IS-ANCElfj> *^^^^^v rrt iCi 3AINfl-3\\V -< by $> I I JBRARYQc S I unvj-jo^ CAll HVNHIB^ > i 1 .^clOS-ANCElfX; iS-ANCEl^f. PR f ^ , - s A\\EUNIVER% < S JBRARYQr Jl avaan-^ II ^ i i Sic JC "y, ^**~ OF-CALIF S I I I 8 II I I 1 | i > ^UIBRARYQc ^E-UNIVER% g OF-CAIIFO/^ 1 ^UIBRARY^. THE BARNET BOOK OF ~ PHOTOGRAPHY. THE BARNET BOOK OF ~ PHOTOGRAPHY. A COLLECTION OF PRACTICAL ARTICLES CAPT. W. DE W. ABNEY, C.B.. F.R.S., ETC. CHARLES H. BOTHAMLEY, F.C.S., F.I.C. CHAPMAN JONES, F.C.S., F.I.C, HAROLD BAKER A. HORSLEY HINTON JOHN H. AVERY W. THOMAS ANDREW PRINGLE JOHN A. HODGES, F.R.P.S. REV. F. C. LAMBERT, M A. W. ETHELBERT HENRY, C.E. JAMES PACKHAM, F.R.P.S. THOS. S. SKELTON THIRD EDITION. PUBLISHED BY ELLIOTT & SON, BARNET, HERTS PERCY LUND, HUMPHRIES & Co., LTD., 3, AMEN CORNER, LONDON, E.G. 1898. CONTENTS OF THE BOOK. PAGE. ALPINE PHOTOGRAPHY. W. de IV. Abney, C.B., F.R.S. g NEGATIVE MAKING. C. H. Bothamley, F C.S., F.I.C. 23 LENSES. Clupman Jones, F.C.S., F.I.C. 57 PORTRAITURE. Harold Baker 77 PICTORIAL PHOTOGRAPHY. A. Horsley Hinton - - - 87 ARCHITECTURAL PHOTOGRAPHY. John H. Avery - - 117 THE HAND CAMERA AND ITS USE. W. Thomas - - 131 LANTERN SLIDES. A ndrew Pringle ------ 141 How TO MAKE ENLARGEMENTS. John A. Hodges, F.R.P.S. 155 P.O.P. Rev. F. C. Lambert. M.A. 177 PLATINOTYPE PRINTING. A. Horsley Hinton - - - 197 CONTACT PRINTING ON BROMIDE PAPER. W. Ethelbert Henry, C.E. - - - 225 THE GUM-BICHROMATE PROCESS. Jas. Packham, . F.R.P.S. - - - 241 AN INTRODUCTION TO CARBON PRINTING FOR BEGINNERS 253 THE CARBON PROCESS. Thomas S. Skelton - - - 261 ILLUSTRATIONS. HOMEWARDS. KARL GREGER -------- 16 AMONG THE ALPS. W. DE W. ABNEY 24 WINTER TIME ON THE ALPS. W. DE W. ABNEY - 40 MELTON MEADOWS. A. HORSLEY HINTON - - - 72 Miss LILY HANBURY A PORTRAIT. HAROLD BAKER 88 GATHER THE ROSES WHILE YE MAY. ALEX. KEIGHLEY 120 BIRCH AND BRACKEN. W. THOMAS 136 DRIFTING STORM CLOUDS. W. THOMAS - - - - 168 STREONSALCH. W. J. WARREN -.----- 200 CUPBOARD LOVE. T, LEE SYMS ------ 232 AT THE FOUNTAIN. J. W. WADE ------ 264 936243 THE BARNET BOOK OF PHOTO- GRAPHY. PREFACE. The purpose of this book is to place in the hands of every Photographer in- structive articles on essential processes and manipulations, by eminent writers who have given such subjects their especial study, and who have borne in mind that whilst the experienced Amateur and the Professional may each find much to learn from a comparatively elementary description of methods and means, it is the Beginner who stands in greatest need of help. In the mind of every photographer the name of Barnet is inseparable from a great Photographic Industry, and now it is intended that the name shall be associated with a good and useful book, which is called the BARNET BOOK OF PHOTOGRAPHY, and it is left to the reader to say if the fulfilment of its purpose and the manner of its doing are such as to justify its existence. To all mho are interested in photography, who love it for itself and for its productions, and who desire to improve their own practice of its many processes and applications, this Book is respectfully dedicated. Barnet, Herts. April, 1898. ELLIOTT & SON. COPYRIGHT. A FAMOUS PIKE STREAM. Contact Print on BARNET PLATING-MATT BROMIDE PAPER. Alpine Photography. M KITING in London on a day in winter with a murky sky and sloshy streets, the title of Alpine Photography is verily re- freshing. It brings back days of sunlight and joyous experiment, and as we write the soul stirring scenery is before us called up by photo- graphs taken under varying conditions of comfort and discomfort. That there is something different in Alpine photography to photography in our own country, we are bound to believe, since a special article is demanded for it. The first question in- variably asked is as to the nature of the outfit required. We should here like to divide our reply into two divisions. The one con- cerning the mountaineer, and the other the ordinary tourist. For the former we have no doubt in our minds that a hand camera to take plate or j x 4 pictures is IO BARNET BOOK OF PHOTOGRAPHY. the most convenient form of camera to take. It is not our business to advertise any person's wares and we shall content ourselves by saying that personally we prefer a camera which has separate slides and does not possess a magazine, more particularly when glass plates are to be used, though a form of kodak is not to be despised. But perhaps we are prejudiced in favour of glass plates, for they are simple to manipulate and have no cockles nor other drawbacks which the careless photographer may have to encounter. Probably the most useful lens to employ is a doublet of which the focal length is about a quarter more than the width of the plate, since it includes a fair angle and the margins of the photographs are not likely to be markedly different in general density to the centre, as is the case when wide-angle lenses are employed. In England a lens which will cover with a large stop, say f/8, is a desideratum, but in the Alps it is very rarely that such a large ratio of aperture to focal length is required. As a rule for ordinary plates a lens has to be stopped down to //i6 to give a negative in say /^th of a second. Nevertheless where orthochromatic plates are to be employed it is very necessary to have a lens which will cover a plate satisfactorily with f/8 in order to use a colour screen for producing orthochromatic effects, since the loss of photographic light caused by the screen can only be compensated for by such an aperture even when the shutter is slowed down. The reader is therefore recom- mended on the whole to furnish himself with one of the modern lenses which work at f/8, though he must remember that the larger the aperture employed the more the margins and centre of the picture will suffer from unequal exposure. With some hand cameras there is a means of attachment to a stand, but a stand on a mountain is difficult to use and moreover has on more ALPINE PHOTOGRAPHY. II than one occasion been proved dangerous to carry. The mountaineer if he desires to give a time and not an instantaneous exposure on his excursion, would do well to have a small clip ready to attach to the head of his ice axe. The axe will form a sufficiently stable stand for the more prolonged, but still short, exposure that he may be required to give on some particular subjects such as a photograph at sunrise or near sunset. Photographers in England are rarely afflicted with breathlessness through exertion, but it is different in mountaineering. A mountaineer may keep his wind, but it would be rare to find that his heart was beating equably after some spurt of exertion, such as rock climbing. It is often after some such exertion that he comes upon some view which he may wish to record on his photographic plate. The usual method of holding the hand camera would under such circumstances prove a failure so far as sharpness of image is concerned. Pressed against his " middle " or "upper" chest, the beatings of the heart will record themselves on the photograph. Under such circum- stances resort must be had to some form of support on which to rest his camera. After many years' experience, the writer has come to the conclusion that there is no support superior to the ice axe. It is not necessary to cause it to stand upright in the ground, ice, or snow, though this should be done if possible. It will suffice to rest the point on the rock, and place the camera on the axe head, with the pick parallel to the body. We then have a firm support in one direction, and the hands, which are not affected by the automatic motion of the heart, can be trusted to keep it steady in the other direction. Photographs taken with a good lens, and with such a stand, will bear enlarging up to 22 inches, at least. It is because these photographs will bear 12 BARNET BOOK OF PHOTOGRAPHY. enlarging that a small plate is recommended to the mountaineer. There is not a large proportion of Alpine views taken on the mountain side of which one would care to have anything but a memorandum, and it is such a size as that recommended which gives such a memento, and which, if desired, allows a more formidable size to be acquired at home, where we may suppose there are all the conveniences that a photographic laboratory affords. The writer has had experience on mountains with cameras varying from 12 x 10 to the ^ plate size. When younger and more inclined to waste a few valuable minutes of day-light in putting up a camera stand, the 12 x 10 gave pictures which we often lamented having taken, whilst in his more mature years, a snap-shot has never been regretted. The cameras which require stands, require one porter at least to carry them, for although the late Mr. Donkin carried his own 7^ X 5 camera up the highest peaks, it is few men, who, even if they had the energy or the physique that he had, would imitate his example. A porter means an extra expense in fees, and an extra mouth to feed, and very likely entails slowness in a climb through having an additional man upon the rope. A quarter plate or a 5 x 4 camera the owner, however, can himself carry ; but the best form of attaching it to his body has been a difficult task to evolve. Many and many different attachments have been tried. One thing is quite certain, and that is, the camera should be in a stout case, but it cannot be carried over the shoulders by a strap as we can do in comparatively level countries. Let anyone try to come down a rock with the camera slung over his shoulders, and he will soon find it dangling in front of his stomach, or swinging like a pendulum, and threatening to displace him from what at best may be a treacherous handhold. The method ALPINE PHOTOGRAPHY. of attachment we adopt now, will be readily seen from the diagram. The shoulder strap is utilized, but a ring is attached to the back of the case as shown, and a strap or piece of whipcord comes over the strap as shown. The two shoulders are in AA and the case is carried as a knap- sack. The length of the cord or strap BB is so adjusted, as is also the length of the shoulder strap, that the camera lies against the small of the back, and that it will not swing away from the body. At one time the ring was placed in front of the case, but the result was merely to cause the top of the case to rest against the back. The plan shown above has answered under almost ,every variety of circumstances, and the weight is inconsiderable. (A friend has his camera attached to the bottom of a small "riicksac" and this answers, but as the writer does not carry his own provisions or change of garments he has not adopted this plan). A long day's march may be undertaken if this contrivance be employed, and the weight is scarcely felt. For those who have not had extensive practice with hand cameras, a view finder is, if not a necessity, at all events, a great help. On the whole, perhaps the best form is that in which a miniature view falls on a ground glass. It must be recollected, however, that each view finder is 14 BARNET BOOK OF PHOTOGRAPHY. adapted for some particular focal length of lens. The view in the finder and on the plate should be compared, and if the former is more extensive, the surplus ground glass should be covered up with a black mask. If it be determined to take a camera with its stand, very few directions are required beyond those which apply to ordinary view work on the plains. It may perhaps be as well to mention that a camera stand placed on ice or snow, is not immovable until the iron shoes ot the legs attain the temperature of the surrounding snow or ice. An exposure of a few seconds will often show an image which has moved on the plate. The next point that we may call attention to is the plate to be employed. With a hand camera there is no absolute necessity to have the most rapid plate, as far as exposure is concerned, but in mountain work it must be recollected that there are vary great contrasts to represent on the print. "The slower the plate the steeper the gradation" is almost axiomatic, and it must be recollected that only a certain amount of opacity will print if the deepest shadows only are to be kept of the greatest black obtainable in a print. It is evident that the greater the range of light and shade that is obtained of a printable density, the more true to nature the picture will be. For this reason a quick plate with a moderate gradation is to be preferred as being most generally useful but it should be a plate which is absolutely free from fog, and it should also be of as fine a grain as possible, the size of which has some- thing to do with development. This is still more true when a camera stand and hand exposures are made. With a slow plate with feebler intensities of light, which must be the case when the lens is stopped down to admit of hand exposures, the gradation becomes more steep than if a fairly bright light be employed. A quick plate does not ALPINE PHOTOGRAPHY. 15 suffer in the same way, however small the stop may be. It has already been stated that isochromatic plates may be employed with a hand camera. For ice and snow views there is not much to commend their employment, unless to give a deeper shade to the sky and to the vast crevasses which r.o often form part of the foreground. The darker tky allows faint clouds to be visible in a print when the)' otherwise would be absent. Piclorially thus the isochromatic plate has something to recommend it. Celluloid films nave often been substituted for plates by the writer, and excellent photographs have been obtained on them when they were fairly rapid. There is not much to be said in their favour as regards weight, for in most cameras the support for them weighs nearly as much as the glass plate. There is also a disadvantage in developing them, for they are not so easily manipulated as a rigid body. For convenience in travelling, however, they are to be highly commended. A gross of cut films do not weigh so much as a dozen plates and occupy much less space in the bagga;;e. The question of the use of a Kodak camera with its roller slide, has not been brought forward, not because excellent results cannot be obtained with it, but simply because the writer prefers to use plates and films which can be got at at any time for the purpose of development. For travelling on the continent, and to one's mountain destination, experience has shown that a small hamper is the safest receptacle of all the necessary kit. A hamper which will contain two camera cases side by side is really sufficient ; but it should be a little greater in depth. It may be thought that two cameras are to be taken, but such is not the intention. If a zinc trough be made of the size of one camera case it will contain all the developing apparatus necessary, the lantern, and the plates or films, and all the few etceteras which go to l6 bARNET BOOK OF PHOTOGRAPHY. make one happy. (A screwdriver, a file, and some extra screws, and gummed paper and white blotting paper cut to the sizs of the plates should be enough for the etceteras). The hamper may be arranged so that the camera and view finder may be taken out without any derangement of the rest of the articles in it. The developing bottles and cups, with the dishes, may be similarly extradited. This prevents undue trouble in unpacking and packing. One grand thing to remember is, pack well but not distressingly tightly, in other words don't employ an expert packer if you wish for comfort. Have the hamper a size too large rather than a size too small. Also be it remembered that it is useless to stopper the bottles with all sorts of devices at home, and have to pack in an ordinary manner when once the contents of the hamper have been brought into use. Have your bottles covered with an indiarubber cap which can easily be removed and replaced ; of course we are assuming that development is to take place during one's travels, and not to be left over for home. Personally we think that a speedy development after a view is taken will give the best picture. It may often happen that an undeveloped sensitive plate or film will suffer by its travels. There will or may be scratches and what not, which would be absent if the negative is finished at the time. The outfit for development which need only be taken is as follows : four developing dishes, bottles or cartridges of the dry developer, ammonia diluted to half its strength in a glass stoppered bottle (if in a wooden case, as for medicine bottles, it will be a further protection), a couple of tins of hyposulphite pounded up before the journey, carried in small tins (such tins as the half-plate platinum paper comes in are very convenient), two or three empty six ounce medicine bottles with good corks, a two or four HOMEWARDS. KARL GREGER. ALPINfc PHOTOGRAPHY. 1J Ounce measure, a washing rack with a trough (there is a folding rack in the market which answers admirably ; it has v shaped grooves which never damage the edges of the film, and one rack will take twenty-two glasses back to back). A zinc trough can be made to cover the plates with water when in the rack, a lantern (by ^preference a paper folding one), a dusting brush, a couple of dusters, and blotting paper cut into squares the size of the plates, with which to pack them it is useful also to have spare pieces of blotting paper to place beneath the plates when drying, also a piece of mackintosh to place on the wash stand during developing operations an empty pint wine bottle will be got at any hotel and in this the hyposulphite can be dissolved. The list looks formidable but the whole can be readily packed in the hamper of the size given. It will be seen that no intensifying solutions are enumerated amongst the requisites. A negative is better strengthened in the quiet of one's dark-room at home. Now we must give a hint or two as to the exposures required. We will suppose that on the plates to be used a satisfactory negative of an open English land- scape, on a bright June day with fleecy clouds in the sky, can be secured with an aperture of f/n in -g^-th of a second. If that be so, then on an equally fine day in July or August, at an altitude of about 6000 feet, the same kind of view should theoretically be secured in J^th second, and a stop of//i6 that is, the photographic light is about four times as strong. It must, however, be recollected that at this altitude, and particularly near mid-day, the shadows are not illuminated to the same degree from the sky. The darksr blue sky shows that the light which at a low altitude goes to make a pale blue sky is to be found in the direct rays of the sun, and not scattered to give a luminous sky. As the i8 BARNET BOOK OF PHOTOGRAPHY. shadows are principally illuminated by the light from the sky, it follows that the shadows will be darker at a high than at a low altitude, for this reason amongst others, the exposure should not be curtailed to the amount given above. If the aperture be reduced to//i6 it is probable that the exposure of ^th second will be not more than sufficient to give. For our own part we prefer to give longer and to expose well for the deep shadows, trusting to development to give us properly "gradated" pictures. As the sun goes down toward the horizon, the shadows get more illumined from local reflection, and it is scarcely necessary to alter the exposure until consider- ably nearer sunset than at home, when the exposure must be considerably prolonged. For views in which there is little but ice and snow, the exposure should be very much curtailed. There is so little contrast that if the exposure be at all prolonged the picture will be inevitably flat. The shadows are illumined by an immense quantity of light reflected from the white surface, and the difficulty is to get sufficient contrast. The writer well remembers one set of beautiful views, taken from the top of a mountain some 10,000 feet high, where the eye could see nothing but snow-fields and ice and swirling masses of clouds. The day was not bright, but to get a satisfactory picture a stop of //32 was necessary with only an exposure ofy^th of a second. Plates given an exposure of / th second with a stop //i 6 showed little besides a plain white mass. It would be difficult to give hints for every kind of view. The judgment of the operator must be brought into play and no actinometer will be of much use under the varied conditions which are the rule, not the exception. Now as to development. The "one-solution" given by the metol and amidol cartridges are the most readily prepared, and in five times out of six will scarcely be ALPINE PHOTOGRAPHY. IQ bettered, but for the sixth time may fail, because of their " rigidity." For these exceptional negatives, solutions of an oxidizing agent such as pyrogallol, of a restrainer (bromide), and of an accelerator are to be recommended. For the latter, the carbonate (not the bicarbonate) of potash is much to be recommended, though some prefer ammonia. Two formulae are given, either of which will be found extremely useful. When the exposure has been prolonged enough for details in deep shadows to be brought out, it will generally happen that over- exposure has bsen given to the high -lights, and it is to keep these in the printing state that care is required. In the old collodion dry plate days, it was very usual to bring out a complete phantom image of a subject before any density was given to it. When this was properly out, the intensiner of silver nitrate and pyrogallol was applied, and the picture gradually brought up to printing density. It was usually full of detail in the high-lights and shadows, all of which would be found in the finished print. Such is the same procedure which we recommend, strive to get out an image of feeble density but full of detail, and then give the density. The plate should first of all be thoroughly soaked in a solution of the alkali which can be used, and then a few drops of the pyrogallol solution be dropped into the developing cup with an equal number of drops of the restrainer. The alkaline solution is then returned to the cup and again poured into the dish and over the plate. By degrees the required phantom image will make its appearance, and now bromide and pyrogallol are added until it is evidently complete. The plate is then washed in water, a final wash being given in a very weak solution of acetic acid or citric and water. After a final rinse with water the plate is treated with the pyrogallol solution and restrainer in the proportion recommended 20 BARNET BOOK OP PHOTOGRAPHY. for the ordinary development of the plate, omitting the alkali. The density will begin to appear, and when it flags, a little alkali is added (a few drops at a time) to the solution. Keep the image fairly feeble at above half the proper printing density, and fix. The plate should then be kept for intensification, preferably by Mr. Chapman Jones's, when a mercury solution is applied, and then a ferrous oxalate to reduce the latter to the metallic state. It will be found if this procedure is adopted, that the negative is built up with a greater range of light gradation than by bringing it out by a one -solution method of development. If one wishes to exercise artistic treatment, then in the preliminary stage more importance can be given to any desired part by applying a camel's hair brush soaked in normal pyrogallol solution with its restrainer. The prominence thus gained will be kept in the subsequent operations. When applying the brush care must be taken that the image blends as it were with the rest of the picture. No abrupt increase of density must be permitted, as if it be, the result will be anything but satisfactory. The following is an ammonia-pyro developer, with which the writer usually works. A Ammonia i part. Water 9 parts. (Of course, should the ammonia be taken half strength allowance must be made for the dilution.) B Potassium bromide 20 grains. Water i ounce. (When travelling it is very convenient to have the bromide weighed out into 20 grain packets.) P Pyrogallol dry. S Saturated solution of sulphite of soda. ALPINE PHOTOGRAPHY. 21 When the view has strong contrasts and the plate has been exposed for the shadows take of A 30 minims and 2 ounces of water and soak the plate in it as given above. Then add to the cup, of B 2 drams, of S i dram, and about quarter grain of P. Pour back the solution of ammonia from the dish, and then apply the mixture till all detail appears, and proceed as indicated above. A saturated solution of potassium carbonate may be substituted for the ammonia solution. Before closing this chapter it may be of use to the reader to tabulate the number of thicknesses of atmos- pheres through which light has to travel at different altitudes of the sun at sea level. Altitude. Atmosphere. 90 .. i-ooo 80 1-015 70 1-064 60 1-155 50 1-305 40 1-555 30 1-995 20 .. .. .. 2-904 15 3-809 10 5-57I 5 10-216 4 12-151 .2 18-882 o 35503 If sunlight outside the atmosphere be represented by i and say T \jth be cut off by i atmosphere, then after transmission through 2 atmospheres only -81 will reach the spectator, and if through 3 only -729. For any atmos- phere the diminution will be -^th, that is, it will be -9* where x is the number of atmospheres. If we ascend the factor varies, there are less thick- nesses of atmosphere to go through and we get the following table. 22 BARNET BOOK OF PHOTOGRAPHY. irometer Visual Transmission (Sunlight outside Photographically Aainic Light Transmitted i Inches. the Atmospheric being i). (Sunlight outside the Atmospheric being i). 30 -853 '639 20 866 28 871: 672 27 884 689 x / 26 '891 . -708 800 / ^ 2 4 -008 746 23 QTR /T- U 763 22 -922 / W J -787 21 -928 -800 20 -934 '819 19 -940 -833 This table and the preceding one will enable a calculation to be made as to the exposure to be given. Thus at sea level with a photographic brightness of sun of 639,000 candles when nearly overhead, it will at 5 above the horizon only have a photographic bright- ness of about 1000. . At about 9000 feet high the photo- graphic brightness would when the sun is overhead be about 800,000 candles, and at 5 it would have a value of 350,000, showing the greater penetration through the thinner atmosphere. W. de IV. Abney, C.B., F.R.S., etc., etc. 2 3 Negative Making. DE VEL OPMENT, INTENSIFICA TION, REDUCING, Etc. MH E N a sensitive plate has been properly exposed under ordinary conditions, there is no visible change. The action of light produces what is known as a latent image or developable image, and in order to convert this into a visible image with sufficient opacity to be useful for printing pur- poses, it must be developed. In the operation of develop- ment, the plate is treated with some solution that will act on the exposed parts of the sensitive film and reduce the silver salts contained therein to metal- lic silver, in quantity pro- portional to the amount of light-action, whilst at the same time it produces no appreciable change in those parts of the film on which 24 BARNET BOOK OF PHOTOGRAPHY. light has acted the least or not at all, and which corres- pond to the darkest shadows of the object that has been photographed. The solution used for this purpose is called the developer. DEVELOPERS GENERAL. The substances that can be employed as photo- graphic developers are now somewhat numerous, but the most useful for negative making are pyrogallic acid (also known as pyrogallol, or for brevity as pyro.), ortol, metol, and hydroquinone (also known as quinol). Ferrous oxalate is likewise used in special circumstances, but not for general work. An ordinary developer as mixed for use contains i. One of the above-mentioned substances (pyrogallic acid, ortol, metol, quinol) which is the actual developing constituent, and is known as the reducer, but requires the addition of the next constituent before it can work. 2. An alkali, which may be sodium carbonate, potassium carbonate, caustic soda, caustic potash, or, if pyrogallic acid is used, ammonia. The alkali sets the reducer in action and is called the accelerator. 3. A soluble bromide, which must be potassium bromide except when ammonia is used as the alkali, and then it may be ammonium bromide. The chief use of the bromide is to retard the action of the developer, and in particular to prevent its affecting those parts of the film that have not been acted on by light. For this reason the bromide is called the restrainer or, sometimes, the retarder. M Cd r* % NEGATIVE MAKING. 25 4. A sulphite, the function of which is to prevent the solution from becoming strongly discoloured and consequently staining the film. It also affects the culour of the reduced silver that forms the developed image, this colour being browner, and consequently of higher printing opacity, the lower the proportion of sulphite present. Sodium sulphite and potassium metabisulphite are the most commonly used. The composition of a developer has to be so arranged that, whilst reasonably rapid in its action, it is not so rapid as to be beyond control, and does not produce "general fog" by acting on those parts of the film that have not been acted on by light. DEVELOPMENT GENERAL OPERATIONS AND PHENOMENA. A developer is usually compounded immediately before use by mixing two or more solutions, and in order to ensure uniform action it is essential that the constituents should be thoroughly mixed before the liquid is applied to the plate. If the measuring or mixing vessel is large enough, this can be done by agitating the liquid ; if not, the liquid may be poured once or twice from one vessel to another. The quantity of developer necessary for a plate of a given size depends in some degree upon the size and character of the dish that is used, and is smallest when the bottom of the dish is quite flat and has no ridges or grooves. It is false economy to use too small a quantity, and it may be taken tha/t for a quarter plate i^ oz., for a half plate i\ or 3 oz., and for a whole plate 4 oz. of developer should be used. Ebonite, xylonite, or papier ma-cbe dishes are the best for all operations connected with negative making, 26 BARNET BOOK OF PHOTOGRAPHY. since they are not so liable as porcelain or earthenware to break a plate if it is allowed to drop into them. When applying the developer to the plate it is important to cover the whole surface of the plate rapidly and in such a manner as to avoid the formation of air bubbles, and the best way is to begin to pour on the developer at one corner of the developing dish and whilst pouring somewhat quickly move the vessel rapidly but steadily along the edge of the dish to the other corner. If there should be any froth or air bubbles on the surface of the developer, the last portions should not be poured out of the vessel into the dish, and then the risk of air bubbles forming on the surface of the plate will be lessened. Sometimes after the developer has been poured on and the plate seems to be uniformly wetted, the liquid will recede from one corner or one edge of the plate and the part thus left uncovered will appear as a patch of lower opacity when the negative is finished. This happens either because the dish is not standing level on the table or because the bottom of the dish is not flat ; sometimes it happens because too small a quantity of developer has been used. After the plate has been covered by the developer the dish should be carefully rocked from time to time, and, for reasons that will be. explained presently, the time required for the first appearance of the image and the manner in which the different parts of the image follow one another, should be carefully observed. If the plate has been correctly exposed, the brightest parts of the image will appear (as black, of course,) in about a minute, more or less, according to the tempera- ture, composition of the developer, and character of the plate, and the other parts will follow steadily in the order of their brightness, after which the image as a NEGATIVE MAKING. 27 whole will continue to gain vigour or opacity up to a certain limit. The essential point is that the principal details in the deepest shadows of the subject shall appear and acquire a distinct printable opacity, before the highest lights become so opaque that the details in them are no longer distinguishable. Whether this con- dition is realisable or not depends very largely on the exposure that the plate has received. If the image appears in considerably less than a minute and the different parts follow one another very quickly, the plate has been over-exposed, and the degree of over-exposure is indicated by the rapidity with which the image appears. In this connection it ought, however, to be stated that with metol and certain other developers, even when the plate has been correctly exposed, the different parts of the image appear almost simultaneously, though the first appearance may not begin until about a minute after the developer has been applied to the plate. It follows that with these developers it is difficult to recognise over-exposure, but it so happens that they are not suitable developers to use when there is any probability that the plates have been over-exposed. On the other hand, if the image is slow in appearing and the brightest parts of the subject are not followed in due course by the middle tones, the plate has been under-exposed, and there is considerable danger that the high-lights may become quite opaque before any details have appeared in the shadows, or even, in extreme cases, in the lower middle tones, that is to say, in those parts that are next in darkness to the shadows. When it is desired, as it frequently is, to alter the composition of the developer during development, the substance or substances to be added should be put into the measuring or mixing glass, the developer poured out 28 BARNET BOOK OF PHOTOGRAPHY. of the dish into the glass, and the well-mixed liquid poured over the plate as before. Any attempt to add substances to the developer whilst it is in contact with the plate will probably result in uneven action. It should be borne in mind that temperature has an important influence on development, the time required for the first appearance of the image and for the com- pletion of development being, as a rule, less the higher the temperature. Further, if the developing solutions are very cold, it is often almost impossible to obtain sufficient opacity. Perhaps the most difficult thing in connection with development is to know when to stop the process, that is to say, when the image has acquired sufficient opacity, or "density," as it is often called. After all the required detail has become visible, the plate from time to time is lifted carefully out of the developer, allowed to drain for a moment or two, and then held between the developing lamp and the eye ; the opacity of the image, especially in the highest lights and deepest shadows, being carefully scrutinised. The appearance of the image as seen when looking at the back of the plate, is also carefully observed. For this purpose it is very much better that the light of the developing lamp should pass through trans- parent glass (ruby or deep orange) so that the flame itself is distinctly visible, instead of through ground glass or a coloured translucent fabric. Further, the flame of the lamp, whether gas or oil, should always be turned up to the same height, for it is clear that if the brightness of the flame used for making the examination is not fairly constant, all sorts of variable results will be obtained. For this reason it is much better to judge the opacity of negatives by artificial light than by daylight, the' intensity of the latter being so variable. KEGAtlVE MAKING. 2Q A paraffin lamp with a circular wick and a deep ruby chimney with a metal cap at the top, answers admirably. No general rules can be laid down ; the appearance of the properly developed image depends on the thickness of the film, the granularity of the silver salt, the presence or absence of silver iodide, and the composition of the emulsion used. Experience only is of value, and the best way to secure uniformly satisfactory results, is to keep as far as possible to one brand of plates. With some plates, for example, very little of the image should appear at the back of the plate, with others the greater part of the image must be distinctly visible there. Sometimes, especially when using small sizes of plates, it is not easy to tell whether all the necessary detail in the shadows has been brought out, and this is an important matter, for if the small negatives are to be used for making enlarged negatives or prints, or lantern slides, there should be very little clear glass indeed even in the deepest shadows of the subject. As a rule it may be said that when every part of the image is at least gray the maximum possible amount of detail has been brought out. If the greyness begins to spread to the margins of the plate where it has been protected by the rebate of, the dark slide, general fog is being produced, and, as a rule, little will be gained, but much may be lost, by continuing the development for any considerable time after this is observed. When development is completed the developer is poured off, the plate is well rinsed under the tap or in two or three changes of water, and is then ready for fixing. DEVELOPMENT WITH PYRO-AMMONIA. This method of development has the advantage that the constituents can be kept in concentrated solutions, considerable modifications in the composition of the 30 BARXET BOOK OF PHOTOGRAPHY. developer can be made very readily and the negatives obtained are of excellent printing quality. On the other hand it cannot be satisfactorily employed with certain brands of rapid plates, because with them it has a tendency to produce general fog, and with some other plates, especially when they are old, it has a tendency to produce what is known as green fog. Three solutions are prepared : REDUCER. Pyrogallic acid i oz. or 10 parts Potassium metabisulphite* .. i oz. or 10 parts Water, to make up to 10 oz. or 100 parts ACCELERATOR. Ammonia i oz. or 10 parts Water, to make up to 10 oz. or 100 parts RESTRAINER. Ammonium bromide i oz. or 10 parts Water, to make up to 10 oz. or 100 parts For each ounce of developer, take 20 minims of reducer, 20 minims of restrainer and 40 minims of accelerator, and make up to i oz. with water. With some plates 60 minims of accelerator and 30 minims of restrainer may be used, but any greater proportion of accelerator has considerable tendency to produce general fog. On the other hand the proportion of restrainer can often be increased with advantage since, unless the amount added is very large, its chief effecl is to prevent general fog ; 30 minims of restrainer to 40 minims of accelerator, or 40 minims of accelerator to 60 minims of restrainer are proportions that can be recommended. Too low a proportion of bromide should be carefully avoided. * The metabisulphite is dissolved in about 8 oz. (80 parts) of water with the aid of heat, and the pyrogallic acid is then added. When the liquid has cooled it is made up to 10 oz. (100 parts) by addition of water, the whole being well mixed by shaking. NEGATIVE MAKING. 31 It is very important to ascertain, by careful trial with each brand of plates that is to be used, what is the maximum proportion of ammonia that can safely be added, and what proportion of bromide to ammonia is necessary in order to prevent general fog. As a rule, the more rapid the plates the smaller is the quantity of ammonia that can be used with safety. By far the best plan is to keep development well under control by adding only part of the accelerator at the beginning of development and adding the rest as circumstances require. For each ounce of developer take 20 minims of pyro. solution and make up to the required bulk with water. In another measure mix for each ounce of developer 40 minims of bromide solution and 60 minims of ammonia solution, and regard this as the maximum quantity that can be added with that bulk of developer. Now to the diluted pyro solution add about a quarter or one-third of the ammonia and bromide solution, pour this mixture on the plate and observe what happens. If the mode of appearance of the image indicates that the plate has been correctly exposed, about half the remaining ammonia and bromide mixture may be added to the developer at once, and the action allowed to con- tinue, with occasional rocking of the dish. If develop- ment proceeds satisfactorily and, in particular, if the chief details in the shadows begin to appear before the highest lights have become too opaque, it is not necessary nor advisable to add the last portion of the ammonia and bromide mixture, since the tendency to general fog and green fog is reduced when the proportion of am- monia is kept as low as possible. On the other hand, if the development flags and the appearance of shadow detail is a little tardy, the rest of the ammonia and bromide mixture must be added. 32 BARNET BOOK OF PHOTOGRAPHY. If the plate seems to be over-exposed, no more of the ammonia and bromide mixture should be added f^r some time, until it is seen whether the quantity already in the developer will suffice to complete development. If it seems that the over-exposure has been considerable, a further quantity of pyro solution (10 to 20 minims per oz.) and also of bromide solution (10, 20, or 30 minims per oz.) may be added with advantage. Development is then allowed to continue and the negative is examined from time to time ; if it is seen that the opacity does not increase, or if sufficient detail in the deep shadows does not appear, further small quantities of the ammonia and bromide mixture may be added cautiously until the required result is obtained, waiting a little while to see the result of each small addition before adding more. When the plate behaves as if under-exposed, dilute the developer at once with half the quantity or an equal quantity of water, according to the degree of under- exposure indicated, and add the whole of the ammonia and bromide mixture. These modifications should check the rate at which the high-lights of the subject gain opacity, whilst accelerating the appearance of the middle tones and shadows. Should this effect not be produced, further quantities of ammonia and bromide mixture may be added or, in extreme cases, ammonia alone, and the developer may be still more diluted with water. If any considerable parts of the image still show no detail, local development with a brush may be tried as a last resource. A soft camel's hair brush, preferably mounted in quill, is used. Some of the ammonia and bromide mixture is placed in a vessel and diluted with two or three times its volume of water. One corner or edge of the plate is raised so that the part to be treated is lifted <^ut of the developer, the diluted ammonia and NEGATIVE MAKING. 33 bromide mixture is applied rapidly with the brush, and the plate is allowed to drop gently back into the developer. The treatment may be repeated if necessary. Should all these devices fail, the plate is hopelessly under-exposed. Sometimes, when working with a diluted developer as jus!, described, it happens that although all the necessary detail has been brought out, the image gains in opacity very slowly. Provided that all the required detail is visible, small quantities of pyro solution may be added in order to gain opacity more quickly. PYRO-SODA DEVELOPMENT. When sodium carbonate is used as the alkali in place of ammonia the developer acts somewhat more slowly and is less liable to produce fog, es- pecially with very rapid plates, and there is very little tendency to produce green fog. On the other hand, variations are not so easily made in the com- position of the developer. Some people find the absence of the smell of ammonia a decided advantage. TEASELS By Carine Cadby. 34 BARNET BOOK OF PHOTOGRAPHY. STOCK PYRO SOLUTION. The same as for Pyro-Ammonia. DILUTE PYRO SOLUTION. * Stock pyro-solution i oz. or 10 parts Water 10 oz. or 100 parts SODA SOLUTION. Sodium carbonate, crystallised, i oz. or 10 parts Sodium Sulphite i oz. or 10 parts Potassium bromide 10 grains or 0^23 part Water to make up to f 10 oz. or 100 parts For use mix equal parts of dilute pyro solution and soda solution an-d pour over the plate. If the exposure has been correct the image will begin to appear in about a minute, and development is then allowed to go on with occasional rocking of the dish, until the negative is sufficiently opaque. If the plate behaves as if it were under-exposed, at once dilute the developer with an equal bulk of water and pour it back over the plate. If the high-lights continue to increase in opacity, but the rest of the image does not appear, add some more of the soda solution with or without some more water. Should parts of the plate still remain blank, apply some of the soda solution to them with the aid of a brush as described under pyro-ammonia (page 32). If the rapid appearance of the image indicates that the plate is over-exposed, at once pour off the developer into a measure or mixing glass and rinse the plate well with water. Add to the developer a small quantity of potassium bromide solution (i in 10 of water) which should be kept at hand for this purpose. A small quantity of pyro stock solution may also be added. The * No more of the dilute pyro solution should be made up than is likely to be used during the same day, but it will keep well enough for a day or two. f The sodium sulphite and carbonate are dissolved, with the aid of heat, in about 8 oz. (80 parts) of water, the bromide added, and the liquid when cold made up to 10 oz. by adding water. NEGATIVE MAKING. 35 developer is then poured over the plate again. When the over-exposure seems to have been considerable, the amount of potassium bromide added may amount to 4 grains (or 40 minims of the i in 10 solution) per ounce of the developer, but this proportion should not be exceeded ; even small quantities of bromide in the pyro-soda developer have a marked influence in retarding development. When there is reason to suspect over-exposure, not more than half the soda solution should be added at the beginning of development, and the rest may be added or not, as the case may require. DEVELOPMENT WITH ORTOL. ORTOL SOLUTION. Ortol 130 grains or 1-5 parts Potassium metabisulphite* 65 grains or 075 part Water to make up to .... 20 ounces or 100 parts SODA SOLUTION. The same as for pyro-soda. Mix equal parts of ortol solution and soda solution. This developer behaves in much the same way as pyro-soda and gives very similar results. It has the advantage, however, that it does not stain the fingers, and has practically no tendency to- produce either fog or stain on the plates. Moreover the same quantity of solution can be used for several plates ; when the action becomes perceptibly slower or weaker, part of the old solution is poured away and an equal quantity of freshly mixed ortol and soda solutions is added. The chief differences to be observed are (i) that the different parts of the image follow one another more rapidly than with pyro-soda, even though the plate may have been correctly exposed, and (2) the colour of the reduced silver is somewhat bluer than with pyro-soda, * See foot-note to page 30. 36 BARNET BOOK OF PHOTOGRAPHY. and therefore in order to obtain the s~une degree of printing opacity, as distinct from visual opacity, develop- ment must be carried a little further. Apart from these differences, what has been said of pyro-soda holds good for ortol soda and need not be repeated. DEVELOPMENT WITH HYDROQUINONE (QUINOL). QUINOL SOLUTION. Hydroquinone 90 grains or 2 parts Sodium sulphite i oz. or 10 parts Water to make up to. ... 10 oz. or 100 parts ALKALI SOLUTION. Potassium carbonate (dry) i oz. or 10 parts Potassium bromide 20 grains or 0-46 parts Water to make up to .... 10 oz. or 100 parts Mix two parts of hydroquinone solution with one part of alkali solution and one part of water, or, if a more energetic developer is wanted, mix equal volumes of the hydroquinone and alkali solutions. Hydro- quinone is not an advantageous developer for general purposes, but it is useful when negatives are required showing strong contrast between the highest lights and the deepest shadows, and especially when it is important that there should be no deposit at all in the deepest shadows. This is the case, for example, when copying line engravings, pen and ink drawings and similar subjects. DEVELOPMENT WITH FERROUS OXALATE. This method of development also is not well adapted for general work, but it is invaluable for certain purposes. The reduced silver has a pure grey-black colour and there is exceedingly little tendency to produce fog of any kind. On the other hand, the NEGATIVE MAKING. 37 developer admits of little modification in its composition and therefore the exposure must be fairly correct. It is also important to avoid contamination with even minute quantities of hypo, since this substance very readily causes stains. FERROUS SULPHATE SOLUTION. Ferrous sulphate 2$ oz. or 25 parts Sulphuric acid Small quantity Water to make up to 10 oz. or 100 parts About three-quarters of the total quantity of water is mixed with a small quantity (not more than 50 minims per 10 ozs., or one part per 100) of sulphuric acid, and the ferrous sulphate (protosulphate of iron) which must be in clear pale green crystals without any yellowish incrustation, is dissolved in it with the aid of a gentle heat. After the solution has cooled, it is made up to the specified volume with water. This solution alters when exposed to air, and should, therefore, be kept in small (2 oz.) bottles, filled up to the neck and tightly corked. OXALATE SOLUTION. Potassium oxalate 10 oz. or 25 parts Potassium bromide 40 grains or 0-23 part Water to make up to . . 40 oz. or TOO parts For use take four parts of oxalate solution and one part of ferrous sulphate solution, pouring the latter into the former and not vice versa. In order to obtain slower action with a rather softer image and a slightly browner deposit, the developer may be diluted with an equal vo'ume of water. Slower action, with slightly increased printing contrasts, and clearer shadows, results from an increase in the proportion of bromide. FIXING. After development is finished, the dark-coloured reduced silver that forms the image remains mixed with a considerable quantity of semi-opaque, yellowish 38 BARXET BOOK OF PHOTOGRAPHY. unaltered silver bromide, which would not only interfere with the printing, but would also gradually darken when exposed to light. The negative must therefore be "fixed" by dissolving out the unaltered silver bromide, and this is accomplished by immersing the plate in a fairly strong solution of sodium thiosulphate (formerly called sodium hyposulphite) commonly known as "hypo." The usual strength of the fixing is as follows: FIXING BATH. Hypo (sodium thiosulphate) 10 oz. or 25 parts Water to make up to 40 oz. or 100 parts A solution of double this strength is, however, not unfrequently used, and acts more rapidly, especially in cold weather. The developed plate, after being well rinsed with water, is placed in the fixing bath and allowed to remain in it with frequent rocking until the silver bromide has all been dissolved out of the film. This is ascertained by lifting the plate out of the dish and looking at the back by reflected light, the plate being held in front of something dark. It is not difficult to see whether the silver bromide has all disappeared or not, but in order to ensure complete fixing the plate must not be taken out of the bath as soon as this has happened, but should be left in for a few minutes longer, the dish being rocked so that the dissolved silver salt may diffuse out of the film into the fixing bath. When removed from the fixing bath the plate should be allowed to drain into the bath for a few moments and should then be washed for five or ten minutes in running water under the tap. It is best to put the plate in a dish standing on the sink and have a piece of flexible indiarubber tubing reaching from the tap to within a couple of inches or so of the top of the dish, so that the water may not splash too much. NEGATIVE MAKING. 39 After washing in this way, the plate is placed in a grooved zinc rack, which is immersed in a tank (prefer- ably of zinc), containing sufficient water to completely cover the plates, and here it remains until the whole batch of plates in hand has been developed and they can all receive their final washing together. The plates stand upright in the rack, and the entrance and exit of the water must be so arranged that the water enters at the bottom and overflows at the top, or, what is perhaps better, enters at the top and is drawn off from the bottom, the waste pipe opening at the bottom of the tank and being bent and carried upwards until its mouth is at the level at which the water is to stand in the tank. When running water is not available the plates may be washed in dishes. After being well rinsed to remove the adhering hypo solution, the plate is covered with water (about 3^ oz. for a half plate or 5 oz. for a whole plate) and allowed to remain with frequent rocking for five or six minutes. The water is then well drained off, a second quantity added and allowed to remain for the same time as before, with frequent rocking, when it is poured off in its turn. Treatment in this way with six successive quantities of water will remove all the hypo, provided that the film has not been treated with alum. Another plan, rather less troublesome, but also less expeditious, is to place the rack containing the plates in a tank not much more than big enough to hold it, taking care that there is not less than two inches between the lower edges of the plates and the bottom of the tank. After standing for some time the rack and the plates are slowly and carefully lifted out and allowed to drain, the tank emptied and filled with fresh water, and the rack and plates then replaced. Eight or 40 BARNET BOOK OF PHOTOGRAPHY. ten successive quantities of water applied in this way should remove all the hypo, but if there is any doubt on this point the plates, after they are supposed to be washed and have been removed from the tank, should be allowed to drain into a measuring glass or into a dish, the contents of which are afterwards transferred to a measuring glass and mixed with a small quantity of a solution of silver nitrate. If the plates are really com- pletely washed nothing will happen, or at most a white precipitate will be produced which will remain white if not exposed to daylight. If, on the other hand, the plates still retain hypo, the silver nitrate will produce a precipitate which will gradually become orange and eventually dark brown. Should this happen, the washing must be continued. DRYING. If the negatives are allowed to dry in the rack in which they were washed, the process is slow, and sometimes if the washing has not been complete, the middle portions of the negatives, which dry last, are less opaque than the rest. An excellent method of drying negatives rapidly and in such a way that no dust can fall on the film, is to drive nails (preferably of copper) into a wall or aboard fixed against the wall, at distances apart depending on the size of the plates Each plate WINTER TIME ON THE ALPS. CAPT. W. DE W. ABNEY, QB., F.R.S., ETC. NEGATIVE MAKING. 4! then rests, with the film downwards, between a pair of nails, the lower corner of the plate resting against the wall, as shown on previous page. ALUM BATH. It is frequently recommended that all plates should be immersed in a strong solution of alum, for the purpose of preventing "frilling" by hardening the film. Its use is, however, attended with the great disadvantage that liquids diffuse into and out of a film so treated with much greater difficulty than in the case of an ordinary film, and consequently if the film is alumed between development and fixing, the fixing is not only much slower, but the washing after fixing requires a very much longer time. If, therefore, the alum bath is used at all, it should not be applied until after the film has been well washed after fixing. The following solution may be used : ALUM BATH. Alum i oz. or 5 parts Water 20 oz. or 100 parts If a strong solution of alum is applied to the plate for a long time, the film may become so thoroughly hardened that it partially loses its adhesiveness, and there is a possibility that it will begin to peel from the glass after the negatives have been stored for some time in a dry place. The solution given above is quite strong enough and plates need not be immersed in it for more than five minutes, after which they must, of course, be again well washed. The hardening of the film, if not carried too far, no doubt makes it less liable to be injured by abrasion and the like. FRILLING. It sometimes happens that during the various operations of development, fixing and washing, the film begins to leave the plate and rise in puckers along the edges. This is known as "frilling," and in bad cases it may spread until a large part of the film 42 BARNET BOOK OF PHOTOGRAPHY. has detached itself from the glass. It is due to excessive or irregular absorption of water by the gelatine, and at one time was commonly met with, but it rarely occurs with the dry plates of the present day. It is most likely to arise if there is any considerable difference of temperature between the various liquids and the wash- water, or during very hot weather when all the liquids are much warmer than usual. When frilling does occur, the plate must be treated carefully, so as to avoid tearing the film, but unless it is very bad and shows a tendency to spread, all the operations, including washing after fixing, should be completed before any special measures are taken to remedy the defect. On the other hand, if the frilling spreads rapidly, the plate should be carefully rinsed two or three times with water and placed for five minutes in the alum bath, with occasional gentle rocking, after which it is again well washed to remove the alum, and the various operations are completed. There is one exception to the procedure just indicated; if the frilling becomes bad while the plate is being fixed or during washing after fixing, the alum must not be applied until the fixing and the washing after fixing are completed. If something must be done in these circumstances, the plate, after draining, but without any previous washing, may be placed for about ten minutes in a saturated solution of common salt. It can afterwards be put back into the fixing bath, also without any intermediate washing, and the remainder of the process carried through. Although the methods just described will check the frilling, they will not remove its effects. For this purpose the plate after its final washing is allowed to drain thoroughly and is then immersed in methylated alcohol, preferably of the old kind, though the new kind NEGATIVE MAKING. 43 can be made to do. The alcohol abstracts water from the film, which consequently shrinks to its original size and can be pressed back with the fingers into its proper position on the plate. Should the film be opalescent it should be removed from the first quantity of alcohol and placed in a second quantity, after which it should be set up to dry. The plates should not remain too long in the alcohol or the gelatine will contract too much. DEFECTS IN NEGATIVES. A perfect negative presupposes a perfect plate, correct exposure, and correct development stopped at exactly the right time. It is almost unnecessary to say that all these conditions are rarely satisfied, and conse- quently most negatives fall more or less short of perfection. The defects may be broadly grouped under two heads, namely, those due to imperfections existing in the film before exposure, and those due to defects or errors in the way in which the plate has been treated. It will be more convenient to deal with the latter, and larger, group first, but there is really no hard and fast division between them. THE NEGATIVE is THIN, or in other words, whilst showing good gradation, and sufficient relative contrast between the different parts, is as a whole lacking in opacity or printing strength, and gives prints that are deficient in vigour and contrasts. The plate has been removed from the developer too soon, and the remedy is to intensify the image (see p. 51). Sometimes the want of opacity is due to the fact that the developer was too cold. THE NEGATIVE is TOO DENSE OR OPAQUE and consequently although showing good contrasts and gradations, takes a long time to print, especially on dull days. The developer has been too energetic, or 44 BARNET BOOK OF PHOTOGRAPHY. development has been continued too long ; the remedy is to reduce the image (see p. 50). THE IMAGE is "FLAT," or shows comparatively little contrast between the highest lights and the deepest shadows. This may, of course, be due to the absence of contrasts in the subject photographed ; it is commonly due to over-exposure ; it may be caused by using a developer containing too little reducer, or restrainer, or both, and too much alkali ; sometimes it arises from a defect in the quality of the emulsion, or from the fact that the plate has been coated with an abnormally thin film of emulsion. THE IMAGE is " HARD," or shows excessive contrasts between lights and shadows, and is defective in the range of its half-tones. This is probably due to under-exposure, but may have been aggravated by the use of a developer containing too much bromide or too little alkali. Local reduction (see p. 50) may partially remedy the defect. FOG. A more or less marked grey deposit of reduced silver extends over the whole surface of the image. It may be due to over-exposure, in which case the edges of the plate that have been protected by the rebate of the dark slide usually remain clear. It may also be caused by using a developer containing too much alkali, or too little restrainer, or both, or by the plate having been exposed to actinic light outside the camera, including the light from the dark-room lamp if the glass or coloured fabric used as the screening material is not efficient. In any of these cases the defect would be observable up to the extreme edges of the film. The character of the dark-room light should be tested by exposing one half of a plate to it at a distance of say nine or twelve inches for five or ten minutes, the NEGATIVE MAKING. 45 other half of the plate being protected by some opaque substance. The best plan is to put the plate into a dark slide and draw out the shutter half-way. After exposure the plate is treated with a developer in the usual manner, and it can then be seen whether or no the light has exerted any action on the plate. Slight general fog may as a rule be neglected, but if the amount of fog is at all considerable the plate should be treated with a reducer, and afterwards the image can, if necessary, be intensified. GREEN FOG. The surface of the film shows a peculiar brilliant green or yellowish-green lustrous appearance, generally in patches, when examined by reflected light, but is more or less distinctly pink when the plate is looked through. This effect is rarely observed except when pyro-ammonia has been used as the developer, and it most frequently occurs with old plales, especially if development has been long continued or has been forced by the addition of comparatively large quantities of ammonia. If the green fog is only slight it does not affect the prints made from the negative, but in bad cases the prints have a patchy appearance and are less deeply printed at those points where the green fog is worst. Two metho'ds are available for the removal of green fog. In one of these the plate, after being fixed and washed, is placed in a hypo solution of half the strength of the ordinary fixing bath, and to this hypo solution is added a very small quantity of a solution of potassium ferricyanide, and the mixture is allowed to act on the plate for some time, the dish being rocked occasionally. The green fog will gradually disappear and some more of the ferricyanide may be added, if necessary, to secure this end, but it is important to keep the proportion of ferricyanide as low as possible, otherwise the image 46 BARNET BOOK OF PHOTOGRAPHY. itself will be reduced. For this reason, if it is seen or suspecfled that the green fog is likely to be bad, develop- ment should be carried a little farther than usual in order to allow for the slight reduction that accompanies the removal of the green fog. The other plan is to immerse the plate in a dilate solution of ferric chloride (perchloride of iron) until the green fog has been completely bleached, then wash, first in a dilute solution of oxalic acid and afterwards in water, and finally treat with a developer, preferably ferrous oxalate. The green fog is converted into a very fine grey deposit which is almost invisible and has no appreciable effect on the priming qualities of the negative. BLACK SPOTS may be due to particles of dirt that have been allowed to lodge on the film during one or other of the operations, or during drying. They may also be due to particles in the emulsion, and in the latter case are generally round and sharply defined. BLACK MARKS of the nature of irregular streaks, looking, so to speak, like black scratches, are generally due to mechanical abrasion of the film. Pressure produces a developable image similar to that produced by the action of light. BLACK BANDS, indistinct or nebulous at the edges, are sometimes caused during the coating of the plate with the emulsion, in which case they, as a rule, extend all the way along or across the plate. More commonly they are due to defects in the hinges of the dark slides, which may produce the bands either by allowing light to pass through, or by giving off exhalations that affect the plates if they are allowed to remain in the dark slide for a long time. If the bands are due to the hinges, they will, of course, correspond with them in position, and if the hinge is double, in the distance between them. NEGATIVE MAKING. 47 TRANSPARENT BANDS, or bands showing less opacity than the rest of the image, are sometimes caused by exhalations from the material forming the hinges of the dark slides. TRANSPARENT SPOTS if small ("pinholes"), are gen- erally due to the presence of particles of dust on the surface of the plate when it was exposed. Prevention lies, of course, in carefully dusting the plate and the dark slide with a soft, clean, dry camel's hair brush, before putting the former into the latter. If the spots are larger and circular, they are due either to the formation of air bubbles on the surface of the plate during development, or to the presence in the film of insensitive particles. UNEVEN OPACITY OR DENSITY, varying gradually from one end or side of the plate to the opposite end or side, is due to uneven coating of the plate. If there is a distinctly defined patch, less opaque than the rest, the plate was not properly covered by the developing solution. STAINS. A uniform stain, of a yellowish or brown colour, is produced when the pyro developer contains too small a proportion of sulphite or is allowed to act for a very long time. Such a stain is rarely observed with the other developers mentioned above. The pyro stain can be more or less completely removed by immersing the plate for some time, with repeated rocking, in the alum solution given above, i drachm of sulphuric acid being added to every 10 ounces. The plate must after- wards be well washed in soft water. Similar stains in patches may be caused by using dirty dishes or a de- veloper that has become turbid by being frequently used. DEEP YELLOW-ORANGE OR BROWN STAINS, appearing gradually in patches or all over the negative, some time after it has been fixed, and washed, and dried, are due either to imperfect fixing or to incomplete washing after fixing. There is no practicable remedy. 4 8 BARNET BOOK OF PHOTOGRAPHY HALATION. When the subject photographed in- cludes some part much more brightly lighted than the rest, such as a window in an interior subject, the details of the bright part are not only lost, but the image of it seems to spread in all directions, obliterating the details of the sur- rounding portions. The effect is especially noticeable when the subject includes dark parts which necessitate a somewhat long ex posure. A window at the end of a long dimly lighted interior, or -C dark trees against a bright sky are cases in point. The effect is really due to the fact that the sensitive film is not perfefily opaque, and some of the incident light passes through the film and is reflected from the back surface of the glass on to the under side of the film, producing a blurred image superposed, as it were, on the normal image formed at the surface of the film by the action of the direct light. The effect is known as "halation." It is pre- vented by having a perfectly opaque film, which is a condition difficult to realize in practice, and which, moreover, introduces cer- tain other disadvantages. It is also prevented by coating the back of the plate with some substance that will absorb the rays that have NEGATIVE MAKING. 49 passed through the film, and so prevent their being reflected back against the under side of the film. The substance used must either be opaque or must have a deep orange, brown, or red colour, and it must have the same refractive index as the glass, otherwise the reflection will not be prevented. For practical convenience it must also be easily applied and easily removed. Many substances have been recommended but nothing is so good as caramel, prepared by the action of heat on sugar. In order to get the mixture to dry completely after it has been applied, a somewhat troublesome process of purification is necessary, but caramel specially prepared for the purpose can now be obtained from dealers in photographic materials. The caramel (which is a solid substance) is dissolved in just enough water to make a thick syrup, which is carefully applied to the back of the plates in a thin layer by means of a flat brush. If the caramel does not dry properly the solution may be thoroughly mixed with about one quarter (or more) of its weight of very finely powdered burnt sienna or burnt umber, "ground in water." After being coated, the plates require some time to dry, and must, of course, be carefully protected from light. If the dark-room is thoroughly dark, the plates may be put up to dry in the same manner as negatives (see page 40), but if the dark-room is not suitable, some sort of drying box must be used. After exposure and before development the backing is removed with a damp sponge; if caramel only is used in a form completely soluble in water, it need not be removed unless a developer is being used that is to be applied to several plates in succession. REDUCTION. When a negative is too opaque or dense it must be reduced by dissolving away part of the silver that forms 50 BARNET BOOK OF PHOTOGRAPHY. the image. The same process is also applied for the removal of general fog, sometimes with a view to subsequent intensification. The simplest solution to use for this purpose is known as the Howard Farmer reducer and Is a solution of hypo mixed with a small quantity of potassium ferricyanide (red prussiate of potash). FERRICYANIDE SOLUTION. Potassium ferricyanide i oz. or 10 parts Water to make up 10 oz. or 100 parts This solution must be protected from light if it is to be kept for any length of time. The negative which, if it has been previously dried, must be soaked in water for some time until it is thoroughly and uniformly wetted, is placed in some fresh hypo solution (the ordinary fixing-bath solution diluted with an equal volume of water) to which a small quantity of the ferricyanide solution has been added, and the dish is rocked repeatedly to ensure uniform action. The rapidity of the reducing action depends on the proportion of ferricyanide solution added, and it is very important not to add too much, otherwise the process gets out of control and reduction goes too far. The image should be carefully watched and the plate removed from the solution and rapidly washed before the apparent reduction is quite as great as it is intended to be. It is much better to stop too soon than too late, because if it is found that a little further reduction is necessary, the plate can be again immersed in the hypo and ferricyanide. The ferricyanide reducer can be applied locally for reducing high-lights, halated windows, etc., and this is often very valuable, especially in the case of under- exposed negatives. A small quantity of hypo and ferricyanide solution is mixed in a measuring glass or some other suitable vessel. The plate is immersed in NEGATIVE MAKING. 51 plain hypo solution in a white dish for a short time and is then raised by one corner or one edge until the part to be reduced is above the solution. The mixture of hypo and ferricyanide is carefully applied with a camel's hair brush to the parts that are too opaque, and after a few moments the plate is allowed to slip back into the hypo solution and the dish is rocked. If the reduction is not sufficient, the same proceeding is gone through as often as necessary. The reducer should not be allowed to act too long before putting the plate back into the hypo, otherwise the reduction may spread further than is desired. Further, the reducer must not be too strong (i.e., contain too much ferricyanide), otherwise it will produce brownish stains and the action may be too energetic. The other reducer is known as Belitzski's reducer, and is made up as follows : Ferric potassium oxalate i oz. or 5 parts* Sodium sulphite i oz. or 4 parts Oxalic acid J oz. or i part Hypo solution (25 in 100) ... 5 oz. or 25 parts Water 20 oz. or 100 parts The constituents must be dissolved in water in the order given. The solution can be used at once and it keeps fairly well if protected from light, in well corked bottles filled up to the neck. INTENSIFICATION. Intensification is a process in which the opacity of the image is increased by adding some fresh matter, metallic or otherwise, to the reduced silver that constitutes the developed image. The usual plan is to bleach the image by means of a solution of mercuric chloride (mercury perchloride or * The formula in "parts" does not stridlly correspond with that in ounces, but the difference is immaterial. 52 BARNET BOOK OF PHOTOGRAPHY. corrosive sublimate), which converts the dark-coloured silver into a white mixture of silver chloride and mercurous chloride, and this is subsequently treated with some re-agent which will reconvert the image into a dark product of greater opacity than the original. It is absolutely essential to successful intensification that the negative be completely fixed and completely washed after fixing, for any trace of hypo left in the film will give rise to brown stains. It is also important, in order to prevent stains of another sort and to secure uniform action, that the mercuric chloride solution be mixed with a small quantity of hydrochloric acid. Too much acid will cause frilling. If the negative has been dried it must be immersed in water for, as a rule, not less than half-an-hour, in order that it may be thoroughly and uniformly wetted. MERCURIC CHLORIDE SOLUTION. Mercuric chloride .... i oz. or 5 parts Hydrochloric acid. ... i$ drachms or i part Water to make up to. . 20 oz. or 100 parts When uniform intensification is required the negative is allowed to remain in this solution until it is completely bleached. If, however, it is desired to intensify the shadows more than the high-lights, the plate should be removed from the solution as soon as the shadows have bleached, and should be rapidly washed in order to stop the action on the more opaque parts ot" the image. In either case the negative must be thoroughly washed after bleaching, and the water used must be soft water. Hard water tends to produce a precipitate of the mercury salt in the film, which may subsequently lead to stain or fog. Perhaps the best plan of all, when constant results are desired, is to treat the bleached negative with the ferrous oxalate developer, which will gradually convert the white image into a black one, after which the plate NEGATIVE MAKING. 53 is thoroughly washed and dried. It is recommended that the first water used for washing should be slightly acidified with oxalic acid. Instead of using ferrous oxalate the bleached plate may be treated with a weak solution of ortol or metol to which some sodium carbonate (soda crystals) solution has been added, but no sulphite. After the image has blackened completely the plate is washed. With any of these methods if the first intensifica- tion is not sufficient, the plate may be again bleached with the mercury solution and the process repeated. An old method, frequently used, is to treat the bleached plate with dilute ammonia, which converts the white image into a dark brown one of very considerable printing opacity. The results are often very good, but are somewhat uncertain, since the precise effect obtained depends on the strength of the ammonia solution and the time during which it is allowed to acl. With somewhat strong ammonia, allowed to act for a fairly long time, part of the intensification first produced is removed. This affects the shadows more strongly than the lights and the result is to increase the contrast of the negative, which is very useful for certain purposes. The negatives intensified with mercury solution followed by ammonia are more liable to spontaneous change and deterioration than those intensified with mercury solution followed by one of the developers. The latter, in fact, if properly washed, may safely be regarded as permanent. URANIUM INTENSIFIED A very considerable degree of intensification can be obtained by the use of the uranium intensifier, which is very different in its mode of action, and is a little uncertain in its results. A solution containing potassium ferricyanide and a uranium salt, generally the nitrate, is applied to the. 54 BAKNET BOOK OF PHOTOGRAPHY. negative, and a deposit of a deep orange-red colour is formed upon the silver image and very greatly increases its printing opacity. The great difficulty is to prevent this deposit forming on the whole of the film, and it is absolutely necessary that every trace of hypo should be washed out of the film. The addition of acetic acid to the solution not only promotes uniformity of action, but also helps to keep the shadows of the image clear. FERRICYANIDE SOLUTION. The same as for the ferricyanide reducer. URANIUM SOLUTION. Uranium nitrate i oz. or 10 parts Water to make up to 10 oz. or 100 parts THE INTENSIFIED Uranium solution (i : 10) i drachm or 5 parts Ferricyanide solution (i : 10) i drachm or 5 parts Acetic acid (glacial) .... 2 drachms or 10 parts Water to make up to . . 2^ oz. or 100 parts The negative is placed in this solution and allowed to remain with occasional rocking until the degree of intensification is sufficient, which can only be learnt by experience. If it is seen that the deposit is beginning to form on the clear parts of the negative, the plate should be at once removed. After intensification the plates are well washed. If the water is "hard" the intensification will be slightly reduced during washing, and this is often useful in removing a slight stain over the whole of the plate. Treatment with water containing a small quantity of ammonia or sodium carbonate removes the whole of the deposit, but leaves the original image slightly reduced and also partially altered in composition. VARNISHING. A negative after been thoroughly dried may be used for printing without any further treatment, especially if only a few prints are required and the ordinary ready NEGATIVE MAKING. 55 sensitized papers or emulsion papers are used. It is, however, better to protect the negative from mechanical as well as chemical injury by means of a film of hard varnish or collodion. Many excellent negative varnishes can now be purchased, and the general mode of application is the same. The negative must be thoroughly dry, and in order to secure this and to make the varnish flow more easily, the negative is very carefully heated in front of a fire or over a small stove until it is just warm, but not hot. The negative is best supported by means of a pneumatic holder held in the left hand, and a fairly large pool of varnish (the exact amount can only be learnt by experience) is poured on the plate somewhat towards the right-hand top corner, and by carefully tilting the plate it is made to run first to the nearest corner, then along the edge to the further left-hand corner down to the nearer left-hand corner, and back to the right-hand bottom corner, from which it is poured into a bottle. The plate is gently rocked whilst it drains into the bottle, and as soon as the varnish ceases to drop the plate is again carefully warmed until the back of it is just too hot for the back of the hand to bear, after which it is placed in a rack to cool. It is necessary that the varnish should be quite clear and free from any solid particles, and if necessary it must be filtered through a plug of cotton wool moistened with alcohol and placed in the apex of a glass funnel which is resting in the neck of a clean and dry bottle. Since dust may fall into the varnish whilst it is on the negative, it is the best plan to pour the excess of varnish off the negative into a second bottle instead of back into the first, out of which it was poured. To put it in another way, one bottle should be kept for the clear varnish, and a second bottle for the varnish poured off 50 BARNET BOOK OF PHOTOGRAPHY. the plate. When the second bottle is full, its contents are filtered into the first bottle for use again. Instead of varnish, a film of collodion, toughened by the addition of a few drops of castor oil, and known as "leather" collodion, may be used. The collodion is applied to the plate in the same way as varnish except that the plate is not warmed. C. H. Bothamky. 57 Lenses. HOTOGRAPHS of flat objects such as leaves, lace, drawings, etc., can be made by simply putting the object on the sensitive surface and exposing the arrange- ment to light. But this method will not serve if the photograph is wanted of any other size than the original, nor with solid objects of any size, except perhaps in the pro- duction of full-size profiles of faces. It is therefore quite the exception in photography to "print" directly from the object it- self, and the only alterna- t ive is to produce an image on the sensitive surface. "" All illuminated objects reflect light and so become for practical purposes sources of light, just as the moon shines, as we say, although it only shines because it is shone upon by the sun. The simplest source of light 5 BARNET BOOK OF PHOTOGRAPHY. to consider is a point of light, and if we can get a dot of light on a white surface from a point of light we have at once an image of that point of light. The smaller the dot the sharper or more perfect is the image, the larger the dot the more diffused or fuzzy is the image. It is impossible by any known means to get the dot so small that it is an actual point, that would be absolute per- fection, and on the other hand there is no size of the dot at which it can be definitely said that it ceases to be an image. Every point of an illuminated object is a point of light, and fine definition consists in keeping these points separate in the image. So far as the dots overlap they are confused. Confusion, or diffusion, or fuzziness is sometimes desirable, as for example in a portrait, which may be excellent although it is impossible to distinguish in the picture the individual hairs on the person's head. The simplest means for getting an image is a small hole in an opaque screen. In fig. i, two points of light, A and B, shine through the hole in the screen S and produce two dots of light, a and b, on the surface T. The two pencils of light do not practically interfere with each other although they pass through the same small hole, nor would any greater number; so that an illuminated object, which may be regarded as consisting of an infinite number of points of light, would give an image on the surface T. The disadvantages of a small hole, or "pinhole," for the production of images are (i) it LENSES. 59 must be so small that it lets very little light through and therefore gives a very feeble image, (2) that it can never give a sharp image. The first disadvantage is obvious. With regard to the second, a little consideration will show that the image of a point must be larger than the hole itself, it is always larger though it may have a central brighter part that is smaller. If the hole is reduced in size beyond a certain limit, it gives an increased spreading of light on the surface, so that a sharp image can never be produced. Now the function of a lens is to obviate these draw- backs as far as possible ; namely, to let more light through and form a brighter image, and to give sharper definition. In figure 2, the lens L collects all the light that fails upon it from the point B, and condenses it to the point b on the surface T. The light from the point A that falls on the lens is also condensed and would be brought to a point or "focus" at a beyond the surface T, but on the- surface the light forms a patch of consider- able size. Suppose that the lens is thirty times the diameter of the pinhole its area is 900 times as large, and the light that falls upon it is 900 times as much as the light that passes through the hole. Such an enormous gain of light is worth so much that photo- graphers willingly put up with the very many imper- fections of lenses for the sake of it, and if to this gain there is added the superior definition that is possible, it will be seen that lenses are indispensable to the photographer. To take a Daguerreotype portrait with 6O BARNET BOOK Ob' PHOTOGRAPHY. a pinhole might have required several days if not weeks exposure of the plate and therefore would have been impossible, so that the gain in brightness of image is a great deal more than a mere convenience. It will be observed in figure i that both points of light, A and B produce images on the surface T, although they are at different distances from it, but in fig. 2, although the effect of the lens is to concentrate the light from both points to two other points, one of these is beyond the surface T. This is a disadvantage inherent in lenses. They have so many other imper- fections or "aberrations" that it is desirable to consider these separately. The reader should bear in mind that the one aim of opticians in perfecting lenses is to con- centrate as much light as possible from each point in the object to a corresponding point, or as small as possible a dot, in the image, and the image should be flat because the plates used in photography are flat. Spherical Aber fatten. The surfaces of lenses are always ground to spherical curves, and this fact makes it impossible for a single lens, such as that shown in figure 2, to bring to a point all the light that falls upon it from a point. If a pencil of light passes through a piece of glass with sloping sides it is bent or "refracted" towards the thicker part of the glass, and the greater the angle of inclination of the two sides the more is it refracted from its original path. In figure 3 it is clear that the two sides of the lens shown in section are inclined to each other at a continually increasing angle LENSES. 6l as they approach each other at the edges of the lens. The refracting effect of the lens increases from the centre outwards, and it increases to a greater extent than is necessary to bring the incident light to a point. The focus of the pencils of light that pass through the edges of the lens is nearer to the lens than the focus of the pencils that pass through its central part. In the figure two foci are shown, a and b, but of course, in fact, intermediate parts of the lens produce intermediate foci, and what should be a point in the image, is spread out into a line on the axis of the lens, and all along this line is surrounded with the light that either is coming to a focus or that has come to a focus and has spread out again. On a screen placed at b there would be a point of light surrounded by a halo, while at a, nearer the lens, the central focus or point is surrounded by a brighter or more condensed light, and the appearance is of a circular patch of light with a brighter boundary. This is positive spherical aberration. Negative spherical aberration is due to over correction, the focus of the light passing through the margins being furthest from the lens, and the appearances on a screen are of course reversed. Chromatic Aberration. When light is refracted, that is bent out of its original path by a single piece of glass, it is not refracted as a whole, but each constituent behaves as if none other were present. Ordinary white light or daylight is a mixture of many coloured lights as seen in the rainbow, and when refracted, the blue is bent more than the green, the green more than the yellow, and the yellow more than the red. So that using a single lens the focus of the blue light is nearer the lens than the focus of the red light and the others come in between. In figure 4 this is represented in an exaggerated degree to make it more distinct. It will be 62 BARNET BOOK OF PHOTOGRAPHY. observed that a screen placed at the focus of the blue light will show a reddish margin and if removed further from the lens the margin or halo will be bluish. These two aberrations, spherical and chromatic were the principal faults that opticians had to deal with, because they affect the whole of the image, even the very central parts. But in photography it is necessary to get an image of a very large size as compared Avith the focal length of the lens, and there are some faults that only begin to show themselves at a little distance from the centre of the image and increase as the distance from the centre is greater. These aberrations were, practically speaking, incurable until a few years ago, but as recent optical advances have provided kinds of glass by the use of which they may be eliminated, or nearly so, they have become of practical importance. They are astigmatism and curvature of field. Astigmatism and Curvature of Field. If a diagram of suitable size is made with a series of concentric circles and radial lines upon it, and the centre of it is arranged exactly opposite the centre of the lens, and in a line with the centre of the focussing screen, the screen and diagram being parallel, then if the lens suffers from astigmatism it will be found impossible to get the outer circles and the radial lines where they cross them simultaneouly focussed. Where this difficulty begins the astigmatism begins, and the greater the difference there is between the focal planes of the radial lines and the circles, the LENSES. 63 greater is the astigmatism. It will probably be found with any of the older types of lenses that neither is in focus at the same time that the centre of the diagram is, but that the screen must be racked in ; this is due to curvature of field, and the difference between the curva- ture of field for the circles and the radial lines is due tc astigmatism. In the older lenses a flatter field could only be obtained by the introduction of astigmatism, but now by the employment of the new glasses made at Jena, it is possible to practically eliminate astigmatism, and still keep the field flat. The Development of Photographic Lenses. When photo- graphy was first practised the best lenses available were those made for use as telescope objectives, and they had to be used with a small diaphragm to get good defi- Fig. 5. nition over a sufficient field. With the slow processes then in vogue a more rapid lens was much desired, and Voigtlander introduced a " portrait " lens constructed according to the results of the calculations of Professor Petzval. This portrait lens is still very largely used, and figure 5 will serve to show its general character and will be a guide to the putting of one together correctly if it has been taken to pieces for cleaning. A rapid lens such as this could not cover a sufficiently large field for landscape work, so that single lenses were still used for work in which rapidity was not of very great importance. Single lenses were improved, and other kinds of lenses were introduced from time to time, but it 64 BARNET BOOK OF PHOTOGRAPHY. was not till 1866 that the " rapid rectilinears " or " rapid aplanats," called later "rapid symmetricals," and by innumerable other names according to the fancies of the makers, were introduced. Probably no lens has been made in such large numbers as this. At about the same time, Dallmeyer introduced his portrait lens in which the position of the convex and concave elements of the back combination is reversed, the concave lens being outside, and this gives the photo- grapher the opportunity of screwing it back a little, and so introducing a measurable amount of spherical aber- ration which has the effect of modifying the otherwise exceedingly fine definition at the centre of the field, and giving a greater depth of definition. In 1881, Messrs. Abbe & Schott began a series of experiments in the manufacture of optical glasses, and they were so successful in making new and useful varieties, that an optical glass factory was eventually established at Jena, by Schott & Co. By the use of these newer glasses the limitations that had previously restricted opticians were removed, and it became possible to correct astigmatism and secure a flat field at the same time. Zeiss of Jena, towards the end of 1890, introduced his first series of " anastigmats." The "concentric" lens of Ross was introduced in 1892, a lens which probably remains unsurpassed for flatness of field and freedom from astigmatism ; but as spherical aberration is present to a notable degree, an aperture of about //22 is the largest that gives sharp definition. The " double anastigmat " of Goerz of Berlin was put on the market in 1893. Itisa symmetrical lens, and in this different from the Zeiss anastigmats that preceded it. It consists of two similar combinations, each of three lenses cemented together. The unsurpassed qualities of this lens stimu- lated other opticians to seek to rival it, and there LENSES. 65 appeared similar lenses with four and even five lenses in each combination, besides other lenses that are more or less a copy of the double anastigmat. One of the most notable of these is the " satz-anastigmat " of Zeiss, each combination consisting of four lenses cemented together and forming an excellent single lens. These combin- ations are interchangeable in the same mount so that with, for example, one mount and three lenses, six different focal lengths can be obtained, as the lenses may be used singly or any two together as a doublet. The "Cooke" lens is remarkable for the simple means by which the various corrections are made, consisting as it does of only three single lenses separated from each other. Obviously it must be used entire. These lenses do not cover so large a plate in proportion to their focal lengths as most of the other anastigmats, but perform excellently over the plates for which they are constructed. The "stigmatic" of Dallmeyer is the latest lens of general utility. It gives good definition to the margin of the circle of light that it transmits, reduction of aperture being necessary, when its full field is employed, to get equality of illumination rather than to improve the marginal definition. Its two combinations are different, and either may be used alone as a single lens, giving focal lengths of approximately one-and-a- half and twice the focal length of the whole lens. The "planar" of Zeiss introduced just as we write, is a symmetrical doublet characterized by a very large aperture, from //3'6 to//4 up to 10 inches in focal length, and a little smaller above that. It is therefore compar- able with portrait lenses. Although it is symmetrical, a single combination cannot with advantage be used alone as a single lens. Telephotographic lenses are subsequently referred to. 66 BARNET BOOK OF PHOTOGRAPHY. The one aim of opticians in improving photographic lenses has been to get good definition all over a com- paratively large flat surface without having to use small apertures. A denning power on the axis of the lens, that is, at the centre of the field, far exceeding what can be taken practical advantage of in ordinary photography, has long been possible. But until recently, the defining power always rapidly deteriorated as the distance from the centre was increased. But to judge of the quality of a lens, or to compare one lens with another, there are other matters that must be understood, and these we shall proceed to consider. Focal length, aperture and image angle are the chief details concerning lenses, granting that the aberrations referred to above are satisfactorily corrected. Focal length. The focal length or focal distance of a thin lens is the distance between it and the point to which it converges parallel rays. The rays of light are parallel when they issue from an object at an infinite distance. For ordinary practical purposes, any object that is not nearer than a thousand focal lengths of the lens may be regarded as at an infinite distance, that is the image of an object so far off, and the image of the sun or stars (which are situated at the nearest approach to an infinitely great distance that we know of) would if separ- ately focussed give an inappreciably small difference of position of the focussing screen. But no photographic lens is very thin. The measurement from the back surface of the lens to the screen, when focussed on a distant object, is called the "back focus," but this is of no use whatever except as to the determining of the camera length necessary. The "equivalent focal length" is the focal length (or focal distance) of a thin lens that would give the same effect, so far as focal length is concerned, as the lens in question. When the simple LENSES. 67 expression "focal length" is used, it always refers to the equivalent focal length. The single word "focus" is sometimes used erroneously instead of "focal length." The focal length of all lenses (except to a very small extent, with single or so-called "landscape" lenses) is pro- portional to the linear dimension of the image that it gives under similar conditions. For example, a lens of 6 inches focal length will give just the same amount of subject on a quarter plate that a lens of 12 inches focal length will give on a whole plate, because the linear measurement of the whole plate is exactly double that of the quarter plate. The easiest way to compare the focal lengths of two lenses, is to focus both on a fairly distant object or view, and to measure in the image the distance between two fixed points in both cases. The proportion between these measurements is the proportion between the focal lengths of the lenses. By this method the focal length of any lens can easily be determined if one has a lens of known focal length. If a lens is first focussed on a distant object, and the focussing screen is then moved back until the image of any object is of the same size as the object, the distance travelled by the focussing screen is exactly the focal length of the lens. It is however exceedingly difficult to get at the same time an image of an exactly predetermined size, and to secure the very best definition, so that it is more convenient to get the image as near as it happens to come to the size of the object and then to allow for the difference, as then nothing interferes with the operation of focussing. The best near object to use is an accurately divided scale, and the details wanted in addition to those mentioned above are the comparative lengths of the image and the object. To get these, two fine marks are made on the focussing 68 BARNET BOOK OF PHOTOGRAPHY. screen, and the distance between these is the length of the image. The scale is focussed with critical exact- ness and so that it falls over these marks, then the amount of the scale represented between the marks can be measured, and the divisions counted for the length of the object. The distance over which the focussing screen was moved between the two focussings is to be multiplied by the length of the object and divided by the length of the image, and the result is the focal length of the lens. Aperture. The "aperture" of a lens is the diameter of the cylinder of light that it can receive and transmit. If the diaphragm is in front of the lens, the hole in the diaphragm is the aperture, but if the diaphragm is behind a part of the lens, so that the incident light passes through a lens first, the hole in the diaphragm is not the "aperture," the "aperture" is larger because the lens condenses the light before it gets to the diaphragm. The aperture of any lens can be measured by focussing a distant object, then replacing the focussing screen by a sheet of cardboard with a pinhole in the middle of it. In a dark-room a light must be placed behind the pinhole, and a bit of ground glass held in front of the lens. A disc of light will be seen on the ground glass and the diameter of this is the diameter of the aperture, or simply, the "aperture," with the diaphragm employed. Rapidity. The rapidity of a lens depends almost wholly on its focal length and aperture. The thickness of the glass makes a little difference, and at every surface in contact with air there is loss by reflection, but these and analogous matters are of comparatively little import- ance, and as they are uncertain and cannot be determined it is customary to refer rapidity to the focal length and aperture only. The aperture found, that is, the diameter LENSES. 69 of the effective incident cylinder of parallel rays, should be divided into the focal length, and the diaphragm corresponding to the aperture should then be marked with a fractional expression indicating the proportion of aperture to focal length. Thus if the aperture is one eighth the focal length, it is marked //8, if a sixteenth //i6, and so on. All lenses with the same aperture as so marked may be regarded as of equal rapidity whatever their focal lengths may be. Now the more rapid a lens is the shorter the exposure that it is necessary to give for any subject, and the exposure required is proportional to the square of the figure in the expressions as given above. Namely 8 and 16 squared give 64 and 256 which are as one to four, the proportional exposures required. Or we may say that 8 to 16 are as i to 2 and square these and get i to 4 the proportional exposures. The best way to mark stops is, for example, f/8 and //i6, as- these expressions are universally understood, but some persons think that the relative rapidities or intensities are better, others prefer to express the relative exposure necessary, and every system of numbering on these plans has a unit which is merely empirical, not one of them adopting the only true or scientific unit of //i. Zeiss has recently changed his unit from//ioo to f/$o. Dallmeyer marks some of his lenses now with the practical expression. The following table may be of service to those who happen to have lenses with their diaphragms marked on any of these empirical systems. BARNET BOOK OF PHOTOGRAPHY. fl B i 3 1 ti I 10 2 I fl 11 1 Paris Co 1 % N CU t/D ft 1 1 Paris Co N N 3.6 i ft 18 32 8 32 1024 2 5 6 20 4 o 4 4 i 22 36 50 5 5 2 '5 i 22-6 32 45 512 128 2 5 16 4 5 66 2 2736 75 7-5 | 6-3 4 tfe 256 6 4 31 62 loo | 10 707 5 i 32 64 4 36 1 8 2 866 7'5 1 387 150 15 9 128 32 44-72 200 20 10 10 I 45-2 128 11-3 8 50. 250 25 4 I 1225 15 I'5 5477 ! 300 30 12-5 64 16 63^5 ! 4 oo 4 14-14 20 2 64 256 15 Si 25 2 '5 70-71 506 50 16 16 71 2 17-32 3 3 100 I Angle. The image angle represents what is called covering power. It may be expressed in terms of the focal length, and doubtless this is the best method, but it is not customary. It may be expressed as an angle, the angle formed when a line is drawn from each extremity of a line equal to the diameter of the circle covered, and caused to meet at a point distant from the base line equal to the focal length of the lens. The angle where the two lines meet is the image angle. But generally the covering power is expressed more roughly, as the ordinary size of the plate that sufficiently good definition can be obtained on. Tele-Photographic Lenses. If a negative (or dis- persing or concave) lens is introduced between the ordinary lens and the plate, the equivalent focal length of the arrangement is greater than that of the ordinary lens alone, but the length of camera necessary is not LENSES. 71 proportionately great. It is possible therefore to obtain an image of a size that would otherwise require a lens of long focal length and a corresponding and perhaps impossible length of camera. But this is not the only advantage, for if the ordinary lens and the negative lens are separable to a variable extent, the amount of magnification of the image, or increase in the equivalent focal length of the optical system, is adjustable at will. For further details concerning tele-photographic lenses and their use, reference should be made to Mr. Dall- meyer's pamphlet on the subject. There are two other subjects connected with the production of images by photographic lenses that must be referred to, though neither of them is of great importance if we exclude the use of hand cameras (which are separately treated of) and bear in mind the ordinary practice of to-day. These are depth of defini- tion and the distortion due to the use of single lenses. Depth of Definition. It has already been shown that the action of the lens is to bring to a point in the image all the light that falls upon it from the corresponding point of the object. Now it is clear from fig. 2 that, if different parts of the object are at different distances from the lens, and this must be the case with solid objects, , these different parts cannot be in focus at the same time. Still it is possible to get them so nearly in focus that the result is serviceable, and the ordinary method of doing this is to examine the image on the ground glass, and if the whole subject is not sharp enough, to reduce the size of the aperture. Depth of definition is increased by using a lens of shorter focal length or by reducing the aperture. If a large aperture has to be used, the focal length must be short if much depth of definition is wanted, or conversely, if the focal length must be long the aperture must be small. It 72 BARNET BOOK OF PHOTOGRAPHY. follows that very rapid lenses that have a very lon<^ focus are of no use, for in portraiture, for example, this combination of properties would lead to the ear in the image being fuzzy if the eye was sharp. If a lens were perfect and had a flat field, the depth of definition would depend only on the aperture and focal length. But if the lens gives inferior definition towards the edges of the field, it is quite obvious that there must be less depth of definition there, if a minimum of defining power is accepted. The definition at its best may be inferior to the minimum accepted and then obviously there is no depth. Depth of definition therefore at the centre of the plate depends entirely on the focal length and aperture, but away from the centre it depends also on the quality of the lens, and is much greater in a flat field anastigmat than in a lens of an older type. But depth of definition is not a quality apart, it depends entirely upon other factors, and it is better in examining a lens to determine these factors separately rather than to lump them together as depth. Distortion produced by single lenses is due to the fa 61 that the diaphragm is either in front of or behind them. If the diaphragm is in front, the image is drawn towards the centre of the plate to an extent that increases as the margin of the field is approached. A line along one side of the plate has its ends drawn in to a greater amount than its centre, because they are further from the middle of the plate, and therefore it becomes curved like the side of a barrel, and this effect is called barrel-shaped distortion. If the diaphragm is behind the lens, the displacement is outwards, also increasing towards the edges of the field, and a straight line at the edge of the plate becomes curved so that it is convex towards the centre of the plate. This is known as hour-glass distor- tion. Both these effects are illustrated (and exaggerated MELTON MEADOWS. A. HORSLEY HINTON. LENSES. 73 for clearness' sake) in fig. 6, the central square repre- senting the true figure. This "curvilinear distortion" is absent in all cases in the middle of the plate and gener- ally for a considerable area, and if single lenses of only long focal length are used, say of a focal length equal to at least one and a half times the length of the largest side of the plate, it may be neglected. Wide-angle single lenses should never be used except on a suitably small plate, so that the above conditions hold. The nearer the diaphragm is to the lens the less is the distortion, and some of the most modern single lenses have the diaphragm so near that the photographer is even more safe in the use of them. The Comparison and Use of Lenses. The optician when he tests lenses looks for each fault individually, but this the ordinary photographer is hardly able to do, nor is it particularly desirable for him, because if a lens is inferior it matters little to him why it is so. On the other hand occasion may arise when he wants to identify a fault, then the information already given will probably be sufficient to enable him to do so, if to it is added that a small pinhole with a flame behind it is a convenient point of light, and that if the image of this luminous point is examined with a good eyepiece, without the focussing screen, at various parts of the field, the character of the defect may be discovered. The main things that the photographer needs to look to in judging of a lens or comparing it with another, are (i) that it works to focus, (2) the quality of its defining power especially towards the edges of the plate. There must also be taken into account the focal length and aperture, and if both these are not the same in the lenses to be compared they should be nearly the same, and the proportion that the aperture bears to the focal length should be exactly the same. A special diaphragm 74 BARNET BOOK OF PHOTOGRAPHY. may have to be cut out of card for one of them. The best test object that is always at hand is a newspaper pinned flat against a flat wall. The camera must not be moved during the work. Each lens is very carefully focussed and a negative made, using the same aperture, time of development, and in all ways similar treatment for both. If the focal lengths are different, the images will be of correspondingly different sizes, and then the same detail must be compared, not the definition at the same distance from the centre. All good lenses work to focus, but some of the cheaper ones do not. To test this, any series of small objects arranged side by side, but at distances varying by intervals of say two inches from the camera, is photo- graphed after carefully focussing on the middle one. I f any other than the middle one is the best defined, the lens is at fault. But in this, as in all similar tests, it must be remembered that ordinary dry plates are not quite flat, and the error of the plate may make an appreciable difference. The use of lenses comprises the whole art of working with the camera, it is therefore not our province to say much about it. But so far as lenses themselves are concerned it may be remarked that, if a lens has a round field, it may be advantageous to tip up the lens with regard to the plate when only a part of the plate is being used, as for example sometimes in taking a landscape. But in using the modern flat field lenses special care should be taken to keep the lens and plate exactly true to each other, the plate exactly at right angles to the lens axis. The image and plate must coincide or defini- tion will suffer. If the image is rounded and the plate flat, then in any case the result is only a compromise* but to take full advantage of the larger apertures when the field is flat, much more care than has been usual must be devoted to this matter. LENSES. 75 Simple uncorrected lenses such as spectacle lenses or " monocles,'" suffer from the defects that have already been described, and are valued on this account by some workers because they give blurred or " soft " images. With a small enough diaphragm they will give good definition, and generally it may be stated that reducing the aperture lessens the effect of any fault that a lens may possess. To get the best definition that a simple lens will give, the plate must be brought nearer the lens after focussing by about one-fiftieth of the focal length of the lens, so that it may be brought from the best focus of visual light into the best focus of the photographically active light. If the object photographed is nearer to the lens than about one hundred times its focal length, the amount of movement after focussing must be increased. If four focal lengths distant, the correction is nearly one-thirtieth of the focal length, at three focal lengths distant, nearly one-twentieth, and at two focal lengths, about a thirteenth. Pinlinles give an image that for all practical purposes may be said to be equally blurred or " soft " over the whole plate. Much has been written about pinholes and their use, but it is not definitely known yet whether the exposure should be longer or shorter than the exposure required when a lens is used, allowing, of course, for the smallness of the aperture. The following short table and exposure rules from the writer's " Science and Practice of Photography," will probably prove useful: Pinholes diameters .... A A & A Distance from plate for 1 sharpest image . . . . ' 64 32 16 8 4 All the above figures are in inches. Whatever pinhole and at whatever distance, estimate the exposure for a lens 76 BARNET BOOK OF PHOTOGRAPHY. at //i6, //22, 7/32, 7/45, or 7/64, as the case may be, and multiply it by the square of the number of inches that the plate is distant from the pinhole. But if the distance is as given above for any hole, it is sufficient to expose for as many minutes as the plate is inches distant from the hole, for a subject that would require one second with an aperture of//i6. Chapman Jones. 77 Portraiture. E photographer who may be expert at landscape or architectural work, will find himself at a loss when he essays portraiture. For apart from the art of managing the sitter (a most important element in producing a successful result), he will soon find that the kind of plate that is suitable for outdoor work does not answer well for portraits, unless the developer is greatly modified, for quite a different kind of negative is required. As a general rule it is advisable to use very rapid plates for por- trait work ; and in this respect, at the present day we are much better supplied than even five or six years ago, and with an extra-rapid plate it is possible to secure a fully exposed negative in half a second, in weather and under lighting that was quite impossible ten years ago. 78 BARNET BOOK OF PHOTOGRAPHY. The best expression and pose are generally secured when the sitter is unaware of the actual moment of exposure ; and for this purpose a silent shutter working inside the camera is best. The sitter should never be asked to keep still unless, in groups, and when circum- stances necessitate a long exposure ; and nowadays an exposure of five or six seconds is a long one. Every effort should be made to put the sitter quite at ease. A head-rest should not be used unless absolutely necessary, and few photographers are aware how easily it can be dispensed with, and fail to realize how strong an objection nearly every sitter has to it. It is far better to have an occasional plate spoilt by working without the rest than to make every sitter uncomfortable by its u;;e. I n fact some portrait negatives are actually improved by a slight movement. In a special kind of lighting when the face is in shadow relieved against a light background. a slight movement which produces the effect: of diffusion of focus greatly improves the result. Great care must be exercised in choosing the back- ground even when it is only plain or graduated, and it is well worth exposing three or four plates on the same sitter, in the same position and lighting, and with the same exposure, but with different backgrounds, and then carefully comparing the resulting prints. Even if only one background is at hand its depth can be varied by placing it nearer or farther from the source of light. The background must also be selected to suit the lighting of the sitter, as a background of medium tint suitable for what is called " ordinary lighting " would be quite unsuitable for " Rembrandt " effects, or where strong contrasts of light and shade are used, when part of the face is in dark shadow. For such effects a dark background is usually best, as it gives luminosity to the shadow side of the face. "But such dark grounds are PORTRAITURE. 79 not suitable for " ordinary lighting " where the face should be full of delicate half-tone, all of which would be killed by the strength of the dark background. For the Rembrandt effects a much longer exposure is necessary as less light is reflected from the face on to the sensitive plate ; they will often need twice or three times as much as for ordinary portraits. When pictorial backgrounds or accessories are used it must be remembered that the object of the photograph is to secure a portrait of the sitter, not to show what a large stock of accessories the photographer possesses. It is best to use as few accessories as possible ; I have heard a lady complain bitterly of a well-known photo- grapher, who having posed her in a very difficult position, kept her waiting for five minutes while he arranged a screen, a palm, a footstool, a tiger-skin, etc., so that she felt positively ill before the exposure was made. The sitter should not be kept waiting in the pose to be photo- graphed any longer than is absolutely necessary. If accessories must be used they should be simple and suitable. When portraits have to be taken in ordinary rooms it is advisable to get a friend or assistant to experiment upon, if possible beforehand. Even a few minutes spent in studying the possibilities of light and arrangement of furniture will save a great deal of worry when making the actual exposures, and nothing upsets nervous sitters more than having all kinds of experiments and arrangements made with them. But it is sometimes well worth wasting a few plates on exposures which the photographer thinks will be useless, in order to give the sitter time to get accustomed to the room ; it must not be done in a fussy, irritating way, but rather to show that it is not such a very dreadful operation and really "doesn't hurt." This plan often works well with 80 BARNET BOOK OF PHOTOGRAPHY. nervous children, who soon become accustomed to the room and the photographer. There is a great deal to be said in favour of the maxim " leave your sitters alone." The photographer must cultivate quick observation so that he sees at once a good pose, and secures it ; and here again quick plates are essential, as many of the most charming poses are caught unexpectedly. It has been well said that the best poses the photographer secures are those he observes, not those he creates. But a spontaneous pose may not be quite perfect and a slight alteration may be easily made without disturbing the rest of the figure. It will generally be found that a pose that takes a great deal of arranging is not a success. When taking portraits in an ordinary room it is usual to place the sitter near the window, so that one side of the face is strongly lighted and the other in deep shadow, and then use a white reflector to light up the shadow side. It is often better, when the window is a large one, to place the sitter farther back in the room almost facing the window, and put the camera near the middle of the window looking into the room ; a softer lighting will then be secured. For outdoor portraits a shady corner is best, and if possible, one where the side light is much subdued on one side ; a light head-shade may be used with advantage. A large grey rug out of focus makes a good background ; a blanket is too light. A portrait lens is best for the work; but if the photographer does not possess one, he need not despair of producing good work. A rapid rectilinear lens used . at a large aperture will answer the purpose well ; it should always be used at full aperture, partly for the sake of quickness in exposure, and partly to prevent accessories and parts of the dress appearing too sharp and competing in importance with the face. Subordina- tion of parts is one of the essentials of a picture ; and if PORTRAITURE. 8l we examine a good portrait we shall find that probably no part of the photograph is quite sharp except the eyes and face. Otherwise the less important details are apt to obtrude themselves on our notice. A stop will generally be necessary, however, with a portrait lens if a full or three-quarter length is to be taken, and it will be found that heads only (as a rule) can be taken at full aperture. Just as good work, however, can be done with a rapid rectilinear as with a lens specially made for portraits, except where rapid exposures are to be made ; but it is necessary to use one of fairly long focus. A rapid rectilinear lens used for landscape work on a half plate would be much too short in focus for giving good portraits on the same sized plate, for in order to get the figure large enough it is necessary to place the camera so near the sitter as to produce distortion. For portraits on a half plate a lens of at least nine inches focus should be used and for a whole plate not less than sixteen or eighteen inches, and longer if possible. The swing back of the camera will be found useful in portrait work for getting parts of the figures into focus that are either too far behind or two far in front of the plane of the face. For instance, a full-length figure leaning back in a chair will have the feet out of focus when the face is sharp if the back of the camera is vertical, and this applies with even greater force to groups. A side swing too is useful, but is not absolutely necessary. Even in bust portraits the swing back is useful in getting the shoulders in focus when using a large aperture, for although it is well not to have the whole of the figure in perfect focus all over, it is not advisable to have the face sharp and the rest so out of focus as to be blurred. The development of a portrait plate should be different from that of a landscape, because a different 82 BARNET BOOK OF PHOTOGRAPHY. kind of negative is required. A rapid plate developed so as to give a soft delicate image is best ; and a developer containing more alkali and less density giver is good, and it may be considerably diluted with advantage. The image should appear within ten seconds of pouring on the developer, and the negative will generally be developed to sufficient density in from two to three minutes. With a good average rapid plate the image should show fairly well on the back of the plate, but this and the time of development will vary so much with different developers, and with the taste of each photo- grapher that no hard and fast rule can be laid down. Developers that give a brown deposit, or that stain the film will require shorter development than those of the newer developing agents that give a cold black colour to the negative ; another fact to be borne in mind is that the image formed by these latter appears to lose more density in fixing than when pyrogallic acid is used. A perfect portrait negative should have no clear glass shadows, and no part should be so dense as to give white in the finished print, and some negatives which give the best results may have a decided veiled appear- ance in the shadows. The temperature of the developer is another important point, in very cold weather the developer should be kept warm, or if in concentrated solutions may be diluted with warm water. In cases of known under- exposure the developer may be used quite hot with advantage. A convincing experiment can be made by cutting an exposed plate in two and developing one half with icy cold developer and the other half with warm. The difference is really remarkable. If the developer has been used hot enough to make the gelatine of the plate feel "slimy" an alum bath is necessary, unless the fixing bath contains chrome alum. PORTRAIT URK. 83 METOL. Wa:cr ion parts or 10 ozs Metol i part or 50 grains Sodium sulphite 10 parts or i oz. f 2. Water 100 parts or 10 ozs. Potassium carbonate .... 10 parts or i oz. 3- Potassium bromide i part or i oz. Wa:er 10 parts or 10 ozs. For normal exposures take 3 parts No. i and i part No. 2; to each ounce of mixed developer add 40 minims of No. 3. PYRO AND SODA. i. Pyro i oz. Water 70 ozs. Nitric acid 12 drops Sodium sulphite 10 ozs. Sodium carbonate (pure) 8 ozs. Water ... 70 ozs. Bqual parts of each, for soft negatives dilute with water. To restrain for over-exposure use potassium, not ammonium bromide. Unless an acid fixing bath is used the negatives are rather green in colour. RODINAL AND HYDROKINONE. A. Sodium sulphite i oz. Water 20 ozs. Citric acid i crystal Potassium bromide i dram Hydrokinone 2 drams B. Potassium carbonate 2 ozs. Water 20 ozs. Rodinal i fluid oz. Use i part A, i part B, and i part of water. The question of retouching is a difficult one. There Is no doubt that a certain amount of it is necessary on nearly all portrait negatives and even on those of 84 BARNET BOOK OP PHOTOGRAPHY. children. But it is equally certain that the great majority of portrait negatives are over-retouched, so much so that their value both as portraits and pictures is nearly destroyed. Yet a certain amount is necessary even for pictorial effect, and perhaps still more when the question of likeness is considered. For as a rule the untouched negative is no more a true likeness than the over-retouched one. The truth lies somewhere between the two. Even if isochromatic plates are used the little differences of colour in the face, and the incipient wrinkles are exaggerated in an unpleasant way. Under-exposed negatives will show these defects in a very marked manner, full exposure will greatly reduce them. Large heavy patches of shadow may be lightened by coating the back of the negative with matt varnish, and when it is quite hard " hatching " upon it with a soft lead. Harsh lights may be reduced by scraping away the matt varnish with the point of a knife. In some cases the matt varnish may be stained with a little aurine or uranine. Exaggerated lines and small shadows must be worked upon from the front and a retouching desk is necessary. The film of the negative will not take the pencil without some preparation. The best surface is obtained by spreading a little retouching medium with the tip of the finger on the part to be touched. A thin film of soft resin is left upon the plate which takes pencil marks readily. A hard lead, No. 4 Faber or Hardtmuth, should be used. The loose leads used in what are called the " ever-pointed holders " are most convenient. The point must be very long and fine, like a large darning needle, and is best made by rubbing the lead on a piece of fine glass-paper. The pencil must be held very lightly and the lines touched away with short light strokes, a heavy stroke only rubs the medium up. PORTRAITURE. 85 The little shadow at the end of the mouth often has to be reduced, often at the risk of spoiling the shape of the lips, but sitters will insist upon it being done, and say " You have made my mouth much too large." Freckled faces are perhaps the most difficult to retouch, as it is well nigh impossible to remove the black patches caused by the freckles without at the same time destroying the modelling of the face. Yet it must be done, for probably the most severe stickler for truth would not insist on the black blotches that freckles produce in a photograph. A great deal can be done to improve a hard negative as soon as it leaves the fixing bath, by applying a mixture of hypo solution and a solution of ferricyanide (not ferro) of potash with a piece of cotton wool to the dense parts. The proportions for this reducing bath are as follows : To each ounce of the ordinary hyposulphite of soda fixing bath add a few drops of a 10% solution of ferri- cyanide of potassium or red prussiate of potash, making the whole about the colour of pale brandy. By adding more of the ferricyanide solution the reducing action is quicker, but there is a greater liability to stain the film. The work should be done over a sink with a tap of running water at hand. The solution should be of a deep lemon colour (it is almost impossible to give exact quantities), and after a short application must be washed off under the tap, and the negative may then be examined, and the reducer applied again and again till the desired reduction is obtained. It is advisable to make a few trials on spoilt plates. For if any really good work is to be done there will be plenty of rejected negatives. Probably, of all the plates exposed on portraits by first-rate professional photographers, not more than one-fourth ever get as far as the printing- frame. 86 BARNET BOOK OF PHOTOGRAPHY. Moral : Do not be chary of exposing plates, they are cheap enough now. Don't feel, " Oh ! this will be good enough. I won't do another." On the other hand don't expose carelessly and recklessly and say, " It will all come right in developing." Good work is not done that way. Use every opportunity of seeing good work. Study the work of great portrait painters, but don't neglect the photographers. Go to all the exhibitions of pictures and photographs within reach. Don't be satisfied with what you have done, but make a resolve to do something better next time. Remember, what is worth doing at all is worth doing well. Harold Baker. OS Boulogne. By A. Horsley Hinton. Pictorial Photography. NLIKE the subjects of the other articles in this book, in pictorial photography we are not brought to consider one of the many processes which go to make up the photo- graphic craft, but merely a special and exceptional application of any and all means known to the photo- grapher. The particular end to which this application is made will be explained as far as the limits of space will permit, and some of the methods of such appli- cation will be described. Beyond this I have no intention of going. I do not present pictorial photo- graphy as a branch of photography especially worthy of study I am not concerned in making converts. It is for the photographer who has already formed a desire 88 BARNET BOOK OF PHOTOGRAPHY. to give his attention to the pictorial side of photography and who is seeking help, that this chapter is designed. First let us come to a mutual understanding as to the term Pictorial Photography. Picture-making by photography would perhaps be a simpler phrase, but that to my mind the word " picture-making " is too similar in idea to boot-making, lace-making, etc., all of which imply a mechanical manufacturing, whereas a picture a real picture like a musical composition, a poem or a beautiful thought, grows or is evolved rather than made to order. Art photography would be a better term, but that in photography the word " art " has been so often coupled with things the very antithesis of artistic and might hence be misleading, moreover the photographer will show discretion rather than weakness if he be not too hasty to claim for photography a position among the arts, and whilst its claims to that dignity remain as yet in dispute, we may be content with "Pictorial Photography" as a less assuming title, yet one which will sufficiently differentiate between what we may call the ordinary photographic production and - Well, what ? That is the first thing I have to try and explain. Look at the illustrations in this book on pages 72, 136, and 120, and, making due allowance for some loss of quality due to reproduction by a "half-tone" block, try to imagine what the originals were like. Then say if they please you. If you say no, you do not care for them, they do not appeal to you, you do not mind if you never saw anything of the kind again from this day henceforth ; very well, doubtless there are other things in the world in which you can find pleasure, but so far as my present subject is concerned, here you and I part company. These illustrations are more or less success- ful reproductions of pictorial work, and if you do not like MISS LILY HANBURY A PORTRAIT. HAROLD BAKER. PICTORIAL PHOTOGRAPHY. 89 them, making as I have said due allowance for their being reproduced and reduced, then it is certain you do not want to hear anything about them, and it is not my intention to persuade you, so please pass on and make room for those who do care for these things and wish to learn all they can concerning them, or at most stand aside and peradventure some stray word dropped unin- tentionally may quicken your interest and discover in you a sympathy of which you were previously un- conscious. Referring now again to the illustrations which in the absence of anything else we take as fairly typical of pictorial photographs and assuming that one or the other, if not all, do please some of my readers, I will ask then! to endeavour to analyse their feelings when confronting such productions. Take now an ordinary commercial photographic view such as one may purchase from any seaside stationer, and compare the sensations awakened by each. In the case of the topographical view we feel some satisfaction at being able to recognise a familiar spot, or the view reminds us of some other place, or it may be quaint buildings, or rugged mountains, or miles of foliage, or what not inspire curiosity or interest because we know the photograph to be a true record of facts, that is to say we accept the photograph in lieu of the actual presence of the objects represented, and experience nearly the same feelings as we should were we to visit the spot represented. We know that the wonderful, curious, or unusual things portrayed have an existence, otherwise we could not have a photograph of them. In all such cases our interest and value of the photograph would vastly diminish, were it possible for a photograph of this kind to be made simply by the photo- grapher's hand and imagination without any original at all. go BARNET BOOK OF PHOTOGRAPHY. You look at a photograph of this or that sea-side place and remark, " Ah, yes, that's dear old Yarmouth, many a time, etc., etc.," or else, " Dear me, I wonder what place that is, it's so like " such and such a town, or it may be you enquire " Where's that ?" and you express or think to yourself you would like to go and visit the spot. These and kindred sensations are those kindled by the average photograph, but there is yet another, for you may be impelled to exclaim, " How wonderfully clear and bright that photograph is," " What a good photograph." In this case you are interested purely in the execution as an example of clever manipulation and skilful craftsmanship. Now, compare such feelings as these with those stirred by an example of good pictorial work. In the first place your esteem for it, if you value it at all, is quite as gr.eat whether you know the place where it was made or not. If it pleases you, that pleasure is not dependent upon the fact that it does represent some place. In the case of paintings and drawings as often as not they do not pretend to represent any place at all, but are pure fiction, yet we do not value them the less. To what then is the pleasure we feel when looking at a good picture due ? Is it not that a picture stirs up, that is, creates pleasant or beautiful thoughts and ideas by pleasant I do not mean necessarily merry or joyous ones, for some hearts feel profounder pleasure in the grandeur of storm or the majesty of the mountain than in the sweet wilderness of flowery wastes, but notice that such beautiful ideas are created by the picture. You were thinking of something totally different before you came upon the landscape picture which instantly made -you feel the glowing light, the stirring breeze, and hear the rustling corn and noisy brook, and yet it cannot be said it is because we recognise these things in the PICTORIAL PHOTOGRAPHY. gl picture that we receive these impressions, at least it is not the kind of recognition which takes place when we see a photograph of Brighton Pier or Haddon Hall. Notice, it is not the exact and faithful portrayal of objects that creates the emotions instanced, for if you closely observe the manner in which a good painting is done you will find that rude splashes of paint, broad brush strokes, and the like stand for foliage or water, or corn stalks as the case may be, when we know that had the painter desired he could have produced his likeness of nature with a good deal more of the precise detail and fidelity to outlines which photography excels in, had he wished. But if the painter or other pictorial artist needs not to trouble about accuracy to details to secure the effect aimed at he must be faithful to general facts. There is a great difference between not recognising things or having no particular wish to do so, and feeling conscious that a portrayal is so utterly unlike anything in our past experience of nature that we should not recognise the objects even if we were acquainted with them. To take an extreme case our enjoyment of the effect and sentiment of a beautiful landscape picture is not enhanced by our being able to recognise whether the trees afe oaks or elms, but it would be distinctly dis- turbed if the palm trees were represented as growing on the slopes of a Welsh mountain. Innumerable examples and instances might be given to show that the artist, whatsoever his medium, be it colour or monochrome, may depart from truth, or may be indifferent to precise details, only so far as he avoids palpable untruth. Why is this ? When we look at a powerful and impressive picture we feel at once the sentiment, our emotions are at once stirred, subsequently we recognise objects and facts portrayed, but only when we begin to look for them or 92 BARNET BOOK OF PHOTOGRAPHY. think about them ; but a gross exaggeration or a very obvious error strikes us at once before we begin to receive sentiments and ideas, and that error or exaggera- tion once seen is never lost sight of, and whole enjoy- ment of the picture is hopelessly marred. Now, from the foregoing (for want of space I am aware that the argument is incomplete, and must there- fore ask the student to think the matter out and grasp the side issues by reading between the lines) we may formulate the broad definition that a picture does not depend for its excellence on the faithful representation of objects, and is not chiefly valuable on account of our immediate recognition of things portrayed, yet on the other hand it must not let us feel that there is obvious inaccuracy. Here then we have two opposite positions in both of which the mere objects employed to build up the picture are subordinated to the effect or impression of the picture. In one case the spectator must not be allowed to feel that the representation is wrong, in the other success will not directly depend on the representation being very right, neither startling Tightness or truth nor the obvious wrongness or untruth should thrust the objects composing the picture upon the beholder's attention, he should be left free to receive the expression or sentiment of it. I hope the reader is following me in this line of thought closely. I am aware that it may seem dry and uninteresting, but I see no other way of placing the student in a proper position at the outset than by explaining the essential elements of pictorial work, and I will make this introductory part as brief as possible. Reverting now to our argument, I have in other words suggested that obvious violation of truth will prevent the sentiment or effect of the picture from being PICTORIAL PHOTOGRAPHY. 9^ paramount, and now I will submit that an excess of accuracy to detail is equally detrimental to the success of a picture as a picture. If by now the reader is prepared to admit that the chief purpose of a picture is the feelings, emotions, ideas which h. suggests or creates, and not the facts it portrays, he will be able to go further and perceive that in a land- scape, for instance, cottages, trees, or what not are intro- duced, not for their own intrinsic interest but as vehicles of light and shade, which go to express the picture's sentiments. If we stand before a good picture with closed eyes and suddenly open them, our first impression (precluding any question of colour) is that of masses of light and shade pleasingly and harmoniously arranged; if we retreat to such a distance that the objects constituting those lights and shades are unrecognisable the balance and pleasing arrangement should still be felt, and our aesthetic sense is satisfied, although we do not see fully of what the picture is composed. This is the quality which is termed breadth and which is admittedly of very great value. If on the other hand the shadow masses are filled with innumerable details, and are thus broken up into tiny lights and shadows they no longer exist as broad masses of dark, but if before retreating as proposed from the picture, the lights or shadows appear so blank as to prompt particular investigation, and upon examination we find detail absent which we know must have been present, then we encounter an instance of untruth and exaggeration which is obvious and which disturbs our appreciation of other fine qualities. Thus we require sufficient detail to avoid giving the idea that detail is left out. The delineation of sharp outlines and redundance of detail is not wrong in itself, but it is usually inexpedient 94 BARNET BOOK OF PHOTOGRAPHY. when considered with respect to the effect to be pro- duced, similarly the suppression of sharp focus both as regards outlines and details has no artistic merit of itself except as it assists the picture to impress the beholder first with the general effect. The painter and photographer start from two opposite standpoints. The painter, or draughtsman, starts with nothing but blank paper, and having built up his picture and produced his desired effect he elaborates no further ; the photographer with his more or less mechanically produced facsimile starts from the opposite extreme with a transcendentally elaborate image, from which he will require to eliminate all such excess of truth as is likely to force the mere facts of the view upon the beholder's attention. Photography, so faultlessly complete in its delinea- tion, gives us more than the pictorial worker needs for the expression of an idea, and this is why I would remind the student that pictorial photography is not photography in the full sense of the word, but the application of some of its powers, just as much as we need and no more, to a definite end. As just hinted the purpose of a picture is to express ideas, hence 1 will fall back on a kind of definition which I have used on a previous occasion that a picture is the portrayal of visible concrete things for the expres- sion of abstract ideas. To give an example by way of exposition we may look upon a picture and be made to feel by it the calm and luminous atmosphere of evening ; we feel at once the restfulness, and almost feel the warmth of the humid air, giving place to the chill gathering mists of night ; but the same objects, the same tangible materials, paper, pigment, metallic salts, etc., in another picture give us the sense of angry turbulent storm or perhaps PICTORIAL PHOTOGRAPHY. 95 bright joyous sunshine frolicing with the fresh breezes on the hill-tops. These are abstract ideas expressed or created by the manner in which concrete things, commonplace facts, are portrayed and rendered. Finally, let me enunciate that a very excellent photograph may not necessarily be a good picture, because it may contain more than is required for the expression of its idea, and the surplus will overwhelm it ; again, a good pictorial photograph may be but a poor photograph, because if we claim the right to apply photographic means to pictorial ends, we may find it convenient to leave out the very qualities which the scientific or technical expert considers most precious. And now I think we may proceed to more practical matters. COMPOSITION AND SELECTION. In all matters frcru which the eye expects to derive pleasure, symmetry of design seems essential. In the formation of the letters that we write, in personal attire, in the decoration of our homes, in buildings, and practi- cally in everything which is not of a purely utilitarian character, a sense of proportion and a symmetrical dis- position of parts is observed. Hence it is no source of surprise that in a picture which as much as anything should aim at. pleasing the eye, design, otherwise Composition, is with Expression a co-essential. In a purely decorative production this natural desire of design is the only thing to be observed, but in a picture which may be decorative, but must be something more, we have expression as well to consider If decoration alone were to be regarded, something like fixed rules might perhaps be tyrannically laid down, but in a picture the implicit observance of rules of composi- tion would be certain to make itself seen in the result, 96 BARNET BOOK OF PHOTOGRAPHY. and the undue obtrusiveness of a code of rules would be as inimical to the supremacy of ideas and feelings, as the excessive prominence of fact would be, which has already been described. Hence the difficulty in prescribing any definite course for the beginner, because whilst to most in- stinctive artistic temperaments a certain knowledge of or feeling for composition is natural, so soon as this is reduced to definite rule and given to another, the, as it were, secondhand use, is nearly certain to betray itself by its misapplication. I would ask therefore that any sug- gestions given here on the subject of composition should be taken as one takes lessons in the rudiments of a language, which rudiments we violate and forget so soon as we have become proficient enough to speak it. Such rules in composition should be. observed only so far as to avoid the appearance of having infringed or ignored them. The rules of composition which may be found to apply in one of the pictorial arts must necessarily apply equally in the others, and so therefore to pictorial photo- graphy which at least aspires to be considered an art. If on a sheet of paper a rectangular space is given us wherein to draw the likeness of anything, the most natural course to pursue would be to draw that figure in the centre or thereabouts, and if then we are asked to add the likeness of two or three more objects we should naturally place these near the first object. Thus should we compose a group of objects which draw the attention to the middle of the picture or space. Suppose we are asked to draw the picture of a church tower we should probably comply with the request somewhat as shown in fig. i. Next we will suppose we are asked to add a cottage, some trees, and a path to the church, we should, if possessed of some sense of symmetry and order, coupled with average PICTORIAL PHOTOGRAPHY. 97 intelligence, make the additions somewhat as in fig. 2. It would surely be an unusual thing to follow instead the course suggested by figs. 3 and 4. In figs, i and 2 we have instinctively placed the primary object in or near the centre, and the others near I r. a. and around it, and the result strikes one at once as being better composed, that is, more svmmetrical, than in fig. 4, in which amongst other things one is not sure which object to regard as the principal one, and one also feels that but for the boundaries of the picture left and right we might have seen a good deal more beyond, which would have added to the interest of the picture. ! nnW, In! In this we have one of the first rules in composition, namely, that the principal object should be near the centre, and the next important near to, and as it were supporting it, and no object likely to attract the eye should be so near the edge of the picture as to make us instantly conscious of the boundaries and wish to se more beyond. 9 8 BARXET BOOK OF PHOTOGRAPHY. But no\v if in compliance with the supposed request we had made our drawing as in fig. 5, might it not at once be felt by the observer that we had put the objects in a central position intentionally, which is equivalent to saying that we had allowed our endeavour to observe the rule just laid down to betray itself. Fig. 2 is preferable as being only just sufficiently symmetrical to avoid being unsymmetrical, which is an example of what has already > ^ Fig. 5- Fig- 6. been said about the necessity of observing rules of com- position just so far as to escape the appearance of having broken them. If this rule is right as regards voluntarily drawing a picture, it is equally so in the case of a photograph, but instead of deliberately placing things in such and such positions, we attain the same end by moving the camera and selecting our point of view so that the objects come into the positions desired. Now suppose then, we have done this, but in doing it we are quite unable to prevent other objects coming into the field of view and occupying undesirable places near the margins of the picture, as for instance in fig. 6. Here we are brought to consider another rule or prin- ciple in composition, namely, that there must be one and PICTORIAL PHOTOGRAPHY. 99 only one chief object in the picture, whereas in fig. 6, apart from the gate and tree on the one side and the windmill on the other attracting attention to the margins of the picture, these same objects arrest the attention quite as much as the church, and we feel the eye wandering about from one to the other and missing the sensation of centralization and rest which fig. 2 gives. If we were drawing or painting we should put in what we want and then stop, we should omit or ignore what we did not require, but in photography our powers in this direction are limited, and hence we must as far as possible select those views, and only accept such, as comply with what we feel to be right. The angle of view included by different lenses is an auxiliary not to be neglected, for by substituting a narrower angle lens, that is, one of longer focus, we may cut off or leave out undesirable objects which the shorter focus lens might include. Then again, when the print is finished we can after careful consideration cut off what would have been better left out, for it will be better to have a picture half the size well composed, than double the number of inches with a distracting and unsatis- factory arrangement of objects, hence with many most successful workers it is no uncommon thing to take quite a small portion of a negative, and either print it as it is or else enlarge it up to the desired size, but mere size will reckon as nothing as compared with pleasing composition. If it is inexpedient to let the principal object or group of objects occupy the exact centre of the picture, measured from left to right, it is equally so if the centre be measured from top to bottom, and hence we may formulate the rule (to be broken perhaps later when we are strong enough to be independent of guiding) that the IOO BARNET BOOK OF PHOTOGRAPHY. horizon should not be allowed to come midway between the top and the base of the picture. Remembering now that, as set forth in the earlier part of this article, a picture should appeal to our feelings Fig 8. and stir our emotions, it may be pointed out that in most ordinary things, and certainly in the arts, the most PICTORIAL PHOTOGRAPHY. powerful things are those which possess one dominant idea or feature, as in a piece of music the refrain keeps recurring, a preacher takes a text, in a story there is one hero, and so forth, and in point of composition fig. 7 is better than fig. 8, although the view is less comprehensive. Fig. 9. It may not, however, always be easy for the beginner to determine what is the chief object which should occupy the central position, or which object or group to choose in a landscape. This brings us to speak of another important matter, and that is the right disposition of lines which form the L . Fig. 10. view or the selection of view so that the lines formed by the component parts shall fall in a desirable manner. The various objects in any view tend to form or suggest lines, thus in fig. 9 the outline of the trees, the banl- BARNET BOOK OF PHOTOGRAPHY. along the shore, the clouds, and the boats suggest the lines shown in the diagram, fig. 10, which lines all run the same way, but in fig. 1 1 we have a similar view in which the lines suggested counterbalance each other, and not only so, but by their convergence they carry the Fig. II. eye to a spot near the centre, and so make the boat, although not very large nor conspicuous, the one and principal object (see diagram fig. 12). For the sake of training one's perceptions look at Fig. 12. any good pictures, and in your mind resolve them into line diagrams and see how these lines fall, and in con- sidering any landscape or other subject to be photo- graphed make up your mind as to what lines are suggested, and then select your point of view so that PICTORIAL PHOTOGRAPHY. I0 3 these lines balance or are symmetrical in arrangement, and also that they converge towards some point well within the picture, and near the centre of it. Fig. 13- But in fig. 13 we have a subject in part well com- posed, but the composition is spoilt because of the line formed by the road and fence, which seem to cut the picture in two, whereas could we have chosen the same Fig. 14. subject from a point of view giving such an arrangement as fig. 14, a difference is at once felt and a more pleasing effect gained. 104 BARNET BOOK OF PHOTOGRAPHY. Lines which seem to separate us from the picture and cut off one part from another must be carefully avoided, and an endeavour to find something which will, as it were, lead the eye into the picture, should be diligently sought for, and indeed a subject, however it may interest us, must often be abandoned if it lacks those things which go to make pleasing composition, remember- Fig. 16. ing as we should always do that in pictorial work the fact that objects are curious, or interesting, or pretty, has nothing to do with the case, but that they are only to be valued according as they act as media for expressing PICTORIAL PHOTOGRAPHY. 105 pleasing ideas, beautiful thoughts and sentiments, which they will not do if some part creates a feeling of un- pleasing arrangement or design. If a scene does not compose well, we should as pictorial workers feel no desire to reproduce it. But you may say " Cannot we often by changing our point of view get an otherwise ill- composed subject to compose well ?" Most decidedly, that is precisely what we should do, but it is no longer the same subject or view. And now let me say that it is often surprising how much alteration may be made by changing our position. Figs. 15 and 16 are together an instance of this, the outline here given being made from a pencil sketch made on the spot, whilst figs. 17 and 18 are examples of Fig. 17. Fig. 18. the desirable change brought about by watching and waiting for a change in the position of light and the condition of the river's tide. Where the beginner most often fails is in taking things as they are without pausing to consider whether 106 BARNET BOOK OF PHOTOGRAPHY. they might not be improved, and if so in what way, and then patiently searching to see if such better way can be found. Pictorial success will as often as not depend on the exercise of fastidious taste, which is satisfied with nothing but the very best, and not quite content even then. A great deal more might usefully be said with reference to the composition of lines if space would permit, but this general reference may be given as a sort of summing up. If the disposition of the lines constitutes such a perfectly symmetrical design that it is at once recognised as symmetrical, then it is wrong, because the artifice by which pleasing composition is attained is betrayed, and we feel the thing to be artificial. If, on the other hand, the lines fall so as to make the beholder conscious of their presence, as, for instance, cutting off a portion of the subject or presenting, a one-sided appearance, again it is wrong. In neither case should the lines or the objects suggesting them be felt at all until sought for, neither as being very right or very wrong. In art it is a maxim that the means by which the thing is done should not proclaim itself, and hence it must apply to pictorial photography, which is an effort after the artistic. A composition should please without our quite knowing why, and without our being able to see the machinery, as it were, by which our pleasurable sensations are set in motion. But whilst it is convenient to speak of lines in the landscape, it is only a manner of speaking, for, as we know very well, photography, unlike pen drawing, has to do with " tones," that is, masses of light and shade. Now the general rules suggested as regards the arrangement of lines, applv in much the same \v;iy if we regard a PICTORIAL PHOTOGRAPHY. 107 picture (as we should do) as consisting of masses of light and shade. If when standing before a picture we close the eyes and then suddenly open them, our attention is certain to be drawn to the highest light or the deepest shadow, and hence, as a general rule, whichever of these is the strongest to attract attention, that should be in or near the principal object (indeed it will make of itself the principal object), and should therefore be well removed from the margins of the picture. Refer back to fig. 8, in which the light patch of sky, the light in the water and the two clusters of light rushes, all form competing points of attraction, and if these are too near the margins, they remind us of those margins, hence the improvement in effect when these are cut away or left out. But disposing of the highest light and deepest dark does not finish the matter. There is a certain relative degree of lightness and darkness between every- thing in nature. Moreover, colours have to be inter- preted by certain degrees of light and shade according to the distance objects are away from us, and according to the amount of light falling on them. Such relative lightness and darkness is called "tone." The word used in this sense has nothing to do with " tone " as applied to the colour of a print, which colour we change by a process we call " toning," and upon the correct rendering of relative tones so much of the effect of a picture depends, and so much of its emotional qualities. Generally speaking, although there are often excep- tions, the further an object is from us the grayer it seems. White becomes less white, and dark objects grow less dark, until in the distance both, under ordinary circumstances, come almost to the same " tone," and we see the distance only as a gray hazy mass. I08 BARNET BOOK OF PHOTOGRAPHY. If for a subject we have a figure of a woman by a stream of water and we make an under-exposed negative of it, or develop the negative to too great a density, we shall very likely have a print in which the water and the woman's apron and cap come very much whiter with regard to the rest of the subject than ever they appear in nature, whilst the distance will very likely come too dark. Here we show a disregard for the correct rendering of relative tones and the effect is hard and harsh, unlike nature. We must therefore endeavour, both in exposure and development and printing, to preserve relative tones exactly as they are in nature, and constant study and observation of nature should be carried on in order that the eye may be trained to know how things come relatively in nature, and so be able to decide at a glance if the photograph is good. Ultimate success, by the way, often depends less on knowing what to take and how to take it than on a well- trained judgment which knows what is good or bad when we have taken it. Whilst the mere lines or forms of objects may impart some amount of feeling and sentiment to a scene, inasmuch as there is restfulness and repose in the long horizontal lines of the river-side pastures, something rythmical in the sinuous curves of the winding stream, or vigour and variety in the irregular forms of the rugged cliffs and so on, yet the ideas and feelings which the picture will promote depend more on the lights and shades, and the masses contrasting or merging each with each. But Nature does not always present herself in pleasingly arranged masses, and is consequently at such times commonplace and unpicturesque in the literal sense of the word. At such times* she will not attract the pictorial worker any more than she will when per- chance the lines and groupings are unsuitable. PICTORIAL PHOTOGRAPHY. log The landscape which basks under the full blaze of sun, glittering throughout every inch with a myriad twinkling lights and sharp details, awakens no feeling akin to those which probably everyone feels when in the twilight of evening plane after plane recedes as one broad flat tint behind the other. Under the bright light of day we may wonder at the richness and plenty upon the earth, we may rejoice in that there are so many curious and pretty things to look at, but these are like the Fig. 19. feelings inspired by reading a book on natural history, rather than the emotions created by the perusal of a poem, or listening to sweet music. Compare for a moment the two photographs, fig. 19 and fig. 20. The first is by no means an extreme case of the ordinary photograph, and notice that although the com- position is fairly good as far as grouping goes, there is an absence of any quality which might make one feel anything outside the bare recognition of the facts no BARNET BOOK OF PHOTOGRAPHY. depicted, but the second, if it be good at all, must depend for admiration on a certain amount of sentiment which it suggests or creates. You will notice that in the first there is no sense of distance, and although a church tower, behind the masts of the boats, is half a mile or so away it does not possess the "tone" and veiling of atmosphere which would make it appear distant. Every part of the view seems equally near, or nearly so ; the eye wanders over the whole, alighting on details here and there which interest and amuse, yet there is an absence of just that breadth which is noticeably present in the second example. Now let it be distinctly understood that detail, its omission or suppression, and its introduction or sharp delineation, is not a question of lens focus only, or even chiefly;' but it is largely a question of light. ' Imagine the photograph, fig. 19, with the greater part of the detail PICTORIAL PHOTOGRAPHY. in taken out so that the quay, the houses, the shore, etc. were just broad masses of lighter or darker tone, should we not then get a composition which would be less disturbing, more compact, more concentrated in interest ? Is not this the case in fig. 20, in which detail is almost entirely absent ? And yet detail could not have been truthfully introduced in this photograph, because with the light in the position it is, and in the misty evening air, no detail was there to reproduce ; it was the fact that objects ranged themselves in masses one against the other, leaving room for imagination and creating ideas that determined its selection and its consequent portrayal. In many cases a clear and sharp delineation of details will perhaps be desirable, not, however, for the sake of showing detail, but just so far as the production of the effect may require ; on the other hand, just the full amount of detail that a lens will give is by no means always wanted. Lenses were not invented for pictorial purposes, and there- fore there is no reason for concluding that what the lens gives is necessarily right, for remember that we started with the distinct understanding that we were merely applying to a certain purpose just so much of the photo- graphic process as we considered we needed ; because I have the means of travelling at sixty miles an hour there is no reason why I should not apply the same means of locomotion to coaching a pedestrian at a tenth of that speed if I choose. It may be said that in the two photographs referred to the comparison is not a fair one, because so much depends on the sky. Granted that much in the second example does depend on the sky, which is an essential part of the picture, and indeed one cause of its very existence, but in the other (fig. 19) the presence of clouds would not improve the pictorial faults to which reference has been made. As a mere record or 112 BARNEf BOOlC OF PHOtOGRAl J HY. portrayal of Old Woodbridge Quay, the absence of clouds is as much a characteristic of its particular species, as the clouds in the second one are inseparable from its existence. So, but little more than half hinting at the principles involved in the due suppression of unnecessary details, and the elimination of undesirable objects in order to obtain breadth, and having said but little as to the preservation of correct: relative values or tones, I must pass on. Every corner of nature's broad expanse is, as it were, enveloped in atmosphere, and invisible as we are commonly in the habit of considering it to be, it affects to a greater or less degree everything we see, and the visible atmosphere is often responsible for some of nature's most beautiful and most appealing aspects. Obviously then we cannot afford to leave out so important a contributory to picturesque effect, and it is on this account rather than on account of sharp or un- sharp detail that the question of stops and lens apertures comes in. Look at the image of a landscape on a moderately hazy day, as it appears on the ground-glass focussing screen of your camera, using the lens at full aperture then quickly insert 7/32, and notice the difference. Not alone have objects near at hand and more remote become more sharply or more equally defined, but you may also notice that objects are more brilliant, and that a sense of atmosphere has been cut out. Compare if you will two photographs, the one made respectively with full aperture of//6 or//8 and the other made with //32 or//45, and provided that in the first case we have not actual blurring to the extent of destroying form and structure, does not the first remind you more of nature? I do not say it is so instructive, so surprising, so dainty, or of such exquisite finish, but is it not more PICTORIAL PHOTOGRAPHY. 113 reminiscent of the effects we remember to have seen and felt in nature. It is not the function of this article to say to what optical laws this difference is due, and yet the student may expect to receive something by way of practical working instructions. My recommendation is then to use a single land- scape lens or the single combination of a doublet, and in starting to use the full aperture. With this it may be that when the foreground is moderately sharp, trees more remote are so ill denned as to appear as a collection of little blots and irregular patches. Whilst sharp detail in all places may not be productive of pictorial effect, yet the extreme opposite will be displeasing in another way, and it will be best to secure just 'so much definition and no more as shall save the representation from appearing to have been wilfully put out of focus once let the destruction of detail be obvious and we betray the artifice by which we are working, which is just what we should avoid. In the case just supposed then, we may now intro- duce the first stop, simultaneously racking the lens in a little until we get middle distance without unpleasantly obvious blurring. The foreground may be a little out of focus, and in practice I find it is rather helpful to general effect if detail is sacrificed more in the foreground than in the middle distance. This I believe is contrary to the teaching of many, but my feeling is that with a sharply defined foreground the eye is attracted and the interest so far arrested, that it is difficult to travel further and enter into the poetry and sentiment of the scene beyond. Wide-angle lenses have a double disadvantage, shared in part by so-called rapid rectilinear doublet lenses. In the first place they flatten the view, bringing distant planes to appear as near as the nearer ones, and 114 BARNET BOOK OF PHOTOGRAPHY. by including a comparatively wide angle they bring into the plane of the foreground, objects so near that they appear out of proportion, and hence proportions are false when judged as the observer must judge by the standard of visual perspective. A long-focus, narrow-angle lens necessitates a camera which racks out to a considerable length, and probably a greater extension than any camera in the ordinary way can give, would be an advantage on some occasions. Passing reference has been made to the interpreta- tion of colours in nature in their true relative value of black and white. If we have a subject in which brilliant orange- coloured rushes in autumn are seen as glowing bright against a background of dark blue water, and the rushes made still more golden of hue by the ruddy rays of a sinking sun, a difficult case is before us. Such a case I remember very well in the south of Devonshire, close to what is known as Slapton Ley. It was late afternoon in November, and from over the rounded hills behind me to the westward, the declining sun sent warm red rays on to the belt of faded reeds which stretched out into the expanse of the still land-locked water of the Ley a great sheet of fresh water which placidly lay under the shelter of the bank of shingle which alone separated it from the ever-restless sea placidly listening to the ceaseless voices of sea music, and at this particular hour reflecting the sky deep blue and of almost leaden hue just above the bank rose the full moon, orange in tint, on a back- ground of blue-green sky the yellow reeds, kindled into glowing amber tints by the sun's rays, flamed out from the deep blue water yellow the shingle bank against the blue water and green-blue sky, deeper yellow the PICTORIAL PHOTOGRAPHY. 115 moon as it rose from out the sea. So grand a scheme of colour that by its side the essays of the most daring painter might well seem feeble, so exquisite a poem that the intrusion of the photographer, analysing the values and tones and calculating his powers of reproduction seemed like sacrilege. In the main it was yellow, orange- yellow, and red standing out as luminous against the deep blue of water and only a little less blue sky. It was gorgeous non-aclinic colour appearing as light against a highly aclinic but darker colour. The consequence of an indiscreet exposure with an ordinary plate might be anticipated to produce dark rushes against a pale grey background of water, and so probably the very effect we were minded to secure, reversed and dissipated. This is an extreme case, perhaps, but throughout the whole range of nature the contrasting and blending of adjacent colours is so subtle a thing that I should feel one were throwing away at least a possible advantage by not using colour-corrected or isochromatic plates on nearly every occasion, and in order to get the full advantage of isochromatic plates, I should consider the addition of a yellow screen an essential. The rapidity of one's plates, isochromatic or other- wise, iviust be governed entirely by the nature of the subject, as also to some degree must be development and subsequent printing. In every case I would endeavour to get a compara- tively thin negative, with even the portions representing deepest shadows slightly veiled. "Clear glass shadows" is an enormity and an outrage both of science and art ; equally are solid high-lights to be shunned. With modern printing methods it needs much less than actual opacity in the negative to produce white paper, and if the picture requires any part of it at all to appear as quite white, no subject will need more than the very Il6 BARNHT BOOK OF PHOTOGRAPHY. smallest region to be so. A general softness and very subtle gradation, with a total absence of " sparkle " and brilliancy in the negative, will yield by at least most processes the most suggestive print, bearing in mind that delicate gradations suggest atmosphere, and atmo- sphere is one of nature's most precious qualities. Whilst plain salted papers sensitized with silver present possibilities not yet sufficiently exploited, yet until such time that something more entirely satisfactory in all respects is given us in silver papers, platinotype and carbon, and perhaps also gum bichromate will be the processes most suitable for our purpose. Personally, platinotype has been the favoured medium, being, as I believe, more ductile and more amenable to various methods of control than is generally recognised. And leaving much more of importance unsaid than space limits admit of my saying, I must leave it. A. Horsley Hinton. Architectural Photography. O the majority of amateurs, the photo- graphing of architectural subjects presents consider- able, and in many cases apparently insurmountable difficulties. Undoubtedly there are difficulties to be grappled with, but they are neither so formidable nor so lumerous, but that any ordinary photographer with the average amount of com- mon sense can master them be he so minded. Unfortunately there are a great many who take up photography as an amuse- ment to whom the slightest departure from the ordinary routine presents a difficulty. It is however to the amateur photographer who desires to be able to portray archi- tecture, be it either of our cathedrals, churches, historic mansions, or places of personal interest, and at the same IlS BARX11T BOOK OF PHOTOGRAPHY. time wishes to be able to do the subjects fair justice, that it is hoped the following particulars may be of some service. To the beginner taking up this or indeed any branch of photography, size is of course a great consideration either from the weight carrying or pecuniary point of view. Another reason is the fact that young photographic workers have an idea that the smaller the plate, the easier the working. Sound though this reasoning may appear, nevertheless it is not entirely correct. As a matter of facl: all things being taken into con- sideration the larger the plate up to 12x10 or 15x12 employed the more rapidly will the worker progress. Large plates, especially in architectural work, tend to make the operator more careful and conscientious when out with the camera ; and even more so when in the developing room. So much more can be done with a large plate than with a small one ; the use of a large plate moreover checks the common failing so prevalent among amateurs of rushing work and recklessly using plates. Taking all things into consideration, I would strongly recommend the whole plate or 10x8 camera to the student taking up this branch of our art. In selecting a camera purchase a front extending one with bellows only slightly tapering. See that it has both rising and cross movement to the front, and also that the amount of movement in each case is a not too restricted one. Makers, unfortunately, do not give sufficient attention to this matter, the usual rise allowed being very slight whereas it should be at least equal to one-third of the longest way of the plate ; even more than this is advantageous if it can be obtained. By the rise I mean the amount of upward movement that can be obtained, the lens being in the centre before starting. ARCHITECTURAL PHOTOGRAPHY. Jig The cross-front should have a movement of about one-quarter of the length of the plate each way. It may be useful to know that a little more rise can be obtained by the placing of the lens above the centre of the cross-front; reference to the photograph of camera will explain this matter more fully. The swing-back should be a practical one, working from the centre, and capable of being swung either to or from the lens. In many of the cheaper front extension cameras it is not possible to use the swing-back when tilting the camera down, only when tilting upwards. The swing- front, although not an absolute necessity, is undoubtedly a movement possessing great advantages, especially when the front is raised rather high, and one is using a lens of limited covering power This movement should be acquired if possible. The camera should possess double extension, focus- sing by rackwork, and having a reversing back so made that it will fit on all ways ; it is then possible to draw the slide shutter out in any position. In selecting a tripod stand purchase one of the kind known as the sliding leg variety, two-fold is better than three, giving greater sliding power. The top of stand should "be as large as possible ; this is preferable to a turntable, as this piece of workmanship is seldom rigid after a little use, and some difficulty is experienced when trying to spread the legs out rather wide. A two-fold Ashford stand is as good as any on the market. The blocks herewith illustrate the kind of camera used by myself, and with the exception of the turntable, which is not a great success, it answers all requirements. In the selecting of suitable lenses a great deal will depend upon the inclination of the purchaser and the depth of his pocket. I2O BARNET BOOK OF PHOTOGRAPHY. There is such a great variety upon the market at the present time, that to the young photographer the buying of the right lenses is somewhat a difficult problem. The Zeiss series are undoubtedly the finest obtain- able and for architectural woik are unrivalled, possessing great covering power, good marginal definition, and in fact very fine definition all over the plate. The lenses of this series, although quite new, have met with great favour amongst architectural workers. They work at an aperture of //i8, but I understand that they can be opened to//i6 and numbered on the/ system. As regards their relative working capabilities they give about the same picture at 7/32 that the majority of wide-angle lenses give at 7/64. The Goerz anastigmats are also another very fine series but do not give anything like the covering power of the last mentioned, and moreover are nearly double the price. Their special merit is that one can work w w K IE "" O ARCHITECTURAL PHOTOGRAPHY. at f/S or //i i, and get a picture sharp up to the edges. Taylor, Taylor & Hobson also make a good wide-angle lens, possessing great covering power and at a moderately low price. With one of their nine inch lenses I have covered a plate 12 x 10 inches. For a whole-plate camera, a useful battery would be a 5 inches, 7^ inches, 9 inches and 12 inches ; for lox 8, 7 inches, 9 inches, 10^- inches and 14 inches. The three last in each case are the most useful. Having selected the lenses, another very important point and one not to be decided hastily is the question of levels. Four are required, two circular and two ordinary. They are placed as follows : Fix the circular levels, one on the baseboard near the front of the camera, the other on the top of the back part of camera. The other two should be placed one on the side of the back part and the other on the back of camera just under the reversing back. Care must be taken to purchase slow moving levels as some work so quickly that it is next to impossible to level the camera with them, and as this is one of the most important points in the whole t^us.iness, too much care cannot be taken in selecting and, fix jng the right kind of level. . oqx9 ., flj , ru; onr, 3 fr/i9arj siorrt sdt ?.\ <>how tohr/Jrri 'u ;' The focussing screen should be ruled as accom- panying diagram. This will divide the screen into inch squares, working from the , centre, and. IwiU .considerably assist the photographer in " sizing his si 122 liAKNiiT BOOK Ol- 1'HOTOGKAPHY. One other thing required is a set of clamps for binding the tripod legs together. These are, I believe, made by George Mason, of Glasgow, but any dealer will procure them for you. The use of the right kind of plate constitutes a very important factor in the production of a satisfactory negative, particularly in this branch. Owing to the greater difficulty experienced in devel- oping extra rapid plates, one generally sees the slower variety recommended. No hard and fast rule can how- ever be laid down. To gain the best result, the plate must be suited to the subject. For instance, in a very dark interior in which heavy black shadows predominate, many of them appearing much darker than they really are owing to their close proximity to a strong light, the quicker the plate used the better. This tends to break down the harsh contrasts, and at the same time the shadow detail is considerably better rendered. On the other hand, working in a light interior or one which is flat owing possibly to the large amount of light present, a slower plate can be used with advantage, and, providing the exposure is sufficient the result will be all that is wished for. Exteriors, particularly those in sunshine, should be photographed on a fairly quick plate. Slow plates, although good, do not yield nearly such good negatives, and unless very fully exposed give excessive hardness. Taking this class of work all round, the quick plate is the more useful of the two and is undoubtedly the best for interior work, particularly such interiors as one meets in our English cathedrals. For all subjects possessing strong high-lights, such as windows, stained or otherwise, rapid plates combined with a suitable backing composition yield the best results, ARCH1TKCTUKAL PHOTOGRAPHY. 123 and I would impress upon the reader the fact that no plate should ever be placed in a dark slide without being covered at the back with a suitable composition for the prevention of halation. The value of this agent is distinctly demonstrated by the accompanying illustrations, and I would point out the fact that the negatives were both developed with the utmost care. The unbacked plate was so developed as to prevent the appearance of halation as much as possible, and it" will be noticed that all portions of the photograph, 124 BARNET BOOK OF PHOTOGRAPHY. other than that where halation has occurred, are nearly as good in the unbacked as in the backed one. Having obtained all the apparatus and materials, a very good subject to begin on and one giving good opportunities for the exercise of the various movements connected with the camera, etc., is a general view of the rhoir in some cathedral or church near at hand. Having erected the camera, the next thing is to decide upon the most pleasing point of view. Speaking from my own experience I would advise the shifting of the camera either to the right or left, so that the centre aisle is thrown slightly in perspective. This tends to give a much better and decidedly more pleasing effect to the resulting photograph. Of the two sides, moving to the right seems to be the best. The next item is the fixing of your ground line, this must be so arranged that it is quite clear, not obstructed by the backs of chairs, etc., which look very badly if left standing. Personally, I have generally found it necessary to move one or two rows of chairs so as to make the ground line myself. In adjusting the height of the camera from the ground it is well never to exceed six feet. Five feet to five feet six inches is the most useful height. This will give a photograph in which the point of sight is the same as that of the person actually viewing the subject. The placing of the camera on step ladders, chairs, or other supports, so as to overlook objects in the immediate foreground is a practice to be condemned, giving results very rarely pleasing and always bad from the sightseer's point of view. Having settled upon the point of view and the lens to be used, the student should then roughly focus the image. Notice the amount of subject on the plate and how much rise is required. AkCHiTKCtURAL PHOTOGRAJ>HV. 125 If having a camera such as described, the rise is easily accomplished and the camera can then be truly levelled up. Care should be taken over this as unless you have the camera exactly level you cannot expect a true picture. The bubbles of the levels should be exactly in the centre, a little bit out will not do. If it is found that the rising front fails to give the amount of subject required, recourse must be made to the swings, and it is here that the swing front triumphs over the swing back. 126 BARNET BOOK OF PHOTOGRAPHY. To swing the back necessitates the shifting of thr camera and tripod stand, and at once throws all the levels out of gear. Then comes re-focussing, etc. Some- times this will have to be gone through five or six times before the desired amount of swing has been achieved. Owing to the re-focussing required every time the camera is moved it is very difficult, especially for the beginner, to rightly estimate the amount of rise required. With the swing front the desired amount of rise is attained easily and quickly, and it can be worked with the head still under the focussing cloth, which is a great convenience. At the same time the baseboard and back of camera always remain level. After gaining the correct amount of rise the sides of the subject should be considered. A golden rule to remember in this class of work is when you show a column, show the base of it, and always start the sides of plate with either half or three-quarters of a column. It looks very queer to see the bend of an arch wandering away out of the side of the picture without any apparent support. In arranging the sides it is usual to have a preponderance of subject on the opposite side to which the camera is, and to start that side with a column. Sometimes the subject fails to fit the plate nicely, in that case it is better to trim the print than to have un- interesting features present. Of course a great deal depends upon the personal taste of the worker, what one man considers right another will rebel against ; so although I advocate the use of columns to fill the sides of the plate it does not follow that that is the one and only method of photo- graphing these subjects. The student having carefully gone into these matters and arranged the subj sets to suit his own satisfaction the question of what point to focus for arises, and indeed in ARCHITECTURAL PHOTOGRAPHY. 127 very dark interiors the question of focussing anything at all comes in. A method I use myself is to roughly divide the distance from the camera to the farthest object in half, and then to focus midway between the camera and the middle of the subject. Then stop down the lens until the most distant object is sharp. In practice I have found this rule so good that I can recommend its adoption for all subjects, and if carried out correctly will always result in the production of crisp negatives. Exposure is not a very difficult thing to overcome. Arrange the focussing cloth well over the head, open the lens out to its largest aperture and remain under the cloth until you can see the image distinctly all over the plate. Then without uncovering the head proceed to slowly stop down until you can only just see the image all over the plate. Now using a plate of the rapidity ot Barnet extra rapid, an exposure of ten minutes will yield a satisfactory fully exposed negative. The varying exposures for other plates and stops are easily obtained. For instance you find the imago can just be seen all over at 7/32 and you wish to use//6.j The exposure will be forty minutes. After having used this method for over seven years, and haying invariably found it correct, I can un- hesitatingly recommend its adoption, and if used with a little common sense the worker will seldom suffer from his plates being either badly under or over-exposed. In photographing side aisles, transepts, or long rows of pillars, the worker is often troubled by the unnatural way in which the floor runs up. This is more especially noticeable when there are no prominent objects in the immediate foreground. A considerable amount of this can however be overcome by the lowering of the camera to about three feet from the ground. It is here where the sliding legs of the tripod stand becorr of service. 128 BARNET BOOK OF PHOTOGRAPHY. I would ask the student always to use the longest focus lens possible, consistent with the effe<5l desired. The use of extreme wide-angle lenses has had a disastrous effe<5l upon the public taste in respect to archi- tectural photography due principally to the abortions one sees exposed for sale in the shop windows of our cathedral cities. It should be seldom necessary for the amateur to use very wide-angle lenses. Of course, when it is a question of getting a detailed photograph in a confined situation a wide-angle lens is of great service. But it is when you see the whole length of a cathedral photo- graphed on a whole plate with a five inch lens that the fault is so noticeable. In photographing exteriors great care should be taken in the placing of the camera in a suitable spot. Try and so arrange it that the short side of the building does not run off too violently, indeed, it is often much better to leave out a portion of the subject rather than to cram the whole subject upon the plate. General views are much better if photographed when there is a little sunlight. This gives to the subject a sharp, clean-cut appearance. Details on the other hand are better if photographed in a subdued light and slightly over-exposed. In focussing very high subjects some difficulty will be found in getting bottom and top in focus at the same time, especially if the lens be strained by either altering the back or front of the camera. The best place to focus is a little way above the centre of the screen, so that when stopped down the bottom of the building is quite sharp. A slight softness towards the top of the subject is scarcely noticeable in the final print. ARCHITECTURAL PHOTOGRAPHY. I2g The exposure of exteriors varies between three seconds at 7/64 to ten minutes, and no correct guide can possibly be given. To the beginner a Watkins' exposure meter will here be of some service. If people are continually passing and repassing stop the lens down to 7/64 and give as long an exposure as is possible ; this will as a rule completely obliterate them. I have found that an exposure of from ten to twenty seconds entirely destroys all trace of moving objects. Another method of making an exposure where there is much traffic past the building, and perhaps people standing about whom you cannot very well ask to move, is, to break the exposure as many times as possible. Expose for two seconds, then wait until the traffic has somewhat altered ; then give another two seconds and so on until finished. By this means I have been able to photograph buildings in the centre of a crowded street or thoroughfare without a trace of anybody showing. It is often interesting for the student to be able to successfully tackle the photographing of drawing-room, ball-room, or other apartments either of his own or friends' houses. This work is considerably more difficult than it seems ; and it is in such subjects that the taste of the operator becomes manifest. A great deal depends upon the point of view chosen and also upon the arrangement of the furniture. If a long room, the camera should be placed at one end at about a quarter of the width of room away from one side and from the end wall. Keep the camera parallel with the sides of the room and use the sliding front so as to obtain more of the opposite side of the room. This will give the ceiling a true square appear- ance and the side of the ceiling will not mn off with an unpleasing effect. 130 BARNET BOOK OF PHOTOGRAPHY. In some subjects it is perhaps necessary to include one or more windows. This can of course be accom- plished by the aid of backed plates, but it is always better to block those particular windows out. This is usually done by covering the outside with black cloth or brown paper or pulling the sun blinds down. To get the effect of the windows you must remove the paper or cloth at the end of the exposure for a few minutes, three minutes being generally sufficient. By this means it is possible to show the landscape as seen from the window. Do not place your camera too high. Four feet to four feet six inches is quite sufficient. If the camera is higher you lock over the immediate foreground objects, touching the ground past them, which is undesirable. In arranging the furniture be careful that round or oval objects are not placed so that they appear on the edges of the plate which gives them an exaggerated appearance. In exposing on all such interiors I would strongly recommend a very full exposure, the object being to flatten the subject. A great thing to study in this branch of work is the careful lighting of your subject. This can be largely varied by the use of the inside blinds, also by the sun blinds found outside many windows. It is not advisable to draw the blinds up to their fullest extent. By so doing you accentuate your cast shadows thrown by tables, chairs, etc. In fact, the softer the light in the room coupled with a corresponding exposure, the better the result. Another point to notice is that a comparatively dull day is often the best for interior work, the light being much softer and subdued. As a slight guide to exposure I would suggest that an additional twenty-five per cent, be added to that recommended for church work. John H. A very. The Hand Camera and its use. HAT is the best form of hand camera ? How often this question is asked, and yet how impos- sible to give any definite reply, IJ^J the conditions of use, and .1 . requirements of each worker >-C? being so widely different. One, desires a form of ap- paratus, capable of being -^H BaT" IV i closed up into the smallest space, weighing but the least possible number of ounces, the necessary movements, confined to touching a spring, or pressing a button, and the total cost not to exceed two or three pounds, while others do not care so much as to its possessing these qualities, if by a little increase in bulk, weight, and cost, it is capable of use in a less restricted manner, on subjects of wide variety, and under such conditions of light, and atmospheric effects, as, when shutter exposures are being given, call for the maximum light passage to the plate. 132 BARNET BOOK OF PHOTOGRAPHY. Assuming the camera to be intended exclusively for use without a tripod, then it becomes not a difficult matter to point out its essential features. First and foremost, it should be characterized by simplicity in con- struction, and every part be easily accessible, com- plicated movements being rarely found necessary, except perhaps, to raise the price of the instrument. When being employed in the field, the camera and its working parts ought not to need the slightest consideration, each movement, whether they be few, or many, being made, without requiring troublesome attention at the moment when every thought should be devoted to the subject. The component parts of an instrument, complete and effective for this class of work, may be taken to be a good lens capable of covering at //8, a shutter, some simple means of focussing, adequate finders, and the means of carrying plates either in some form of magazine, or ordinary dark slides. Each system of holder for plates possesses its own distinctive advantages, which are preferable, depending entirely on individual needs, or tastes. Some admire one method, and some the other. When plates are carried in one of the many forms of magazine which cameras are nowadays fitted with, it is important when re-charging it, that care be taken to see each sheath and plate is laid true in its place, as the slightest irregularity at this point, means certain trouble when changing a plate after exposure, indeed, perhaps fifty per cent, of the misfortunes which occur when out at work, from failure to act of the changing arrangements, are directly caused by carelessness when laying the plates in the magazine. Given reasonable care in this matter, almost any of the modern automatic changing methods, may be relied on to answer satisfactorily. When however the slight additional bulk, weight, and it THE HAND CAMERA AND ITS USE. 133 may be increase of cost is not objected to, then there can be no denying separate dark slides possess many and important advantages. No need to fear a wasted day, caused by some plate sticking, and rendering further work impossible, without having recourse to a dark-room, which probably is miles away ; and again, one must not overlook the opportunity they give of carrying plates of different degrees of sensi- tiveness, a matter of service, when subjects to be dealt with are varied, such as, say, clouds and water, landscapes and figures. In the first case, when light is fairly good, the ordinary speed plate will be found amply quick enough during the daytime, and fifty per cent cheaper in price. When open landscapes are being taken, during summer time, medium rapid plates generally will be quick enough, but many opportunities, for pictorial work, arise under conditions of atmos- phere and light, in which to obtain fully exposed negatives with a shutter, demands a plate of extreme sensitiveness, and if for no other reason than that they offer this opportunity of carrying a varied assortment of plates, many workers prefer dark slides, to any form of magazine. There are advantages, and disadvantages, with both systems, and it becomes simply a question for each worker to consider which fulfills his requirements best. The Lens. Good work can be, and is done, with cheap single lenses, but the opportunities offered are considerably restricted, what is needed, being such a lens as may be used at full aperture of //8 or //6, and will then cover the plate from corner to corner, sharply. This is necessary not only because the aclinic quality of light is not always over good, but that moving subjects demand the shutter should be working with rapidity, sometimes indeed with considerable speed ; under which 134 BARNET BOOK OF PHOTOGRAPH V. conditions two factors are absolutely essential, a large working lens aperture, and a rapid plate. It is well, therefore, to buy the best lens you can afford, it more than pays in every way. For ^-plate work, a. rectilinear of 5, or 5^ in. focus, working say at //5'6, and with iris dia- phragm, by one of the best makers, will allow work being done under any condition of weather, or other circum- stances, when shutter work is possible. Finders. Years ago, the question of whether finders were necessary, or not, in a camera of this kind, was a matter on which some at least expressed very different opinions, from those now held by most workers. Further experience has shown that when certainty in working is desired, some kind of finder is an absolute necessity as part of the working mechanism. It usually takes the form of a small camera obscura, what is required being, that it should not be too small, should give a perfectly discernible image, and be so adjusted, that only so much of it is shown, as will be projected on to the sensitive plate, when the exposure is made. The reason of its im- portance is that it enables the subject being arranged tastefully, as well as ensuring that the whole of it is on the plate. Where no attempt at pictorial work is intended, and the important matter is simply that the object being photographed should be in the centre of the plate, then it is only necessary that the finder should show as wide an angle of vision, or a little wider than the lens being employed inside the camera. But when something more is aimed at, viz. : Tasteful composition over the whole plate, then it is necessary to block out on the finder all excess of view, beyond what will be received on the sensitive plate. The Shutter. What particular form may be best is a matter of doubt, but whatever it be, exposure must be possible without vibration, it should give greater THE HAND CAMERA AND ITS USE. 135 exposure to the foreground than the sky, and ought tc allow of being regulated for exposures ranging from ^th ol a second up to perhaps T ^th, for ordinary work. Where shutter work has to be done, which demands anything less than T j5 BARNET BOOK OF PHOTOGRAPHY. removing the bottom sheet to the top and passing through the whole in this manner, turning over each sheet and removing all air bells, even saturation is secured. Each sheet is carefully and slowly removed from the solution and dried in the dark. The paper is now very sensitive to aclinic light, which must during all future operations be carefully guarded against. After the paper is dry, it will if kept so be in good condition for a long time. To prepare the gum mucilage, take two ounces of Soudan or Turkey gum and dissolve it in five fluid ounces of cold water, strain out the floating impurities through fine muslin, and allow others, and finer to subside. This mucilage will keep in good condition in a well-corked bottle, for a considerable time. M. Demachy employs gum mucilage of twice this density. Pigments in powder are more suitable than in any other form, if in cakes or paste. The medium in which they are prepared, does not work kindly with the gum, and it is also difficult to accurately measure quantities. No advantage is gained by using expensive colours, they can all be purchased at a good colourman's, and at a small cost. Lamp or any carbon, black, red ochre, yellow ochre, burnt sienna, and ra-w sienna, all work well; there is some uncertainty with the umbers and sepias. It will be found that much time will be saved if a combination of these dry colours is made up in bulk, as for instance one hundred and seventy-five grains of vegetable black and one hundred of burnt sienna, give a rich soft brown colour. These must be finely and intimately mixed with each other, which is conveniently accomplished by grinding with a small pestle and mortar ; after which the mixture may be kept in a wide-mouthed bottle. Another advantage in thus keeping combinations of dry colours in THE GUM-BICHROMATE PROCESS. 247 bulk, is the absolute certainty of repeating the actual tint when required. Various combinations of similar mixtures can be made. Of course it will be understood that any or all of the above-named colours may be used singly. The grinding of the pigment with the mucilage is easily done on a stone slab with a palette knife. Take half a fluid ounce of the two in five gum mucilage, to which add the same quantity of water and thoroughly mix. Weigh out fifteen grains of the mixed pigment and place in a heap on the slab, add a few drops of the diluted mucilage, grind and regrind the mixture until it is com- pletely smooth, then remove it to a cup, and clean the stone with another portion of the reduced mucilage, finally adding the whole of the ounce, intimately mix, and it is then ready for coating the paper. For extra fine work on smooth paper, and in fact for all classes of work, the fine grinding of the colours adds materially to extend the range of gradation, and although the trituration may be carried out fairly well with a palette knife, when the finest possible grades are desired, recourse must be had to the muller and stone. Mullers are obtainable of any artist's colourman, they are made in glass, and a convenient size is about one inch in diameter. The most convenient brush for applying the mixture of combined gum and pigment to the paper, is of the description known as bear's hair, these are usually set in tin ; a flat one about two inches wide is a useful size. In order to coat the paper evenly, pin it down to a drawing board by each corner with a double layer of blotting paper an inch or two larger than the paper to be coated. The blotting paper will absorb the excess of colour at the margins and enable you to secure an even coating up to the extreme edge. 248 BARNET BOOK OF PHOTOGRAPHY. Take a fairly full brush of the mixture after thoroughly incorporating the colour and spread it evenly over the paper, crossing and recrossing it with the brush. Allow the mixture to lie upon the paper for a second or two so that the paper may expand ; now release each of the corners and pin the paper down again. Upon the next operation depends the evenness of the coating. Take a four inch wide artist's badger's hair softener, hold it vertically and lightly by two fingers and the thumb about an inch and a half from the top of the handle, and pass it rapidly over the whole surface of the paper as quickly and evenly as possible. The motion producing the best effect is not the usual sweeping action, but a series of sudden short jerks, difficult to describe but easily acquired. Continue this softening down until the paper has an even semi-transparent surface without uneven cloudy spots. Allow it to dry spontaneously, but before it is stored for future use dry it carefully by the fire, but avoid overheating. Uncertainty of result is a defect often brought into argument against this process ; but absolute uniformity is not difficult if strictly accurate quantities only are employed. With constant strength of bichromate and gum, uniform weights and combination of pigment, similarity of repeats are obtained : but these can only be secured when each sheet of paper is coated identically with its fellow. To get this evenness the badger hair softener must be washed out and dried after coating each sheet. This is very quickly accomplished by an ener- getic shaking and drying upon a smooth towel. If the paper has been coated properly, it has an even semi- transparent surface slightly glassy. Failures often occur from using an excess of pig- ment and allowing the gum to become too thick in THE GUM-BICHROMATE PROCESS. 2.JQ consequence of evaporation. Excess of pigment gives dense heavy shadows and increases the difficulty of printing ; excess of gum gives clear high-lights, tending to hardness and easy solubility endangering the half- tones. The paper, if it has been correctly coated will work satisfactorily, if on steeping a small piece of it down- wards upon cold water, the pigmented gum dissolves and drops from the surface leaving the paper nearly clean. From ten to fifteen minutes should complete this test. The method of working without previously chroma- tizing the paper is as follows : Take half a fluid ounce of four-in-ten gum mucilage and add to it an equal quantity of saturated solution of bichromate of potass; to this, with all care as to grinding and mixing, add the pigment ; coat the paper as before directed. This method will be considerably slower in printing than that in which the paper had been previously saturated with the bichromate ; neither are the whites as a rule quite ?o clear; but it will possess a peculiar grain and softness not otherwise obtainable, which is much appiovcd by some workers of the process. Exposure is so much dependent on circumstances that it is difficult to give precise directions, being governed by the density of the negative, the thickness of the coating and the intensity of the light. Even and not too dense negatives are the more suitable, for if the intermediate and high-lights are over dense the shadows are considerably over printed before the lighter parts can be brought out. Skill in development can do much to overcome these defects, but they may be considerably modified by the judicious employment of matt varnish, and by other methods of locally retarding printing. R 250 BAKNET BOOK OF PHOTOGRAPHY. The greatest assistance in obtaining uniformity in printing is the employment of a reliable aiftinometer, Wynne's print meter is probably the most useful for this purpose, with ordinary gelatino-chloride paper as a register ; from twelve to sixteen numbers will be mostly sufficient for an ordinary negative, on not too thickly coated paper. Another method of judging exposure is by the appearance of the shadows ; they may frequently be seen by transmitted light, and when well out printing may be judged to be correct, but this is a slovenly method and only approximately correct . at the best. If the bichromate is used only in the pigmented gum, without previous saturation of the paper, exposure must be much more prolonged. By no other process is it possible to obtain such diversity of effect as by this ; much will, however, depend on the skill which is exercised in development. Should the printing exposure have been fairly correct it is a simple procedure. The print is floated face down- ward upon cold water contained in a deep dish; see that all parts are equally acted upon by the water, and that no air bells exist ; if any, they may be easily removed by gently raising the print and immersing it again once or twice. After it has been soaking some five or ten minutes it may be examined ; if all is going well, and the exposure has been approximately correct, the pig- mented gum on the unexposed margins will have left the paper, and possibly some of the high-lights and half-tones may be making an appearance, if so, the treatment must be of a gentle character, and the print may be safely left for some time longer in the same position face downward ; never allow it to lie either in or out of the water face upwards for any long time, or unremovable stains will be developed. Many prints THE GUM-BICHROMATE PROCESS. 251 will develop almost entirely without assistance, or with only an occasional laving of water if allowed to lie in this position for a long time. On the other hand some may, even when only slightly over-printed, give no indi- cation of development. When this is the case remove the print from the water and place it face upwards upon a thin, smooth board, fix it in position with one drawing pin on the extreme margin, then gently lave cold water over it ; should some of the darker parts still resist this action, longer soaking will be found advantageous. If there are still parts on which the colour will not move, recourse must be had to the brush, and for this purpose nothing is better than a large camel's hair mop. Keeping the brush always full of water, touch where necessary very softly; do not sweep it up or down, but just dab here and there as may be required, constantly flowing over the surface a copious supply of water. If there are still parts in the shadows, or even in the high-lights that will not move, a jet of water from an enema syringe or from the household service pipe is very useful. As a last resource a prolonged steeping in water of varying degrees of temperature, even up to the boiling point, may be resorted to, but the application of increased temperature requires judicious manage- ment. When the print is sufficiently developed, if the creamy yellowness of the chromate stain is not desired, the print must be cleared or bleached, either in a solution of alum, sulphite of soda, or hypo-sulphite of soda, strength being immaterial with a careful after-washing. If the print is only just sufficient or only slightly over- printed, care must be taken that the clearing bath is not acid, neither must the washing be too prolonged, but if 252 I3ARNET BOOK OF PHOTOGRAPHY. the print is first dried and submitted to light, this pre- caution is unnecessary. Always allow the prints to dry spontaneously. It will not do to use any kind of pressure or blotting paper, for the surface of the colour is very tender and delicate. Jos. PacMam, F.R.P.S. I 253 An Introduction to Carbon Printing for Beginners. N the article that follows next will be found a complete exposition of the carbon process, with its various adaptations from the preparation of the paper and material forwards. Whilst at the present time carbon printing is more largely used by professional photographers, yet its sim- plicity, the absence of chemical formulse and com- plications combined with the beauty of the results, makes it eminently suitable for amateur workers, and hence it has been thought desir- able that as an introduction to the subsequent article, ;i brief and simple outline of the process should be given for the benefit of those who have not hitherto made its acquaintance. 254 BARNET BOOK OF PHOTOGRAPHY. In the first place then let it be understood that in carbon printing instead of depending on light to make a visible alteration of the sensitive salts as in silver printing, we expose the prepared paper or " tissue," as it is called, under a negative and secure a positive in insoluble gelatine, the gelatine having combined with it a pigment, and hence we get an image in pigment, not in platinum, or silver, or gold, but in a simple pigment which may be of any colour. If bichromate of potash is mixed with an organic substance such as gelatine, that gelatine becomes insoluble after exposure to light, and if that gelatine carries with it a pigment, then on becoming insoluble it holds the pigment with it. If now, paper or other material be coated with bichromate, gelatine, and pig- ment, and exposed to light under a negative in the usual way, the thin portions of the negative will admit of the light acting on this coating and making it insoluble, whilst the parts which are protected from light, as for instance the sky or white objects, will remain unchanged and soluble, and on being washed in water will dissolve away, leaving white paper, whilst the light-affected portions which have become insoluble remain in pro- portion as the light has penetrated the various densities of the negative. This then is how we obtain our print. For fuller explanation of the paper or "tissue" and its manufacture the reader is referred to the next article. The beginner will certainly first obtain his tissue ready made, and he can purchase it ready sensitized or otherwise. The former will be best at the outset, but it must be borne in mind that it should not be kept longer than can be helped before use, and never more than ten to fourteen days at the utmost. Various shades of blacks, browns, and reds are the usual colours, also grey, green, and blue. The tissue is rather more sensitive to CARBON PRINTING FOR BEGINNERS. 255 light than silver paper, and should therefore be opened and handled in subdued light. It must be kept as dry as possible. A rather vigorous negative is best for carbon printing, one not too strong in contrasts. Before placing the negative in the frame, we must give it what is termed a " safe edge." This is done by making a narrow border, say of about a quarter of an inch or less, round the negative, either on the glass or film side, with opaque black varnish, or it may be done by gumming on narrow strips of paper, such as lantern-slide binders. If binders and not black varnish are used, they must be applied to the glass side. The Carbon printing paper which will hereinafter be called the "tissue" will be found to present an un- promising appearance, and as the coating is the full colour of the pigment in which the print is eventually to appear, it follows that the progress of printing will not be visible, and a mechanical means of gauging the exposure must be resorted to. An adlinometer, similar to that described in the article on Platinotype, will do, and another and simpler form is described in the next article. Printing will occupy about one-third of the time occupied by gelatine-chloride of silver paper. Development is conducted in daylight, but not too close to a window. The absence of chemical solutions has been suggested as an advantage, in this process the developer being merely hot water. It is not necessary to have this laid on, a can of hot water close at hand and a kettle on the fire or gas stove not far off are all that are required. We shall require four or five dishes, one at least of which should be a good deal larger than the size of the prints we are to develop and several inches deep a good-sized pie-dish or a basin will do. 256 BARNET BOOK OF PHOTOGRAPHY. Development merely consists of washing away the unaffected and therefore soluble coating, but it must be remembered that the less affected portions representing the half-tones have received their modicum of light on the surface, and therefore the soluble part of the film is underneath the part that has like a surface skin become insoluble. This necessitates the printed film or tissue being transferred to another paper or "support," so that we may develop or wash away from the back. In procuring your carbon tissue order at the same time a packet of Single Transfer Paper, which is paper with a thin coating of hard gelatine. Now to proceed. Place a piece of single transfer paper into a dish of cold water, and in three or four minutes the coated side will feel slimy, then place in the same dish a piece of the printed tissue face upwards. This will probably curl up at first and afterwards flatten out again. When this has happened or in a few minutes after immersion bring the piece of single transfer paper and the print together, film to film, so that they may be in contact:, and square one with the other. Now holding them by one edge, withdraw them together by sliding them out of the dish on to a sheet of thick glass, a large cutting glass serves well, or stout sheet of zinc. This should be supported in readiness at the rim of the dish. Having the transfer paper and print now on the glass or zinc, hold them firmly and with a rubber squeegee press them closely into contact, squeezing as much water out as possible. A better way perhaps is, if the dish is large enough, to place the glass or zinc under the two papers whilst in the water and so raise them out. The squeegeeing must be done thoroughly, firmly, and all over several strokes being given in each direction. CARBON PRINTING FOR BEGINNERS. 257 Next lift the papers, now in firm contact and sticking together, and place them between blotting paper on which is a heavy weight. The next print may now be proceeded with and so on. The print should be between blotting paper and under pressure for about twenty minutes, after which it is removed to a dish of hot water almost as hot as the hands can comfortably bear, say 100 to 120 F. After lying in this for a few moments the dark pigment will be seen to be oozing out from between the two papers. When this has begun to come pretty freely take one corner of the print and pull it away from the transfer paper. It should come quite easily, and on being peeled off entirely it is thrown away. We have now the transfer paper bearing the printed film reversed, that is, the side which was previously at the bottom and next the original paper support, is now uppermost and can therefore be got at. If we splash it or lave it with the hand, using the hot water, we shall soon see what happens. The smudgy mass of pigment begins to wash away and the picture gradually appears. This constitutes development and we continue working it with hot water until the whole is clear and bright, being careful not to touch the film with fingers or anything but water, for being in a very delicate and soft condition it would be certain to sustain injury. The hotter the water the greater its washing-off action, and hence in cases of over-exposure very hot water may go far to recover the print. When the desired result is secured, transfer the print to a dish of cold water, this instantly tends to slightly harden the film by cooling it, and after two or three minutes it is passed into a dish of alum and water, which further hardens it and also " clears " the print of any bichromate salts 258 BARNET BOOK OF PHOTOGRAPHY. which may still remain. In the alum bath the print should remain until any sign of yellow stain has dis- appeared, when after a final rinse of a few minutes in cold water to remove the alum, the print may be hung up to dry. It will be seen that there is no prolonged washing as with those processes in which hypo is employed, and the print is absolutely permanent. It must be remembered, however, that in the finished picture we are looking at the back of the printed film as it received the light impressions from the nega- tive, and hence the image is reversed, that is, the left is on the right and the right on the left. For landscape and views this reversed position will probably be of no importance, but if it is desired to have things right way round in portraits it will be essential we must either work from reversed negatives, or we must again transfer the film which will then constitute a double transfer. We shall now understand why previously we called the paper to which the film was transferred single transfer. Inasmuch as it will be seen that the print is not on paper, but consists of a transferable film of pigmented gelatine, it will be understood that the paper employed is merely a support to that film, hence it is customary to speak of the paper as the support, whilst moreover it maybe, and as often as not is ivory, glass, textile fabrics, wood, or other substances. If no\\ we wish to again transfer the film so as to correct the lateral reversal, we substitute for the single transfer paper a " temporary support." The temporary support which is to receive the film merely whilst it is being developed, and with the intention of its being subsequently transferred again to a final support, may be paper or many other things. CARBON PRINTING FOR BEGINNERS. 259 Moreover, remembering that the film is mainly gelatine, it should be clear that whatever the nature of the surface of the temporary support, the soft glutinous film will take that surface just as we may make the impression of a seal in sealing-wax. The normal carbon print is shiny, due to the gelatine, and so, if as a temporary support we were to use ground glass or matt " opal," the carbon print film would receive the fine granulated surface and give a matted print as a result. This merely by the way as suggesting an additional advantage offered by the double transfer process as a set-off against the slight extra trouble. If double transfer is determined upon, and it is not intended to experiment with ground glass, etc., then when purchasing the carbon tissue, some temporary support (sheets of paper coated with gelatine and shellac) should be procured, also some pieces oi final support. Whatever the temporary support, it must receive an application of waxing solution. This also may be bought, or can be made of : Yellow resin 36 grains. Yellow wax 12 Ether 2 ounces. Melt the wax, add the resin, stir together and then add the ether. Pour a little of this mixture on to the temporary support and spread with a tuft of cotton wool, and rub over to make it even. The final support for double transfer may be pur- chased, and is made ready for use by soaking for ten minutes in alum. The temporary support, after being waxed and the waxing solution having become dry, is to take the place of the single transfer paper in every respect, and the 260 BARNET BOOK OF PHOTOGRAPHY. film developed as already described. When it has reached the final washing, after the alum clearing bath, it is brought into contact with the final support (which has been for ten minutes in alum bath as just described) and is removed to the glass or zinc plate and squeegeed. It is now hung up to dry, and when quite dry the blade of a knife should be inserted at one corner and the temporary support gently pulled off. Such is the carbon process, neither difficult nor lengthy, and with this brief outline to form an introduc- tion, the reader who is a tyro will the better appreciate the fuller description which follows. Whilst the article that follows is more comprehensive than the beginner may require at first, he is nevertheless advised to read it carefully through, and some points which may not seem clear at first will explain themselves after a very little experience. 26l The Carbon Process. colour, therefore little if caused by such general ft5EFORE proceeding to J"* practical details of working, it may be as well to realize what a piece of carbon tissue is, and what takes place in the process of exposing such tissue to light. Air. J. W. Swan, who is to be regarded as the inventor of carbon process as we now know it, was justified in giving the name " tissue " to the film of pigmented bichro- raatized gelatine, as at first it was a tissue unsupported by paper backing and con- taining pigment practically, if not entirely, carbon. The terms " carbon "and " tissue " have been generally accepted as describing a pigmented paper containing permanent any misunderstanding is description. The carbon process, like other kindred methods, is based upon the 262 BAKNET BOOK OF PHOTOGRAPHY. well-known hardening action of light upon a bichromate salt in combination with organic matter. When paper is coated with a mixture of gelatine pigment and a bichromate salt, dried under favourable conditions and exposed to light under a negative it naturally follows that a positive image is produced. The negative acting as a screen, prevents any undue hardening of such portions of the picture as are intended to form the high- lights, only slightly interfering with what are to be the middle tints, and practically permitting full play in the shadows. The latent image is imprinted on and into the film of tissue compound with the most delicate portions on the surface, and means must therefore be adopted to protect the surface during the washing away of all parts of the film not intended or desired to form any part of the finished picture.* In Swan's process this object was secured by cementing the surface of the printed tissue to its temporary support with rubber solution, but after J. R. Johnson discovered that the printed tissue would adhere without any cement to any surface impervious to air and water simply by atmospheric pressure, the same end was gained by soaking the undeveloped print in water until about half saturated, then bringing it into contact under water with either its temporary or permanent support, slightly squeegeeing or sponging to remove as much water as possible without It is generally asserted by non-practical carbon printers that all portions of the film behind that which finally forms the print, are unacted upon by light. That is to say, unchanged and quite as soluble as if not printed at all. The upholders of such a theory should try the following experiment : Take a piece of tissue, cut it through the centre, expose one piece, then mount both under precisely similar conditions and wash in the same warm water bath. Paying special attention to the backing papers, they will find the one unacted upon by light will have parted with its load of coloured material in much less time than the piece that formed the backing of the print. THE CARBON PROCESS. 263 injury to the print ; as to air, there ought not to be any present if care is taken to exclude it before lifting from the water bath. The half-soaked tissue after mounting absorbs every particle of water from between the surfaces, and thus secures optical contact. The squeegee, handy tool as it is, ought to be used with great care, in no case with any degree of force, or serious injury will result, particularly to the finer kinds of work, such as double transfer prints of all kinds, either on paper, ivory or opal. The rubber edge of the squeegee should be free from notches, often caused by contact with the sharp edges of glass plates. The notches can be removed by rubbing on a sheet of glass paper placed on a plane surface. TISSUE MAKING. The tissue compound consists of a mixture of the following ingredients : Gelatine, sugar, pigment and water. The proportions are of infinite variety according to season, the nature of the pigment used, and the purpose for which the tissue is intended. For conveni- ence it is the rule for tissue makers to prepare what is termed stock jelly by dissolving, by the aid of a water bath, gelatine and sugar in water, in varying proportions roughly speaking : Gelatine 2 parts. Water 4 to 7 Sugar* I to ij The pigments are made up into what are termed jelly colours, which are ground either by hand on a slab of glass, marble or granite, using a suitable muller for the purpose, or when large quantities are required a paint mill driven by steam or other power is employed. In *For some purposes (instead of sugar), glycerine, sugar of milk, or treacle may be substituted. 264 BARNET BOOK OF PHOTOGRAPHY. hand grinding the colour is kept moist by syrup on greatly reduced stock jelly. After grinding by hand the pigment is lifted from the slab with a palette knife and stirred into melted stock jelly. When the mill is used, the pigment is mixed with the jelly before grinding. The proportion of pigment to jelly varies enormously according to the nature of the pigment, and may be anything between 2^ per cent, and 25 per cent. Having prepared stock jelly and jelly colours, and allowed both to set, they are weighed out in proper proportions, the jelly being dissolved in a tin vessel placed in a water bath. The colour, generally speaking, is dissolved in a small proportion of the stock jelly placed in the mill and again ground into the bulk of the jelly. In some cases the pigment is dissolved in warm water and filtered through cotton wool, fine felt or flannel. After adding powdered recrystallized bichromate, the jelly compound is ready for coating or spreading on the paper. The coating may be done by hand or machine. Several forms of machine are in use, including the first form invented by Mr. Swan. When only a small quantity is required, it is the general practice to coat by hand. In hand coating, the tissue compound may be strained through fine muslin into a flat tin dish placed on a water bath ; the surface cleared of air bubbles by dragging over it a strip of stiff paper. The sheet of paper to be coated is held in an upright position at the further end of the dish with its bottom edge just touching the surface of the solution, gently lowered until the whole surface of the sheet is in contact with the solution. If the lowering is properly done there will not be any default in contact, but if allowed to rest on the solution a few moments, the presence of air bubbles, if any, will be detected by the presence of little lumps on the back AT THE FOUNTAIN. J. W. WADE. THE CARBON PROCESS. 265 of the paper, these may be removed by raising a corner and touching the spots with a finger tip. The sheet is then raised with a rather slow and steady motion, allowed to drip, then clipped to a line by its top corners and left to dry in a warm dry room from which white light has been excluded. When this method of coating is adopted it is best to have the sheets of paper an inch longer than the dish ; the blank edge prevents contamination of the fingers and distortion of the sheet caused by contraction in drying. Another method of hand-coating is to roll the sheet into a tube shape, placing the roll on the surface of the jelly compound one and a half inches from the top of the free end, raising with rather slow and steady motion as before. When the second method is chosen an oblong and somewhat deep dish will be found better than the flat shape; the flat dish may be used if tilted to give greater depth of solution in a corner. In the manufacture of tissues the greatest care must be taken to avoid over or long-continued heating of the gelatine solution. Either a too high temperature or a lower temperature, long continued, destroys the solution by rendering a considerable portion of it soluble in cold water and to a great degree reducing its gelatinous character. The samples of gelatine used in tissue making are of two kinds, although both of good quality they differ in solubility, in hot weather a larger proportion of the "hard" sample is used, in cold weather vice versa. INSENSITIVE TISSUES. All insensitive tissues are made with a single sample of hard gelatine. They are stocked by dealers and must of necessity be fit for use at any season of the year, to say nothing of those exported to hot climates. 266 BAKNET BOOK OF PHOTOGRAPHY. TRANSFER PAPERS. Papers of many kinds are necessary for single transfer prints, the tint of the paper must blend and harmonize with the tone of the tissue or by contrasting help to produce a pleasing effect:. For prints of warm tones such as red chalk, terra cotta and the various tints of sepia, a yellowish or cream-toned paper forms the most harmonious basis ; the various tints of black, blue, and purple look best on a slightly bluish-tinted paper. For instance, a copy of an old engraving in tissue, of the brown tone of the original would be utterly spoilt by a blue-tinted basis. The above remarks apply only in a limited degree to double transfer papers which in general use are confined almost exclusively to portraiture. Such papers are sometimes modified by tinting mauve, rose, opal, etc., etc. Such tints are only in small demand and are in all cases confined to papers coated with enamel preparations. The best and most durable form of double transfer paper is that prepared on fine chemically pure paper with colourless gelatine and made insoluble by the smallest possible quantity of chrome alum, entirely without white or tinted pigment of any kind. The best variety of double transfer paper only differs from the finest form of single transfer paper in having on its surface a rather thicker and softer coating of colourless gelatine. All transfer papers, either for single or double transfer, may be coated in the same way as tissue, with the exception of those having a very rough surface. Ail drawing papers and in fact all papers of very rough surface are prepared by brushing over their surfaces several coatings of a very thin solution of gelatine con- taining a larger proportion of chrome alum or formalin than is used in making ordinary single transfers. A flat camel-hair brush is best for this form of coacing, care must be taken to avoid air bubbles. THE CARBON PROCESS. 267 FLEXIBLE TEMPORARY SUPPORT. Is paper coated with a gelatine solution in the first instance, and after drying, again coated with an aqueous solution of shellac. SENSITIZING THE TISSUE. Pour the bichromate solution into a deep flat dish (porcelain, ebonite, zinc, wood or tin) to the depth of half an inch to an inch ; place a sheet of tissue in it face upwards, remove air-bubbles with a camel-hair brush or soft sponge, using as little pressure as may be ; turn the sheet and remove bubbles formed on the paper, turn the sheet again face upwards, and passing brush or sponge gently over the surface, keep it evenly wet until it is fairly limp ; remove from the solution, place face down- wards on a perfectly clean glass or zinc plate, squeegee to remove excess of solution, blot or wipe with a soft cloth, remove any solution from the fingers, lift from the plate, handle by edges only, clip to a line, small sizes by one corner only, larger sheets by two corners, leaving a little slackness between the two clips to allow for con- traction in drying, otherwise the sheet will be distorted and difficult to press into contact with the negative. The sensitizing may be done in ordinary daylight. The drying must take place in a room from which aclinic light is excluded, and in a current of warm dry air, free from impurities, such as the products of combustion from burning gas, or an escape of sewer gas, etc., and at a temperature not higher than I2OF. The drying should be done as quickly as possible, otherwise the tissue's keeping property will be greatly reduced, and in all probability a thin film formed on the surface, of insoluble gelatine, known to printers as " decomposed tint," degrading the high-lights, and, except in the case of very " hard " negatives, spoiling the work. 268 BARNET BOOK OF PHOTOGRAPHY. It will be evident to anyone that the fancy forms of sensitizing have been carefully avoided floating on the back, floating on the face, etc., etc. All the results desired can be obtained by immersion. If a hard negative has to be dealt with, a stronger solution, or longer soaking in the bichromate solution, is all that is needed ; for weak negatives vice versa. Note. In the dry frosty air of winter, sensitized tissue will dry without heat, and continue soluble for a considerable length of time, often as long as a month, or even longer. In hot weather it is recommended that the solution of recrystallized bichromate be made immediately before using, as in dissolving the crystals a considerable reduc- tion of temperature is produced. Should the temperature then be over 60 F., ice must be used, not in the solution, but roughly broken up and mixed with salt in an outer vessel. If ice is placed in the bichromate bath allowance must be made by keeping out part of the water. The ice should be encased in several thicknesses of fine muslin to prevent the solid impurities it generally con- tains getting into the solution. When recrystallized bichromate is not procurable, a few drops of liquid ammonia added to solution of crude bichromate is recom- mended. As bichromate is cheap, a fresh solution should be made for each large batch of tissue. PRINTING THE NEGATIVE. Any negative that will yield a thoroughly good albumen print is suitable for carbon work. The thinner negatives now made for P.O. P. and similar processes are less satisfactory for direct prints in carbon, for enlarge- ments and reproductions such negatives can be made to yield most satisfactory results by modifying the trans- parency and the enlarged or reproduced negative. The THE CARBON PROCESS. 269 latitude in this direction is great. No matter how flat the original negative may be, if all the grades are present it can be manipulated in such a way that the most brilliant result will be produced. PREPARATION OF THE NEGATIVE FOR PRINTING. The negative is prepared for printing as in all other processes by removing all defects such #s pin-holes, streaks, etc. For the carbon process the negative requires to be further provided with what is termed a "safe edge ;" this is a line of black varnish, from one-eighth to half an inch in width according to the sizes of the negatives, painted on its margin, either on the film or glass side. In the case of original negatives masks of opaque paper are used instead of the painted edge, the masks having openings cut in them slightly less than the size of the negative. The purpose of the safe edge is to secure a margin on which light has not acted, as such a margin gives greater freedom to the operator in the process of development by preventing the more deeply printed portions of the picture leaving the support when the backing paper is removed. DOUBLE TRANSFER PRINTING. It may be explained in a few words why an ordinary (non-reversed) negative must be printed by double transfer. In all other solar processes when the print is removed from or taken off the face of the negative, it is turned over to view, it therefore follows that the details on the left side of the negative are found on the right side of the positive print ; with the carbon print no such turning occurs, it is mounted upon its support in the same position as it lay on the negative, developed in that position from the back and leaving the position of objects 270 BARNET BOOK OF PHOTOGRAPHY. the same as in the negative. In some cases this reversal of the position of details is unimportant. We will first consider the double transfer. In all double transfer processes a temporary support must be provided. Such supports are of two kinds, flexible and rigid. When a matt-surface print on paper is required, finely grained opal glass is used. For the enamelled surface patent plate, for intermediate or only slightly glazed surface, a flexible support is used. Flexible support yields a surface similar to an albumen print without special preparation. When the higher glaze of the double-albumenized print is desired, the printed tissue is coated with thin collodion before mounting on the flexible support. Rigid supports, zinc or ground-glass plates, have been used, but owing to the difficulty of seeing the details during development their use is practically discontinued. Flexible temporary support is always used in transferring to canvas, wood panel, opal, ivory, etc., etc. In the case of canvas, the double transfer process has two great advantages. First, staining is avoided, the bichromate has been thoroughly got rid of in the process of development. Secondly, the canvas is .prepared to receive the print by a substratum that allows the carbon image to expand and contract with the expansion or contraction of the canvas and not in opposition to it. There are also two advantages in adopting the double transfer process for the production of pictures on ivory. The first, is freedom from bichromate stains. Secondly, the ivory is not distorted by washing in hot water, such distortion generally takes place when the single transfer process is adopted. Wood panels are prepared in a similar way to canvas. Stains are avoided, and as there is not the expansion and contraction of canvas to provide against, the substratum is modified in composition and greatly reduced. The stains above THE CARBON PROCESS. 2yi alluded to are caused by the chemical combination of bichromate with the lead of the paint, forming chromate of lead or chrome yellow. In the case of opal, opaque celluloid, and similar substances, no staining takes place, the double transfer is only required to restore the image to its proper position. SINGLE TRANSFER. The single transfer process is practically the only method in use when large sizes or large numbers of prints are required. For large sizes the negatives are reversed in the process of enlargement. For small sizes one or more reproduced reversed negatives are made, either in the camera from a carbon transparency, or by contact printing from a carbon transparency on a dry plate. With reasonable care, little if any loss of quality occurs in reproduction. As the single transfer process is the most simple form of carbon printing, it is generally recommended to beginners. Probably the most simple form of all is single transfer on opal. The opal plate does not require any preparation beyond cleaning Neither soap nor grease of any kind must be permittee to contaminate the surface, otherwise the print will fail to adhere. Opal plates are cleaned by scrubbing with fine graining sand and water, and a muller or a small plate, either of ordinary or opal glass, placed upon the wetted sand and moved over the surface with a circular motion until soiled or discoloured markings are ground off. THE ACTINOMETER. An aclinometer must be used to gauge the amount of exposure, as only a faint image, and in some tissues none at all, is visible during or after exposure. The simplest form of instrument is the best. That in general use is known as Johnson's Actinometer, a square tin box 272 BARNET BOOK OF PHOTOGRAPHY. containing a long strip of sensitive albumen paper, and provided with a glass lid painted to the colour of printed albumen paper, an opening in the paint in the form of a slit three-sixteenths of an inch in width, from which the paint has been removed. The strip of sensitive paper is made to pass between the top of an inner lid and the painted side of the glass lid underneath the clear slit with the end of the strip protruding at one side of the box. On exposure to light the sensitive silver paper gradually discolours until it closely resembles the colour of the paint, that is called one tint ; the tint is changed by pulling the slip forward just the width of the slit, and so on until the requisite number of tints have been printed for the strongest or densest negative in the batch exposed, those negatives requiring less exposure are turned down or removed when the requisite number of tints are registered in each case. EXPOSURE. For double transfer from opal the materials required are opal plates, sensitive tissue, French chalk, collodion, double transfer paper, pressure frame, flat camel-hair brush, chamois leather. Before placing the negative in pressure frame, carefully clean from both sides all finger marks, etc., with the leather, place negative in frame on a paper mask, or provided with a safe edge. After exposure to light, remove from frame and develop on plate prepared as follows : Rub the whole surface with French chalk on a pad of muslin, afterwards removing loose particles by gentle brushing. Coat with collodion made as follows : Enamel collodion, i part ; ether, i part ; alcohol, i part. Filter and coat by pouring a pool on centre of the plate, and, by tilting it, force the collodion to flow into the top right corner, then to the left, then to bottom left, and finally drain off at bottom THE CARBON PROCESS. 273 right corner, rocking the plate the while. The collodion must be allowed to set until it will bear the gentle pressure of a finger in its thickest part, but must not be permitted to dry in any part before plunging into clean cold water to remove the solvents by washing. The time required in washing is variable according to time of year. When the collodion ceases to repel water it is ready to receive the printed tissue. Soak the tissue for the requisite time, but not so long as to become quite saturated, bring it into contact with collodionized side of plate, remove to squeegeeing board, place over it a piece of wet rubber cloth, or a piece of wet thick single transfer paper, coated side up, to prevent injury to exposed margin of collodion and to facilitate the smooth passage of squeegee over the surface in removing excess of water. If, on removing the covering from the plate, the back of tissue is found to be unevenly wet, blot or place plate in a rack to drain ; in a few minutes develop in warm water, temperature 90 to iooF. Be careful to remove the backing paper under water, and as soon as possible after immersion in the warm bath. Finish develop- ment by laving or pouring warm water over the print from jug or other vessel, until all details are brought out. When washing is finished the print should look rather light', as in drying a decided increase in strength is obtained ; rinse slightly in alum solution to stop bleeding only, place in clean cold water to wash out any remains of bichromate, thoroughly rinse by dashing water upon the print to remove any particles of solid matter that may have stuck to its surface ; place in a rack to dry, and transfer as soon after drying as possible. The transfer paper is cut a trifle larger than the net size of the print, but less than the opal support ; it is soaked in warm water until the surface is slimy to the touch, but not soft enough to break under pressure between finger 274 BARNET BOOK OF PHOTOGRAPHY. and thumb. The softened transfer paper is placed in clean cold water into which the dry print is plunged, water dashed upon its surface to remove air ; the two surfaces are brought into contact under water, and squeegeed into contact as in first mounting before development. When thoroughly dry, the print may be removed from the opal plate by inserting the point of a knife at the edge. Double transfer prints with enamelled surface are produced precisely as above, only substituting patent plate for ground opal, and by adding a second thickness of paper to the back of the finished print before removal from its temporary support. DOUBLE TRANSFER FROM FLEXIBLE SUPPORT. The flexible temporary support is prepared by waxing. The waxing solutions are : No. i. Benzol I oz. Pure beeswax (natural not bleached) 3 grs. No. 2. Turpentine i oz. Yellow resin 10 grs. After dissolving, mix the two solutions, pour a little of the mixture on fine flannel, rub it over so as to evenly moisten the surface of the flexible support, wipe off with a second flannel using only slight pressure but rubbing briskly and with circular motion. When finished, the waxed surface should be perfectly even and quite free from streaks or other markings. The waxing should be done some considerable time before the support is required for use, and exposed to the free action of air to remove all trace of the solvents. THE CARBON PROCESS. 275 PAPER PRINTS WITH ORDINARY OR SLIGHTLY GLAZED SURFACE. After removal from the pressure frame, the tissue, is plunged into cold water with a piece of support slightly larger. After soaking the necessary time, the prepared surfaces are brought into contact under water, removed from the bath and placed upon any even plane surface, such as zinc, glass, etc., squeegeed into contact, blotted or otherwise treated to remove uneven dampness, and developed in warm water as in double transfer from rigid support, then slightly rinsed in alum solution and washed in clean cold water until all traces of bichromate are removed. After the transferring is done as before described, only the print on flexible support must be soaked in water until quite flat before bringing into contact: with its final support. PAPER PRINTS WITH HIGHLY GLAZED SURFACE. The printed tissue after removal from the pressure frame is coated with collodion, for this coating allowance must be made in printing. A considerable reduction in temperature takes place and any moisture present in the air is condensed on the tissue, bringing into action the well-known effect of continued moisture, i.e., considerably increasing the depth of the print. Great care must be taken to coat evenly and to prevent the collodion running in streaks on the back of the print. When such streaks or unevenness of any kind are present, a corresponding dark line or lines will be found on the face of the finished print. Transfer same as for prints with ordinary surface. All prints from flexible support on paper with a highly glazed surface as well as those 276 BARNET BOOK OF PHOTOGRAPHY. intended for transfer to ivory or opal are coated with thin collodion : Enamel collodion 2 parts Ether 4 Alcohol 4 ,. DOUBLE TRANSFER TO OPAL AND IVORY. After development the print is allowed to dry, and as soon after drying as possible it is transferred to its final support, whether opal or ivory, by a solution of gelatine composed of the following ingredients : Gelatine (fairly hard) i^ ozs. Water 20 ,, Chrome alum solution (30 grs.) 2 ,, Soak the gelatine in the water until quite limp, dissolve by heat, then add the 30 grain chrome alum solution ; roughly filter through two or more thicknesses of fine muslin into a flat dish on a water bath. After cutting the print to a size a trifle less than opal or ivory, place both piint and final support in gelatine solution, allow print to stretch until quite flat, then bring them into contact under solution, squeegee and place on edge to dry. When quite dry, remove temporary support by inserting the point of a knife between the surfaces at the edge, wash with benzol or ether to remove all traces of the waxing solution. The print is now ready for the artist. DOUBLE TRANSFER PRINTS ON CANVAS. For double transfer prints on canvas, as a basis for oil painting, there is not at the present moment a large demand. A strong prejudice exists, and deservedly so, against such prints, for the following reasons. Some thirty years ago, in the principal establishment in which carbon work was done, a process of printing on canvas was in vogue. It was roughly this : A stretchiyi artist's canvas without other preparation was coated with dammar varnish ; after drying, the canvas was THE CARBON PROCESS. 277 used in pretty much the same way as single transfer paper is now that is to say, a piece of printed tissue was squeegeed into contact with its surface, developed by floating on hot water, and practically in that crude condition placed in the hands of artists for oil-colour painting or finishing as it is sometimes prudently called. The natural result followed viz., in a dry warm room the canvas stretched, the film of unmodified gelatine contracted ; hence cracks, peeling, etc., until the work, valuable or otherwise, was utterly ruined. The method of preparing the canvas for the reception of the carbon image introduced by the writer is based upon opposite principles, as mentioned in the preceding general remarks, and may be described as follows : A yielding and elastic substratum of gelatine forms a crust, so to speak, that expands and contracts according to the corresponding behaviour of the canvas support. Ordinary painted canvas, such as is used by artists, or strong linen may be used with special treatment. PREPARATION OF PAINTED CANVAS. The canvas is first stretched tightly on a drawing board, same size as picture required, the greater part of paint removed by scrubbing with soda solution (either nail brush, sponge or a piece of flannel will answer the purpose) until the surface of the fabric is exposed and little of the paint remains beyond the priming. After drying, the canvas is coated with the following solution, applied with a flat camel-hair brush. Several coats (three in cold, four in warm weather) are given, drying between each and rubbing with fine sand paper if at all uneven. 2J& BARNET BOOK OF PHOTOGRAPHY. COATING SOLUTION. Cooking gelatine (Cox's soup answers perfeftly) 4 oz. Sugar 2 ,, Glycerine 2 ,, Water 30 ,, 30 grain chrome alum solution i ,, The print is exposed in the ordinary manner, developed on temporary support, allowed to dry and transferred to the canvas as follows: The canvas is placed face upwards, on a level surface by preference, on a broad board over a large tank. The dry print is placed face upwards in a flat dish, the warm coating solution poured over it, air bells removed with the brush, the surface of the canvas brushed over with the solution. The bulk of the solution is then poured on the canvas and before it has had time to run off the print is lowered carefully and quickly upon it and squeegeed to remove excess of solution. After thorough drying, the temporary support is removed, the surface of the print cleaned with benzol or ether or a mixture of both to remove every trace of the waxing compound, and mounted on a stretcher in the usual manner. A print on canvas prepared as above, is perfectly reliable, it will neither crack nor peel, and can be used with perfect confidence as a basis for the most costly form of artistic finishing, as the carbon image rests upon an elastic substratum in actual contact with the fibrous substance of the canvas. TO PREPARE ORDINARY STRONG LINEN OR CALICO. Proceed precisely as for painted canvas (of course without scrubbing), using the same coating solution with half-a-pound white pigment added, sulphate of baryta answers perfectly. Sand or glass paper must be used pretty freely as the surface of the unpainted fabric washes up roughly when the gelatine coatings are applied. THE CARBON PROCESS. 279 WOOD PANELS. Wood panels are prepared by removing the surface of the paint only with soda solution. After drying, a tooth is given by rubbing with fine sand paper and coating with solution as under : Gelatine (Cox's soup) 3 oz. Sugar i Glycerine ,, Water 30 30 grain chrome alum solution f ,, Note. Before transferring to either kinds of canvas or wood panel in cold weather, it is absolutely necessary to thoroughly warm the final support, otherwise the gelatine solution will gelatinize before the excess can be removed from between the surfaces. THE SINGLE TRANSFER PROCESS. The single transfer process may be briefly described as follows : The sensitive tissue is exposed under a negative and the exposure gauged by aclinometer as for double transfer printing. After removal from the pressure frame the printed tissue is plunged into clean cold water along with a piece of transfe paper of any desired surface or quality, cut a little larger than the tissue (to provide a margin by which the picture may be handled without injury during development). After soaking the requisite time, the two prepared surfaces are brought into contact under the water, removed to a squeegeeing board, plate of glass or zinc, and squeegeed into contact ; care must be taken to use only as much pressure as is needed to remove the superfluous water from between the surfaces. A sponge may be used instead of a squeegee, or both may be dispensed with, if care is taken to remove every trace of air from surfaces before lifting from the cold water bath. When neither squeegee or substitute for it is used, the print must be handled with 250 BARNET BOOK OF PHOTOGRAPHY. greater care, as undue bending before atmospheric pressure comes into operation would destroy contact. The print is hung up to drain, and more time allowed between mounting and development. Development is the same as in double transfer, with one or two rather important exceptions, ist. The single transfer print is developed upon the material on which it is to remain. 2nd. There is no preparation of the supports, neither in the case of paper or opal. 3rd. The developed print can be -soaked for a considerable time in a saturated solution of alum without injury, the alum solution greatly assisting in removing bichromate. CARBON TRANSPARENCIES. Carbon transparencies, either for projection, enlarge- ment, or reproduction, are printed in a special tissue known as transparency tissue, and developed on glass plates prepared with a thin coating of fine hard gelatine. The coating solution is composed as follows : Gelatine f oz. Water 40 ,, Bichromate potash i dram. The glass plates are carefully selected, free from bells, scratches, and other defects ; thoroughly cleaned, either by acid or rubbing with plate powder to remove every trace of grease, and then coated with the gelatine solution, and placed in a rack to dry ; when dry, exposed to light to render the film somewhat insoluble. It is not desirable to print until the film is absolutely hardened throughout. The print adheres firmly to the plate when the substratum is not over-printed. A positive intended for projection should show clear glass in the highest lights without undue density in the shadows, all details plainly seen in a word, quite transparent. THE CARBON PROCESS. 2&I Positives intended for enlargement must be fully exposed that is to say, every detail on the highest lights brought out, but no more ; beyond that point there is nothing to be gained. Over-printing in the transparency tends to bury detail in the shadows of the enlarged negative, and to blend the highest grades in the high- lights, reducing the roundness or modelling of the picture. In the case of very hard negatives intended for enlargement, the usual treatment is to sun the whole surface of the transparency in order to secure detail in the high-lights. A moment's consideration will convince any practical printer that nothing but injury to the final print can result from such treatment of the transparency. The high-lights are degraded, the details in the shadows further buried. The better method is to make an extra special transparency tissue, for the printing of such hard negatives, containing a greatly reduced proportion of pigment to gelatine. Such a tissue permits greater depth of printing, retains all details in the shadows and high-lights, and, in fact, enables the enlarger to produce a negative that will yield a thoroughly satisfactory print. REPRODUCED NEGATIVES. 'In making reproduced negatives from hard originals, ordinary transparency tissue will serve every purpose. The transparency is printed in the usual way, and developed on a prepared glass plate ; when dry a negative is printed from the transparency without special treatment and also developed on glass, when a decided reduction of density will be found to have taken place. The repro- duced negative will possess all the good qualities of the original, plus improved printing quality. It is only in the case of extremely hard negatives that the extra special tissue is required. 282 BARNET BOOK OF PHOTOGRAPHY. f If a perfect reproduction of an original negative is required, the transparency must be printed either in very weak light or in direct sunlight. Either method gives a brighter image than that produced in ordinary diffused daylight. The same method must be adopted in printing the negative. Note. Care must be taken when direct sunlight is used to see that the pressure frame and everything in and about it is thoroughly dry, otherwise the tissue may stick to the negative, spoiling the print and probably the negative also. It must also be noted that two tints, printed in direct sunlight, although of apparently the same depth, mean quite as much as three such tints printed in diffused light. FAILURES AND DEFECTS : THEIR CAUSES AND CURE. As a rule, failures in working the carbon process are caused, as in most other cases of failure, by imperfect knowledge of the substances and nature of the ingredients used in the process. Before going into further detail, it may be as well to point out that a great deal of misunderstanding has been caused, by writers on this subject that may be fairly termed " blind leaders of the blind." With only slight knowledge of the subject they have misled beginners by assuring them that the process is simplicity itself, in fact the most simple photo- graphic printing process extant. Up to a certain point, and to that certain point only, is such description true. There are no subtle chemical combinations, no mixing and maturing of toning or other solutions. But and in this case there is great virtue in the but the greatest care is not only required, it is absolutely demanded, in manipulation. A carbon print from start to finish is probably subject to more chances of injury than any THE CARBON PROCESS. 283 other form of print in existence. When this fact has been fully grasped by the novice, and he has been thoroughly prepared for the difficulties before him, the rest is plain sailing. Care, and care only ; nothing beyond. He who wishes to succeed in carbon work must pay infinite attention to every small matter of detail as far as such detail relates to manipulation, other- wise he will only succeed in achieving failure. FRILLING AND RETICULATIONS. Frilly reticulations are generally caused by over- soaking the tissue before development, or failing to provide protection of the clear portions of the margin of the negative by a safe edge. SPOTS ON THE FINISHED PRINT. Spots are generally caused by solid particles of grit or other impurities being allowed to find their way into the water in the process of development, or, as in the case of certain peculiar circular spots that often deface the carbon print, such spots are caused by small fragments of tissue broken from the edges in cutting, which, being of the same colour as the prepared surface of the. tissue and exceedingly small, often escape notice. They adhere most -tenaciously to the surface of the tissue, and if not removed before the print is mounted upon its temporary or final support, cause the mischief referred to ; being confined between two surfaces they cannot escape, but are dissolved by the water used in developing the print, swell and make a circular patch, often greatly injuring the picture. Spots of a different character are produced in quite an opposite direction. Instead of being black they are light, in groups each spot having a dark rim on the outside. They generally occur in under- 284 BARNET BOOK OF PHOTOGRAPHY. exposed prints, and are formed by fine particles of air imprisoned between the coating of gelatine and the paper support. When the tissue is mounted for development and placed in warm water, the fine particles of air swell, and not being able to escape from between the surfaces, impress themselves into the yielding portions of the printed tissue and make the marks above referred to, unless the printing has been deep enough to allow of their removal before development is completed. CAUSE OF FAILURES IN THE SECOND TRANSFER. Other causes of failure refer particularly to prints by double transfer, either to paper, opal, ivory, canvas or wood panel or any similar surfaces. Such failures are generally produced by soap, fat, or any kind of greasy substances being permitted to find their way into the water in which such prints have been manipulated previous to their final transfer. Another point should be mentioned : the sooner a print intended for second transfer is finished the better the result will be. PRESSURE MARKS. Pressure marks are caused by using damp tissue or damp pads in the pressure frame. It is recommended that a piece of waterproof material, such as mackintosh cloth, be placed between the tissue and the padding, and that the pads be as smooth and free from grain as possible. It will be found on close examination that the mottled, spotty appearance, known as pressure marks, closely resemble the texture of the pads behind the tissue. Thos. S. Skelton. INDEX. A. PAGE PAGE Carbon Process, Negative for 255 Alpine ^holography 9 Outfit tor 9 Transfer Paper for, 266 256 Temporary Support.. 258 Lens for to in Detail 261 '.! Carrying camera in 12 Plates for 14 ,, Squeegee for 263 Stock Jelly 163 Carrying Baggage for 15 Outfit for Developing 16 Exposures 17 Development 18 Formulae 20 Coating Paper for 264 Transfer Papers for . . 266 Flexible Support 267 Sensitizing Tissue for 267 Drying Tissue ag Light (tables) 21,22 Accelerator 24 Mum Bath, Formula 41 Negative for 208 Reasons for Transfer 269 Transfer to Opal 271 Aberration, Spherical 60 Aftinometer 271 Chromatic 61 / sugmatism 62 / planat Lens "4 i stgmat Lens "4 / pe-ture of Lens 68 /ngleof Image 7 Accessories in Ponraiiurj 79 Exposure 272 Transfer from Opal . . 272 Tsfer. from Flex. Spt. 274 Glazed Surface Prints 275 Transfer to Ivory 276 ,. Transfer to Canvas 276 Preparation of Canvas 277 Architectural Photography 117 ,i Linen 278 Wood 279 Lenses for 119 Single Transfer .. .. 289 Plates for 122 Transparencies by . . 280 Adlinuuietcr for Platinotype 208 for Carbon Process . . 271 Reproduced Negs. by 281 Failures and Defetts 282 Frilling of Print 283 B. Spots.etc 283 Pressure Marks. ... 284 Backing Mixtures 49 Canvas, Carbon Prints on 276 Background in Ponraituiv 78 Breadth in Pictorial Work 93 D. Blisters on P.O.P 194 Development 23 Bromide Printing 225 Dishes for 25 Safe light kr 226 Negative for 227 Efleft of Temperature di 28 Light for Developing Room 28 Bromide Paper, sensitive side of. . 227 ,, with Pyro-Ammonia 29 ., Printing 232,233,227 Lamp for 228 with Pyro-Soda 33 Bromide Printing, masks and discs 230 Vignettirg .... 231 Formulae 34 with Ortol, Formulae 35 Cloud Printing 231 Bromide Paper, development of . . 233 Iron developer for 234 with Hydroquinone (Quinol) 36 ,, ,, Formulas 36 with Ferrous Oxalate 36 Metol 235 Formula; 37 ,. Hydrokinone for 236 ., Eikonogenfor.... 236 Clearing Bath 235 .. Fixing Bath 235 Drying Plates 41 Dark Room Light, Testing 44 Defefts of Negative 43 Dallmeyer's Portrait Lens 64 Broii. iae Kints, toning with gold 237 Toning with Uranium 238 ., Intensifying 238 Stigmatic Lens 65 Depth of Definition (Focus) . .. 71 Distortion of Lens 72 Reducing 239 Cheap Trajs for 240 Development of Portrait Nega.uo 81 Formulae 83 Detail in Pictorial Work no, 93 C. Development in Hand Cam. Exps. 137 Formula 138 Camera, Carrying in Alps 12 of Lantern bibles 149, 147 Caramel for Backing 49 Curvature of Field of Lens 62 ',', of Enlargements 168 of P.O.P 188 Cooke Lens 65 Composition in Pictorial Work . . 95 Clearing Bath for Platinotype 203, 218 Cloud Printing on Bromide Paper 231 " Platinotype l j ,, 214 Toning 223 Bromide Devlping., Iron.'Henry) 234 Clearing 235 Lens for Piaorial VVoik 113 for Architectural Work 120 Levels 121 Lens for Hand Camera 133 Lantern Slides 141 Various Processes. . 143 Camera for Making 14^ Exposure of 146 Development, . . 147, 149 ,, Warm Tones oil 148, 152 ,, Reducer for 153 Intensifier for 153 28 7 PAGE Linen, Prints on by Carbon Process 278 M. Mountain Photography see Alpine do. Monocles 75 Moving Objefts & Architeftl.Work 129 Mounting POP 187 P GE Platinotype, Print'g. with AcYmeter. 07 Temperature of Develmt. 12 Developing Salts 13 Papers, various kinds 14 Sepia Paper 15 N. Negative Making 23 Devpmt. by Glyc. method 21 Negative for 22 ,, Washing 39 ,. Drying 40 ., Defefts of the 43 Prints Toning 23 Printing Bromide Paper, 232, 233 27 Papers for Gum-Bichro. Process. . 43 P ,, Image too Flat 44 ,, Image too Dense 44 .. Fog on 44 ,. Green Fog on . . 45 ., Black Spots, Marks, Bands on 46 ,. Transput. Bands, Spots on 47 ,, Stains on 47 ., to Intensify 51 Restrainer or Retarder 24 Reducer 24 Reduction of negative 49 ,, Formulae 50, 51 Reduction, local 50 Refraaion of Light 60 RapidReailinear,Symmetrical,I.ens64 Rapidity of Lens 63 ., to Varnish 54 ., for Platinotype 222 for Bromide Printing 227 Reprodn.by Carbon Process 281 ,, for Carbon Printing 268, 255 O. Optics see Lenses 57 Retouching Portrait Negative 83 Reducer for Lantern Slides 153 Reducing P.O.P 192 Reducing Bromide Prints 239 Reticulation of Carbon Prints 283 Reproduction of Neg. by Car. Pro. 281 Preservative 25 Stigmatic Lens of Dallmeyer 69 Stops, Value of 69 <-, R* ' , , P ' ' Planar Lens of Zeiss 65 Pinhole Table of Exposures 75 Portraiture 77 , , Shutter for 77 ,, in Ordinary Rooms . . 79 Portraits Out-of- Doors 80 Portraiture, Lenses for 80 Development in 81 Formulae 83 Piaorial Photography 87 Plates for Architeftural Work 122 P.O.P.. Print-out Paper 177 ,. Care of the Paper 178 Seleaion in Piaorial Work 95 Shutter for Hand Camera 134 Stains on P.O.P 193, 195 Sepia Platinotype 215 Spots on Carbon Prints 283 Single Transfer Carbon Process.. 289 Safe Edge for Carbon Printing 255, 269 Sensitizing Carbon Tissue 267 T. Tripod on Ice, a caution 14 Test for Hypo 40 Testing Dark-room Light Tele-photo Lens 70 ., Washing 179 Truth in Piaorial Photograph 91 Toning 180 Fixing 183 Combined Bath for 184 ,, Alum Bath for 184 Drying 185 Toning P.O.P 180, 189, 191 Tinting P.O.P 194 Toning Platinotypes 2^5, 224 Toning Bromide Prints (gold) 237 Glazing 186, 185 Matt Surface 185 Trays for Bromide Printing 240 Transparency by Carbon Process 280 1 ster.raper tor Carbon r cess. 250, 200 Platinum Toning 189 Toning with Gold & Platnm. 191 Intensifying 191 Reducing 192 TABLES : Light 21 22 ,, Blisters 194 Tinting 194 ,, Hardening 195 View Finder 13 Varnishing Negatives 54 Printing P.O.P 178 Platinotype Printing 197 Paper to Preserve 199 Outline of Process 201 Development 220, 204 Exposure of 206. 202 Washing Plates after Development 38 Wood, Carbon Prints on 279 Zeiss-Planar Lens 65 Lens for Architefture 120 TWELVE PERFECT PRODUCTIONS. Ordinary - = Plates Studio Extra Rapid ,, Rocket Lantern Photo-Mechanical Astronomical Plat|nOjatt_ Bromide Paper Ordinary Bromide Paper Snow Enamel Paper PM Carbon Tissue Price List on application Manufadured by ELLIOTT & SON, ..BARNET. UNIVERSITY OF CALIFORNIA LIBRARY Los Angeles This book is DUE on the last date stamped below. Form L9-Series 4939 I S % '4 3 1 I OF'CAUFOfy^ - S i f= == i 5 ^.OF-CALIFO% ASUIBRARYOc ^E-UBRARYQr ^EUNIVER% ^IDS-AMI 'UU3IIVJ 3VJ n & AA 001 036 960 1 ^ "- -M^ J