striking the arc. When the arc is too long, the resistance is increased and the current lowered, so that the pull of the solenoid is weakened and the carbons feed together. This type of lamp can be used only on constant-potential systems. Fig. 52 shows a diagram of the connection of such a lamp. This diagram is illustrative of the connection of one of the lamps manu- factured by the Western Electric Company, for use on a direct-current, Fig. 52. Series Mechanism for D. C. Arc Lamp 278 ELECTRICAL PRINCIPLES 67 constant-potential system. The symbols -f and refer to the termi- nals of the lamp, and the lamp must be so connected that the current flows from the top carbon to the bottom one. R is a series resistance, adjustable for different voltages by means of the shunt G. F and D are the controlling solenoids connected in series with the arc. B and C are the positive and negative carbons re- _ spectively, while A is the switch for turning the current on and off. H is the plunger of the solenoids and / the carbon clutch, this being what is known as a carbon-feed lamp. The carbons are together when A is first closed, the current is excessive, and the plunger is drawn up into the solenoids, lift- ing the carbon B until the resistance of the arc lowers the current to such a value that the pull of the solenoids just counter-balances the weight of the plunger and carbon. G must be so adjusted that this point is reached Fig. 53. Differential Mechan- , , . , , ., ism for D. C. Arc Lamp when the arc is at its normal length. Differential Mechanisms. In the differential lamp, the series and shunt mechanisms are combined, the carbons being together at the start, and the series coil arranged so as to separate them while the shunt coil is connected across the arc, as before, to prevent the car- bons from being drawn too far apart. This lamp operates only over a low-current range, but it tends to aid the generator in its regulation. Fig 53 shows a lamp having a differential control, this also being the diagram of a Western Electric Company arc lamp for a direct- current, constant-potential system. Here S represents the shunt coil and M the series coil, the armature of the two magnets A and A' being attached to a bell-crank, pivoted at B, and attached to the carbon clutch C. The pull of coil S tends to lower the carbon while that of M raises the carbon, and the two are so adjusted that equilibrium is reached when the arc is of proper length. All of the lamps are fitted with an air dashpot, or some damping device, to prevent too rapid movements of the working parts. The methods of supporting the carbons and feeding them to the arc may be divided into two classes: rod -feed mechanism, carbon-feed mechanism. 279 THE MOTION PICTURE Rod-Feed Mechanism. Lamps using a rod-feed have the upper carbons supported by a conducting rod, and the regulating mechan- ism acts on this rod, the current being fed to the rod by means of sliding contact. Fig. 54 shows the arrangement of this type of feed. The rod is shown at R, the sliding contact at B, and the carbon is attached to the rod at C. These lamps have the ad- vantage that carbons, which do not have a uniform cross-section or smooth exterior, may be used, but they possess the disadvantage of being very long in order to ac- commodate the rod. The rod must also be kept clean so as to make a good contact with the brush. Carbon-Feed Mechanism. In carbon-feed lamps the controlling mechanism acts on the carbons directly through some form of clutch which grips the carbon when it is lifted, but allows the car- bon to slip through it when the tension is released. For this type of feed the carbon must be Fig. 54. Rod-Feed Mechanism straight and have a uniform cross- section as well as a smooth exterior. The current may be led to the carbon by means of a flexible lead and a short carbon holder. MOVING=PICTURE MACHINES Arc Lamp. Arc lamp used as a part of moving picture machines must be constructed similar to arc lamps of theaters, and wiring of same must not be of less capacity than No. 6 B. & S. gauge. Arc lamps used for stage effects must conform to the following requirements: a. Must be constructed entirely of metal except where the use of approved insulating material is necessary. b. Must be substantially constructed, and so designed as to ELECTRICAL PRINCIPLES 69 provide for proper ventilation, and to prevent sparks being emitted from lamps when same is in operation, and mica must be used for frame insulation. c. Front opening must be provided with a self-closing hinged door frame in which wire gauze or giass must be inserted, excepting lens lamps, where the front may be stationary, and a solid door be provided on back or side. d. Must be provided with a one-sixteenth-inch iron or steel guard having a mesh not larger than 1 inch, and be substantially placed over top and upper half of sides and back of lamp frame; this guard to be substantially riveted to frame of lamp, and to be placed at a distance of at least 2 inches from the lamp frame. e. Switch on standard must be so constructed that accidental contact with any live portion of same will be impossible. /. All stranded connections in lamp and at switch and rheo- stat must be provided with approved lugs. g. Rheostat, if mounted on standard, must be raised to a height of at least 3 inches above floor line, and in addition to being properly enclosed must be surrounded with a substantially attached metal guard having a mesh not larger than 1 square inch, which guard is to be kept at least 1 inch from outside frame of rheostat. h. A competent operator must be in charge of each arc lamp, except that one operator may have charge of two lamps when they are not more than 10 feet apart, and are so located that he can prop- erly watch and care for both lamps. Miscellaneous. Rheostats must conform to rheostat require- ments for theater arcs. Top reel must be encased in a steel box with a hole at the bottom only large enough for film to pass through, and cover so arranged that this hole can be instantly closed. No solder to be used in the con- struction of this box. A steel box must be used, for receiving the film after being shown, with a hole in the top only large enough for the film to pass through freely, with a cover so arranged that this hole can be instantly closed. An opening may be placed at the side of the box to take the film out, with a door hung at the top, so arranged that it cannot be en- tirely opened, and provided with spring catch to lock it closed. No solder to be used in the construction of this box. 281 70 THE MOTION PICTURE The handle or crank used in operating the machine must be secured to the spindle or shaft, so that there will be no liability of its coining off and allowing the film to stop in front of lamp. A shutter must be placed in front of the condenser, arranged so as to be readily closed. Extra films must be kept in metal box with tight-fitting cover. Machines must be operated by hand (motor driven will not be permitted). Picture machine must be placed in an enclosure or house made of suitable fireproof material, be thoroughly ventilated and large enough for operator to walk freely on either side of or back of ma- chine. All openings into this booth must be arranged so as to be entirely closed by doors or shutters constructed of the same or equally good fire-resisting material as the booth itself. Doors or covers must be arranged so as to be held normally closed by spring hinges or equivalent devices. *MERCURY=ARC RECTIFIERS FOR MOTION PICTURES One of the most important factors contributing to the success of a motion-picture theater is the quality and brilliancy of the light projected from the lamps. For pleasing effect motion pictures re- quire a steady, white light of sufficient intensity to bring out the natural light and color values of the films, and the theater having the best quality of light stands the best show of getting the biggest patronage. It is well known that the light obtained from the direct- current is much superior to that from the alternating-current arc lamps. However, until recently all those who could obtain only alternating-current supply have got along with the poorer quality of light simply for the lack of apparatus for economically converting alternating current into direct current. In Fig. 55 is shown a mercury-arc rectifier developed by the General Electric Company for furnishing current of the desired char- acter at a cost less than that of the most economically operated alternating-current arc lamp. There are certain facts which should be borne in mind while making an analysis of the cost of producing a given intensity of pro- jected light from alternating current, direct current, and rectified *By courtesy of the McGraw Publishing Company. 282 ^1 a w ; .2 .a ELECTRICAL PRINCIPLES 71 current with the most approved devices applicable in each case. For instance, the best class of motion pictures requires a light in- tensity of upward of 8,000 candle power, and as 5,000 candle power is the maximum obtainable from alternating current with the best auto-transformers, or the highest current values practicable, it is evident that the use of alternating current under such conditions is Fig. 55. Front and Back Views of Mercury-Arc Rectifier for Moving-Picture Machine entirely satisfactory owing to the insufficiency of the light. Where direct-current supply is obtainable, some have found relief by using it, but their experience has served to emphasize the prohibitory effect of the additional cost entailed by the loss of at least 60 per cent of the energy drawn from the line in the resistance or rheostat employed to regulate the current in the arc. These facts serve to define the limitations of both the alternating- 285 72 THE MOTION PICTURE current and the direct-current arc relative to motion-picture light- ing, but in order to give the various alternating-current methods a fair basis for comparison, assume that a light intensity of 5,000 candle power is required. From actual determinations carefully made it is found that to obtain 5,000 candle power from a 110- volt alternating-current circuit with rheostats requires 7 kilowatts; a 110-volt direct-current circuit with rheostat requires 2.25 kilowatts; any alternating-current circuit with auto-transformer requires 2.1 kilowatts, and with mercury-arc rectifier requires 1.7 kilowatts. Since auto-transformers are extensively used in alternating- current supply systems to obtain a substantial reduction in energy consumption, the method of using alternating current with rheostats may be considered as obsolete, and since a prohibitory amount of energy is wasted in using direct current with a rheostat, that method can be omitted from present consideration. This affords a direct comparison between the alternating current with the use of econo- mizers on the one hand and mercury-arc rectifiers on the other. The figures given above show a difference of 400 watts in favor of the mercury-arc rectifier. This means than on the basis of an average daily run of seven hours at a cost of 6 cents a kilowatt-hour the use of a mercury-arc rectifier provides a light having all the advantages of that given by a direct-current arc at a cost of at least $60 per year less than that obtained from alternating current with the best type of auto-transformer. Furthermore, it is evident that when the light intensity required exceeds 5,000 candle power, thus rendering the alternating-current method inapplicable, the saving effected by the use of the mercury- arc rectifier as compared to the cost of using direct current with a rheostat is much more significant. For instance, to obtain 7,500 candle power requires 3.1 kilowatts from direct current with rheostat and 2.15 kilowatts from alternating current with mercury-arc rec- tifier. The difference in favor of the mercury-arc rectifier is 950 watts, which means a saving of at least $145 per year. In addition to the positive money-saving capability of the device, the excellent light of practically any candle-power obtainable from alternating-current supply and the reliability, ease, and safety of operation render the mercury-arc rectifier particularly desirable for making pleasing and successful "photo plays." 286 REVIEW QUESTIONS 287 REVIEW QUESTIONS ON THE! STJBJHJOT OV PHOTOGRAPHY 1. What are the three very general divisions or steps in mak- ing photographs? 2. How would you focus a camera upon a subject to be pho- tographed? 3. What is meant by the focal length of a lens? 4. How would you measure or estimate the focal length of a lens? 5. Name more than one kind of aberration in a photographic lens which may be "corrected" by proper lens construction. 6. Name more than one kind of camera shutter. 7. What is a photographic darkroom? 8. What is the routine of camera manipulation to make a photographic exposure on the glass sensitive plate? 9. Seven points were given in the text for care in arranging the image upon the ground glass. Name at least four of them. 10. The image having been arranged upon the ground glass, how is it recorded to form a negative? 11. What means are available for estimating the length of an exposure, after the camera is ready? 12. How does changing the size of the diaphragm opening affect the exposure? 13. What is meant by development? 14. Name more than one method of development. 15. Describe one method of development, including fixing and washing the negative. 16. What is meant by red lamp, ruby lamp, or safe light? 17. What is meant by printing? 18. Describe one process of printing. PHOTOGRAPHY 19. What differences can you mention between a lantern slide and an ordinary photograph? 20. What is a stereograph? 21. Define telephotography. 22. Explain the use of autochrome plates. 290 REVIE.W QUESTIONS ON THE SUBJECT OB- MO T O a R A P H Y 1. Name some of the classes of motion-picture subjects as classified by the nature of the subject. 2. What divisions of labor are made in the producing of commercial motion pictures for amusement purposes? 3. What is the nature of a motion-picture drama? 4. What is the requirement of a motion-picture comedy? 5. W r hat is a scrip? Describe how it is written. 6. What are the duties of a producer? 7. What is the order of work in producing a drama? 8. How are indoor studios lighted? 9. What are the property man's duties? 10. What is a "lecture" and how is it written? 11. What are the necessary divisions of the photographic factory for motion pictures? 12. How is raw strip film made before its purchase by the motion-picture factory? 13. What are the proper dimensions for film strip, pictures, and sprocket holes? 14. Name several of the features which a good motion-picture camera should have. 15. How is a camera man able to regulate the photographic exposure value of the light upon the film? 16. How is a 200-foot motion-picture film developed and printed? 17. When and how are title negatives made for a motion picture? 18. Describe one process of making a title. 291 MOTOGRAPHY 19. Name the two kinds of printing machines. Describe one of them briefly. 20. Describe the processes of staining a film, and of toning, or monochroming, a film. 21. Describe the different processes of coloring films. REVIEW QUESTIONS ON THE SUBJECT OK MOTION-PICTURE THEATER 1. In studying a theater, what points should a manager notice? 2. In studying a theater with a view to purchase, what points should be studied? 3. Name a few of the "side lines" possible in managing a motion-picture theater to add to the ticket-window income. 4. When should "side lines" be avoided in managing a theater? 5. What are the steps to be taken in starting a new theater? 6. In studying the location of a new theater among existing competing theaters, how is the probable income of the proposed theater estimated? 7. In studying a theater location in unoccupied city territory, how is the probable income of the proposed theater estimated. 8. In a small town, how is the probable income of a small theater estimated? 9. How would you try to raise the money to start a theater? 10. What is meant by the "program" of a motion-picture theater? 11. WTiat is a sloping floor and what are its advantages? 12. In what two ways may a sloping floor be put in? 13. Describe a good cheap picture screen. 14. Describe the mirror screen. 15. Describe an airdoim. 16. What means has the theater manager for advertising his theater? 17. What is a feature film? 18. How may a feature film be advertised? MOTION-PICTURE THEATRE 19. Describe a "special program," either describing one of the kinds mentioned in the textbook, or devise a new special pro- gram yourself and describe it. 20. How would you proceed, as manager, to get a good con- tract with a film exchange? 21. What precautions against the film exchange must be taken in renting film which is furnished under an age limit? 22. Describe in detail one "Side Line for Profit." 294 REVIEW QUESTIONS ON THE) SUBJECT OF ELECTRICAL PRINCIPLES 1. What is an electrical charge in motion called? 2. Describe the simplest form of a galvanic cell. 3. On what principles are electrical currents, in general, measured? 4. What does e. m. f. mean? 5. State Ohm's Law. 6. Describe the action of a simple primary cell. 7. What is polarization in relation to primary cells? 8. Discuss the magnetic properties of a helix. 9. What is an electromagnet? 10. Make a diagram of the connections of a simple bell. 11. The resistance of a certain wire is 7.92 ohms, what is its inductance? 12. The resistance of a wire 629 feet long is .27 ohms. What is the resistance of the same wire 3,215 feet long? 13. How is the resistance of a conductor influenced by its cross-section? 14. Define specific resistance. 15. State the general formula for resistance calculation. 16. How is electrical conductance in metal conductors affected by temperature? 17. State the area of No. 10 B. & S. wire in circular mils and its resistance in ohms per 1,000 feet. 18. If the resistance of a certain wire is 2.3 ohms per 1,000 feet, how many feet of the wire will be required to make up a resist- ance of 17.8 ohms? 19. The resistance of a circuit is 1.8 ohms and the voltage is 110. What is the current? 295 ELECTRICAL PRINCIPLES 20. Eight cells each having an e. m. f. of 9 volts and an internal resistance of 6 ohms are connected in parallel, and the external resistance of the circuit is 3.4 ohms. Find the current. 21. Which system of wiring is recommended in fireproof buildings? 22. What determines, usually, the system of wiring? 23. What is considered in locating the outlets for conductors in a building? 24. Make a sketch of an enclosed fuse. 25. How many amperes would No. 10 B. & S. rubber insu- lated wire safely carry? ' 26. What number of wire would you select for transmitting 30 amperes? 27. Sketch the series mechanism for d. c. arc lamps. 28. Describe and sketch the differential mechanism for d. c. arc lamps. 29. What B. & S. gauge number must be used for arc lamps in connection with moving pictures? 30. How many amperes will this conductor safely carry? INDEX 297 INDEX The page numbers of this volume will be found at the bottom of the pages; the numbers at the top refer only to the section. A Page Aberration 20 Actors 105 starring an actor 106 stock companies 105 Advertising 197 Advertising drop curtain 207 Advertising slides 207 Airdome 195 Announcement slides 199 Arc-lamp mechanism 277 differential mechanism 279 rod-feed mechanism 280 series mechanisms 278 Arc lamps 275 electric arc 275 mechanisms 277 Astigmatism 22 Author 76 his problems 77 art, limitations of 77 plot 77 scenario 78 who is 95 Autochrome plates 65 Automatic music 203 B Bianchi camera 140 Bichromatic cell 226 Blue prints 55 Bushings 271 C Camera 11, 122 buying 13 construction of 14 exposed and unexposed films 126 Note. For page numbers tet foot of pages. 2 INDEX Camera Page film movement 123 loading 127 loading film holders 125 Camera man 122 Camera man's duties 128 control of image 133 duplicate exposures 138 exposure control 134 exposure meters 136 exposure time 134 finders 139 focusing 132 indicator 139 lens length 131 marker 139 reversing : 139 setting up camera 131 shutter 133 taking picture 128 trick crank 138 turning crank . . . 129 Camera operation, routine of 27 Candy kid 208 Cells, combination of 230 Chase and trick scrip, specimen 83 Chases 72 Chromatic aberration 20 Chronophotography 69, 155 motographic microscopy 156 motographic untramiscroscopy 156 X-ray motography 156 Colored photographs 64 Coloring films 151 hand process 151 machine process 152 stencil process 151 Comedy 72 specimen 82 Competition 171 Conductivity '. . 238 Country theater 192 Current events 72 Current flows, laws of 236 D Daniell cell 227 Darkroom 27 Note. For page numbers sec foot of -pages. 300 INDEX 3= Page Developing formulas 48 acid hypo fixing bath 49 hydro-metol developer 48 intensification 50 pinholes 51 plain hypo fixing bath 48 pyro developer 48 reduction 50 removing pyro stains 49 retouching and spot ting 50 Developing papers 56 Developing prints 148 Development 43 developers 43 factorial 46 fixing 47 fixing after washing 47 negative image 43 ruby lamp 44 sight 44 tank 46 trays and covers 44 washing before fixing 47 without red lamp 47 Drama scrip, specimen 78 Dramas 72 Drawn pictures 73 Dry cell .' 229 Dry plates 35 Dull season... 205 Electric arc 275 Electric bell 235 Electric signs 198 Electrical currents, measurement of 218 Electrical principles ... .213-284 arc lamps 275 electricity in motion 213 electromagnetism laws of current flow . 236 mercury-arc rectifiers moving-picture machines primary cells wiring methods 256 Electrical resistance 221 Electricity in motion 213 Note. For page number* see foot of pages. 301 4 INDEX Page Electromagnet 234 Electromagnetism 232 electric bell 235 electromagnet 234 magnetic properties of a helix 233 magnetic properties of a loop 232 rules for north and south poles of a helix 233 Electromotive force of galvanic cells 220 Electromotive force and its measurements 218 Exposure 35 calculation of 40 duplicate 42 exposure meters 41 light intensity 38 nature of subject 38 plate speed 37 stop numbers 36 with single lens ' 42 F Feature films 200 Feeders and mains 263 Film, perforation of 119 perforating machines 121 perforating room 122 shape 120 spacing 120 Film, storage of 119 Film development 141 cages 141 developing 142 drying ' 142 room 142 trays 141 washing m 142 Film industry, branches of 112 Financing a picture theater 175 Fuse-boxes, cut-out panels, etc 272 G Galvanic cell 214 electromotive forces of 220 internal resistance of 222 Galvanic cell and static machine, comparison of 216 H Hamacek camera 140 Note. For page numbers see foot of pages. 302 INDEX 3 Page Handbills 200, 208 Hiring employes 202 Image inverted 12 pin-hole 11 recording 35 Income vs. expense 172 Industrial scrip, specimen 94 Industrials 71 Inverted image 12 K Keeping accounts 203 Kinephotography 70 chases 72 comedies 72 current events 72 dramas 72 industrials 71 travels 71 trick pictures 72 L Lantern slides 61 Leclanch6 cell 229 Lens printing 58 enlargements 59 Lenses 14 astigmatism 22 chromatic aberration 20 diaphragm opening 17 focal length 16 focusing 19 measuring length 17 spherical aberration 20 Location of picture theater ,: . . . 173 among competitors 173 new territory 174 small town 175 M Magnetic effect due to a charge in motion 213 Magnetic field about a current, shape of 217 Making titles 143 Note For page numbers tee foot of pages. 6 INDEX Page Manager, art of 169 Mercury-arc rectifiers for motion pictures 282 Metal-surfaced screen 186 Mirror screen 187 Monochroming 149 Motion-picture theater 165-210 management 165 art of manager 169 competition 171 income vs. expense 172 "sick" motion-picture theater 165 theater for profit 172 traffic 172 operation 195 advertising 197 announcement slides 199 automatic music 203 dull season 205 electric signs 198 feature films 200 handbills 200 hiring employes 202 keeping accounts 203 newspapers 200 noise wagon 200 poster service 198 printed programs 200 program 196 renting films 202 side lines for profit 207 song slides 202 special program 201 studying audiences 195 tickets and chopper 205 vaudeville 203 starting a theater 173 financing 175 selecting location 173 among competitors 173 new territory 174 small town 175 special buildings 188 airdome 195 country theater 1 92 exclusive picture house 189 small vaudeville theater 189 store-front city theater building 176 Note. For page numbers tee foot of pages. 304 INDEX ; Page Motographic microscopy 156 Motographic ultramicroscopy 156 Motography 69-162 , author 77 methods of production 73 division of labor 76 early , 73 drawn pictures 73 photographic process 74 separate cameras 74 multiple camera 74 modern 75 producer 95 product desired 69 reproduction 116 salesman 112 Moving-picture machine 280 arc lamp 280 extra films 282 handle 282 machines 282 rheostats 281 shutter 282 steel box 281 top reel 281 N Newspaper advertising 200 Noise wagon 200 O Ohm's law 222 applications of 248 divided circuits 252 fall of potential in circuit 250 joint resistance of divided circuits 254 series circuits 249 simple applications 248 Operation of a picture theater 195 Orthochromatic photography 64 Outlet boxes 269 Outlets, location of 258 P Packing films for shipment 154 Panoramas 62 Nott.For page nvmberi tee foot of pages. 305 8 INDEX Page Photographer 116 Photographic equipment 155 buying cameras 155 buying films 155 fire' risk in storing films 155 making cameras -. 155 Photographic factory, division of 116 Photographs, colored 64 Photography 11-66 mechanical details 11 orthochromatic 64 printing 51 recording image 35 special application of 61 theory 11 tri-color 65 Picture house, large exclusive 189 Pictures without studios 103 Pin-hole image 11 Plate-holder 26 Polarization 226 bichromatic cell 226 Daniell cell 227 dry cell 229 LeclanchS cell 229 Poster service 198 Primary cells 223 action of a simple cell 223 combination of cells 230 polarization 226 storage battery 231 Print spotting 149 Printed program 200 Printing 51, 144 developing papers. 56 developing prints 148 exposure 146 film adjustment during printing 147 hand staining 150 inspection 148 lens printing 58 machines 144 making exposure ticket 148 print spotting 149 printing frame 52 printing-out papers 52 processes 51 Note. For page numbers see foot of pages. 306 INDEX 9 Printing Page repeater printing 150 room 144 self-toning paper 55 staining 149 toning or monochroming 149 Printing-out papers 52 chloride papers 52 combined toning and fixing 55 final washing 54 fixing 54 stopping 54 toning 53 washing before toning 53 Producer of picture 95 actors 105 pictures without studios 103 producing a drama 107 properties and costumes 105 rehearsals 106 studio lighting 101 studio scenes 96 Producing a drama 107 final criticism Ill motion scenes 108 padding 109 review and criticism 109 rewriting 110 titles 110 Producing image 28 background 29 composition and balance 31 distortions 34 horizon line 32 lighting 30 point of view 32 principal object 29 prominence of background , 32 rising front 35 size of object 30 swing back 34 Program 19 Program advertising 208 Properties and costumes 105 R Raw film 117 coating 118 Note. For page numbert tee foot of pagei. 307 iO INDEX Raw film Page composition 117 manufacture 117 non-inflammable 118 Recording image 35 development 43 dry plates 35 exposure 35 films 35 Rehearsals 106 Rentng films 202 Reproduction 116 camera 122 camera man ' 122 camera man's duties 128 chromophotography ' . 155 coloring films 151 development of films 141 factory floor plan 140 making titles 143 packing films for shipment 154 perforation of film 119 photographer 116 photographic equipment 155 photographic factory 116 printing 144 raw film 117 reclaiming waste 154 storage of film 119 trick pictures 156 waterproofing 154 Resistance 236 affected by heating 242 calculation of 239 inversely proportional to cross-section 237 proportional to length 236 specific resistance 238 Ruby lamp 44 S Salesman 1 12 advance shipment branches of film industry 112 factory schedule 114 lectures 112 release dates 113 sales contracts 115 selling methods 112 Note.^For page numbers see foot of pages. 308 INDEX ll Salesman Page title posters 116 Scenario 78 Self -toning paper 55 blue prints 55 sepia 56 Sepia 56 Sheet music sales 210 Shutters 24 cap 24 curtain 24 focal plane. 25 leaf 24 testing 25 "Sick" motion-picture theater 165 Side lines for profit 207 advertising drop curtain 207 advertising slides 207 candy kid 208 handbills 208 program advertising 2Qf refreshment annex 21C sheet music sales 210 wall posters 207 Sight development 44 Sign flasher 199 Simple cell, theory of action of 224 Slot machines 209 Small-vaudeville theater , 189 Song slides 202 Special buildings 188 airdome 195 country theater 192 large exclusive picture house 189 small vaudeville theater 189 Special programs 201 amateur night 201 contests 201 double price 202 school children 201 Specific resistance 238 Spherical aberration 20 Staining 149 Stereographs 62 Stop picture 161 Storage battery 231 Store-front city theater building 176 elaborate store front 181 Note. For page numbers tee foot of page*. 309 12 INDEX Store-front city theater building Page floor plan 177 lighting methods 179 low-cost store front 179 picture screen 186 sloping floor 184 specimen expense sheet 184 stage 185 weekly expense sheet 183 Studio lighting > 101 artificial 101 daylight 102 glass house type 102 turntable type 103 yard studio type 103 Studio scenes 96 T Tables American wire gauge (B. & S.) '. 244 day and hour exposure chart 39 equivalent stop numbers in focal-factor and uniform systems 37 exposure chart 135 primary cells, electromotive force, resistance, etc 246-247 relative resistance of chemically pure substances at 32 F. interna- tional ohms 240 Stubs' or Birmingham Wire Gauge (B. W. G.) 245 temperature coefficients 243 wires, carrying capacity of 274 Telephotography 63 Theater, starting 173 Tickets and chopper 205 Title posters 116 Toning 149 Traffic 172 Travel and comedyscrip, specimen 92 Travel scrip, specimen 90 Travels 71 Trick notes 87 Trick pictures 72, 156 blackroom 160 dissolving views 159 double exposures 159 double printing 159 dummies . 157 ghosts .- 158 mirrors 160 reversals 157 Note. For page numbers tee foot of pages. 310 INDEX 13 Trick pictures Page speed pictures 157 stop picture 161 Tri-color photography 65 V Vaudeville 203 W Wall posters ; 207 Waterproofing 154 Wiring methods 256 outlet boxes, cut-out panels, etc 269 planning an installation 256 wiring an office building 264 Wiring an office building 264 basement 265 character of load 265 electric current supply 264 feeders and mains 265 first floor 268 interconnection system 268 second floor 268 switchboard 264 upper floors 268 X X-Ray motography 156 Z Zoetrope 73 Note, For page numbers see foot of pages. 311 S. MOSS AGENT 3 -n <-> S is i 3 University of California SOUTHERN REGIONAL LIBRARY FACILITY 305 De Neve Drive - Parking Lot 17 Box 951388 LOS ANGELES, CALIFORNIA 90095-1388 Return this material to the library from which it was borrowed. OCT 6 2003 RECEIVED APR J. 6 2004 ARTS LIBRARY ^ s flE-t!NIVER% -I! SI-LIBRARY^ <^UIB ^ 5 II OF-CAIIFO^ I 1 II < S I 1 UCLA-Theater Arts Library TR 850 H87c v.2 L 006 285 071 4 Bfiu I 'KCC % AA J? 0083535 5 | |7^I% 1 i i s I I 5 & IDS ANGELA > ** r ^ %** ^ rj!30NV-SO^ "^a^AiN,!.]^ \\EUNIVER% ,*IOS ANGEL i 9 S ^/OJIIVJ-JO^ 5 ^^P i^c. ^Aavjiaii-^ y