Sensitive Plates, Films And Papers
SENSITIVE PLATES, FILMS AND PAPERS Sensitive Dry Plates. A special feature of modern photography is the use of trustworthy ready-prepared sensitive dry plates and films in different grades of sensitiveness, so that there is iu. necessity for the photographer to prepare his own plates, nor, indeed, could he do so with any advantage. The practice of outdoor and studio photography has thus been very greatly simplified; and although with wet collodion there was the advantage of seeing the results at once and retaking a picture if necessary, the uncertainties connected with the use of the silver bath and collodion, and the amount of cumbrous apparatus necessary for preparing and developing the plates, far outweighed it. There is also an enormous saving of time, in using dry plates as compared with wet, by deferring development. In tropical climates, also, dry plates can be used when work with wet plates would be impossible. On the other hand, the uncertainty of more or less random exposures on readyprepared elates must not be overlooked. Besides their use in taking negatives, gelatin dry plates are also largely used for printing transparencies, lantern slides, enlargements, etc. For negative work they are prepared with an emulsion in gelatin of silver bromide, alone or with the additjon of silver iodide or chloride, and are to be obtained in five or six degrees of rapidity: " slow," for photomechanical or "process" work; "ordinary," for general purposes when quick exposures are not required; "rapid, for landscape and portraits; "extra rapid," for instantaneous exposures; and " double extra rapid," for very quick snapshot work in dull weather or for special subjects. These latter kinds are exceedingly sensitive, and require great care in use to avoid fog. In order to prevent halation, or irregular action by reflection from the back surface of the glass, dry plates are coated with a non-actinic " backing," which can easily be removed before development.
Self-developing dry plates were introduced in 1906, in which the developing agent is mixed in the film itself, as in the Ilford " Amauto " plate, which only requires immersion in a solution of washing soda for development, or, as in the Wellington " Watalu " plates, applied on the back of the plate, plain water only being required for development, this application also preventing halation. The slow plates used for printing lantern slides and transparencies are usually prepared with an emulsion of silver chloride with ot without free silver nitrate and other haloids.
The rendering of photographic plates isochromatic or sensitive to all colours by dyeing them with eosin, or other suitable dyes, has been greatly improved by the use of new dyes, especially those of the isocyamn group, prepared by Dr E. Konig of the Hoechst factory, and known as orthochrom T," " dicyanin," "pinaverdol," " pinachrom " and " pinacyanol," the" latter of which can confer on a silver bromide plate as high a degree of sensitiveness for red as erythrosin does for yellow; also F. Bayer's " Homocol," Dr A. Miethe's " ethyl red," and other similar dyes (see E. Jb., 1905, pp. 183, 336). Panchromatic plates are now largely manufactured and used for all photographic work in which a true rendering of the relative colour luminosities is essential, and more particularly for the various methods of colour reproduction in which plates are required to be sensitive to red, green and blueviolet. They are made in different degrees of general and colour sensitiveness, according to the purpose for which they are required, the ordinary " isochromatic " being most sensitive for yellow and green, and the " panchromatic " for red, orange and yellow, as well as for green, blue and violet. To obtain the best results from all these plates it is necessary to screen off the blue and violet rays with yellow or orange transparent screens, or colour filters, made of coloured glass, or glass coated with coloured gelatin, collodion, etc., or with glass cells containing solutions of suitable dyes or salts. For the various processes of three-colour reproduction panchromatic plates and special red, green and blue-violet filters have to be used for taking the three negatives, their intensities and absorptions being carefully adjusted to the particular plates in use; the same applies, but jess strictly, to the yellow screens used with ordinary isochromatic plates. Dyes specially suitable for these colour-filters have been prepared by Dr E. Konig. Various kinds of colour screens for ordinary, microscopic and trichromatic work are made commercially, and Messrs Schott of Jena make a special yellow glass in three tints for the purpose.
Plates for Colour Photography. In 1868 Louis Ducos du Hauron, among various trichromatic methods patented for photographically reproducing coloured objects in the colours of nature, described one in whicli the trichromatic principle, instead of being carried out on three separate plates, was to be combined in one plate by means of a transparent medium covered by a trichromatic screen divided into narrow juxtaposed lines or minute spaces, corresponding tc the three primary colours, red, green and blue-violet, the transparent colour of each of these lines or spaces acting as a colour filter. A sensitive panchromatic plate was to be exposed in contact with this screen to produce a negative with lines or spot! corresponding to the relative strength of the three coloured lights passing through it, so that a diapositive print on glass properly registered with the tricolour screen would show the object in its proper colours. This method could not be carried out successfully for want of efficient panchromatic plates and other difficulties.
Between 1892 and 1898 several patents were taken out by I. W. McDonough and J. Joly for various methods of preparing trichromatic ruled screens (Ph. Journ., 1900, p. 191). The Joly method was fairly successful in action, but had several disadvantages owing to the coarseness of the lines, the necessity for having two screens, one for taking and another for viewing, and the cost of making them (B. J. A., 1899, p. 671). The "Florence" chromatic plate (I9 O 5), worked out in America by J. H. Powrie and Florence M. Warner, was an improvement on the Joly method, the colour screen being photographically printed on a glass plate, coated with panchromatic emulsion and exposed to the coloured object through the screen (Penrose Pictorial Annual, 1905-1906, p. in). Some good results were produced, but it has not come into use.
After several years of laborious research, Messrs Lumifire, of Lyons, adopting Ducos du Hauron's coloured grain method, succeeded where he had failed, and in 1907 brought out their " Autochrome " plates, in a very complete and practical form, making it possible to produce photographs in the colour of natural objects by one exposure instead of three, as in the ordinary three-colour processes. Glass plates are coated with an adhesive medium over which is spread a mixture of potato starch grains, of microscopic fineness, stained violet, green and orange, the interstices being filled in with fine carbon powder to form a tricolour screen, dark by reflected and of a pinkish, pearly appearance by transmitted light. This is varnished and coated with a thin sensitive panchromatic emulsion of gelatino-silver bromide. The plates are exposed in the camera from the back, through the tricolour films, using also a special compensating orange-yellow screen, before or behind the lens, then developed as usual, producing a negative coloured image in the complementary colours, which is then treated and reversed so as to produce a positive coloured image by transmission, showing the picture in its proper colours. The results thus obtained are remarkably good and practically solve the problem of direct colour photography in a simple and fairly inexpensive manner (see Agenda Lumikre, 1909).
In C. L. Finlay's " Thames " colour plate (1908) the tricolour screen is formed by rows of circular dots coloured alternately orange-red and green and the intermediate spaces blue. It is used alone, the coated surface being placed in contact with a panchromatic plate, the uncoated side towards the lens. It carries register marks for adjusting it to the finished picture after development and reversal of the image. These screens, being more transparent than the " Autochrome," require less exposure, but the colour rendering is not so perfect. In the Jougla " Omnicolore " plate (1909) the tricolour screen and sensitive surface are combined on one plate as in the " Autochrome," but the screen is made up of a series of blue-violet parallel lines, with intermediate alternate broken 'lines of orange-red and yellowish-green at right angles to them, the red narrower than the green. The relative sizes of the coloured dots in the three plates are approximately :
8 J 5 ,, " Autochrome " starch grains . -^fa to " Thames " plate, dots, diameter . " Omnicolore " plates, blue line . red square .
E. Fenske's " Aurora " plate (1909) is a tricolour screen formed by coating a glass plate with a mixture of finely divided particles of gelatin, dyed orange-red, green and blue-violet, without any intervening spaces. The grain generally is coarser and more irregular than in the " Autochrome " plates, but optically corresponds more closely to them than the " Thames " or " Omnicolore " screens do. These plates are issued uncoated for use with any suitable panchromatic plate. A later process is due to Dufay. With the exception of the " Autochrome," these processes are still more or less in the experimental stage.
Celluloid Films. In order to avoid the weight of glass plates, which may become burdensome on a tour, and also the risk of breakage of valuable records, thin films or sheets of celluloid coated with sensitive emulsions can be used, with great saving of bulk and weight and no loss of efficiency, though such films are sometimes liable to deterioration by long keeping before or after exposure. They are made in two thicknesses, stiff or flexible, the stiff being used exactly as plates, but held in a carrier or simply backed with a card or glass plate, while the flexible are made up in separate sheaths with cardboard backing, as in the " Kodoid ' films, or in convenient packages of twelve or more in " fijm packs " of various patterns. Flexible films of this kind on celluloid have for many years past also been prepared in long strips of different widths suitable for use in hand cameras of the Kodak types and in roll-holders. In the early forms of roll-holders the films were used alone, and being unprotected had to be changed in the dark room, but, as already stated, they are now supplied on spools in cartridges which can be changed in daylight. C. Silvy seems to have been the first to employ this method in 1870. In these cartridges the film is attached to a much longer strip of black paper, and rolled up with it, so that several turns of the paper have to be unrolled before the film is ready for exposure, this point being marked on the outside paper for the successive exposures, with numbers visible through a red screen at the back of the holder. When all have been exposed, the black paper is rolled on for several turns, and when taken out of the holder the loose end is fastened up till the film is developed. As these films are principally used for landscape work, it is now usual to make them isochromatic, and they may be used with or without a yellow screen. They are also made " non-curling " by being coated with gelatin on both sides. Negatives taken on these thin films have the advantage that they can be printed from either side without perceptible loss of definition, which is useful in printing by the single transfer carbon process, and in some of the photo-mechanical printing methods. Flexible transparent films in sheets and rolls have also been prepared upon hardened gelatin, but it is difficult to retain the original dimensions of the film owing to expansion of the gelatin. Paper coated with sensitive emulsions has been successfully used for making negatives in the same way as the celluloid films, and is cheaper, but much more liable to deterioration from atmospheric action before and after exposure, and unless developed soon after exposure the impressed images may fade and become undevelopable. Such papers are, however, still used in meteorological and other self-recording instruments. Stripping films of thin celluloid upon a paper support were introduced by Messrs Wellington and Ward, and had advantages for printing from either side, but are not now made.
Photographic Printing Papers. Part passu with the supply of ready-prepared plates, all kinds of photographic printing papers can now be obtained ready for use, so that the photographer has nothing to do with the preparation of his sensitive plates or papers. The old albuminized papers have been generally superseded by ready-prepared sensitive papers coated by machinery with emulsions of silver haloids in gelatin, with or without citrate or other organic silver salts, the chloride being used for most of the " P.O.P." or " printing out papers," which contain more or less free silver nitrate, and in the " self-toning " papers some salt of gold. Some of these printing out papers are also made with emulsions of silver chloride in collodion, and known as " C.C." or " collodiochloride." The basis of most of the developable bromide papers used for enlargements and direct copying, containing no free silver nitrate, and with which an invisible image is brought out by development, much in the same way as with dry plates, is silver bromide. These papers are made in great variety of tints and surfaces, " smooth " and " rough," " glossy " and " matt," for producing different effects. They are largely used for direct printing by artificial light or daylight, for enlargements, and for printing photographic post-cards, etc., in large numbers by machinery, the prints being made on a long band with an almost instantaneous exposure, and developed and fixed by being passed through the proper solutions on large rollers or otherwise. Papers for the platinotype processes, sensitized with salts of platinum and iron, are also manufactured for printing out entirely or for development with potassic oxalate. Prints on these papers have the advantage of being permanent.
Messrs York Schwartz and J. Mallabar s process of developing and toning prints made on a special sensitive paper prepared with an emulsion of silver phosphate was introduced by Messrs Houghton in 1908 under the name of " Ensyna." Very short exposures to day or artificial light are required, and with a special developer (" Ensynoid ") permanent prints are obtained with a varied scale of tones similar to those given by toning with gold, the colour of the print being determined by the exposure, short exposures giving purple and long exposures brown or reddish tones. The process is a rapid one, the operations of printing, developing, fixing and washing being completed within about ten minutes or even less.
For the various methods of printing in permanent pigments (" Autotype," etc.) tissues are prepared coated with pigmented gelatin in various colours, and very successful results in colour photography have been obtained by printing from suitable negatives in three colours with specially prepared yellow, blue and pink tissues. Similar papers, prepared with pigmented gum instead of gelatin, are used in the " gum bichromate " process, and " single transfer " papers, coated with plain gelatin, are used in the pigment printing processes to receive the developed print, and are also useful for photo-lithography, the new " oil-printing " methods, and in trichromatic printing on paper by the Sanger-Shepherd method and Dr Konig's " Pinatype." For Manly's " Ozotype " and " Ozobrome " processes special gelatinized and pigmented papers are made. " Cyanotype " and " Ferrogallic " papers are prepared for the use of architects, engineers, etc., in rolls of considerable width, for the direct reproduction of tracings and drawings as blue or black prints by these and similar methods.
Apparatus for Development. The recognition of the fact that the two principal factors in the development of modern photographic dry plates with a suitable developer are time and temperature, and also that a prolonged immersion in dilute solutions is in many cases a more convenient and equally efficient method of development, has led to the construction of apparatus for enabling the operation to be carried out almost automatically and for timing its duration.
In 1894 A. Watkins brought out his factorial system of development based on the principle " that with a correct exposure on a given plate with a given developing agent, the time of development required for a given printing opacity has a fixed arithmetical ratio to the time of appearance of the high lights of the image, provided the developing power of the solution remains constant during development; and this rule holds good for all variations of strength, amount of alkali or bromide, and temperature within those limits which have been found safe in practice ' (Photo. News, 1894, 38, pp. 115, 729; and further, Ph. Journ., 1900, 24, p. 221). By a series of observations he ascertained the multiplying factors of most of the developers in ordinary use, and in 1905 brought out his " factorial calculator " and a " dark-room clock " for facilitating the working of the method. The former is made of aluminium, and consists of two circular disks, the upper smaller one rotating and carrying a pointer. The outer disk is marked with a scale of Watkins' factors for the different developers, as given in the " instructions " accompanying the instrument, and is used to denote the " time of development " in minutes. The scale on the inner FIG. 72. Watkins's Factorial FIG. 73. Watkins's Dark- Calculator, room Clock, disk shows the " time of appearance " in seconds or minutes. In use the pointer is set to the factor for the developer in use, and against the " time of appearance " on the inner scale will be found the total number of minutes required for complete development (fig. 72).
The " calculator " can be used with any ordinary clock or watch, but the " dark-room clock " (fig. 73) has been specially constructed for the factorial system. It is an improvement on the earlier forms of Watkins' " Eikronometer," and has a 4 in. dial with 10 minute and 100 seconds divisions, very plain for dark rooms, centre seconds hand, stop action and outside indicator to mark the completed time. The seconds hand completes the revolution in too seconds, while the minute hand does so in 10 minutes, or sufficient for the longest ordinary development, though it runs on, if necessary, very much longer, both hands starting together always at O.
In 1908 Watkins brought out another system of thermodevelopment " by time dependent on the use of a standard " time developer," the duration of the development, at a given temperature, being modified according to the make and speed of the particular plate in use. The temperature variations are indicated by a movable scale, or " thermo-calculator," on the bottle of developer, the variations for development speed of various plates being given approximately on the " Watkins' Plate Speed List, which thus shows the " speed of plate " and " speed of development " with the standard developer at 60. This method is well adapted for plates, films and stand development in tanks or machines, no observation of the plate being required, and the times are most conveniently observed with the " dark-room clock. Full details of these two distinct methods of development will be found in the 4th edition of the Watkins' Manual of Exposure and Development.
C. W. Piper's " photographer's stop clock " (1906) is a more elaborate clock, intended for use not only in " time development " but for all photographic operations in which accurate control in regard to time is of importance. It is fitted with a gong and arranged to work by " time " or " bulb." Once started, by pressure on a lever or on the bulb, it will continue to go until stopped, striking the gong at the completion of every minute, when the seconds hand reaches the zero point. A second pressure on the bulb stops the clock, so long as the pressure is continued, while pressure on a lever stops it permanently. It is thus useful for timing any intermittent operations, whilst the clock adds up the separate times and prevents the occurrence of errors difficult to avoid when timing with an ordinary watch. By an additional attachment a prolonged time exposure with the camera may be terminated, or an " instantaneous " or short " time " exposure given at any prearranged time. Messrs Houghton's " Ensign " clock for time development has a dial with 60 divisions, a single hand, and is fitted with a gong. It can be set to ring an alarm bell at the expiration of any period from one minute to one hour, can be started or stopped immediately and is easily read in the dark-room. _ It requires no winding up, the action of setting providing the tension for the recording movements. It can be stopped and started at will and the bell arranged to give a short or prolonged ring. S. Stanley's is another convenient Torm, with a 4j in. dial, divided into 60 seconds and 60 minutes, the thick hand recording the seconds and the thin hand the minutes.
Several forms of developing tanks and machines have been constructed for developing a number of exposed plates, together with ordinary or dilute developers, with the aid of the factorial system or independently of it. The Kodak " Automatic Developing Tank " (1905) is a useful arrangement by which bands of exposed roll films can be developed in daylight, without any need of a dark-room (fig. 74). The exposed film is wound from the spool FIG. 74. Kodak Developing Tank.
into a rea celluloid apron contained in a box A, then placed in the tank B, where it is left in a dilute developer for about twenty minutes, and requires no attention. It gives very good results. For the " Brownie " films a special daylight developing box is made. With the Kodak " Eastman Plate-developing Tank " (1908) the exposed plates are removed, in the dark-room, from the plate holders and placed, in pairs back to back, in a special framework holding six pairs, which is lowered into a metal tank containing the developer, and is fitted with a watertight lid so that it can be inverted during development. A clock face, with pointer, by which the period of development may be noted is fitted outside the tank. Another apparatus of the kind is made for developing celluloid films exposed in the " Premo Film Packs " (fig. 75).
Other forms are made, and in some the fixing and washing can also be effected. These tanks undoubtedly save much time and trouble in developing a large number of exposed plates or films, and have been found to work with efficiency and regularity. Eastman Kodak Co. brought out in 1907 a machine for developing paper prints on bromide or gaslight papers.
FlC. 75. Premo Film Pack Tank (1908). PHOTOGRAPHIC PRINTING APPARATUS For ordinary printing- purposes pressure frames, with or without glass fronts, are used for holding the negative and sensitive paper in close contact during exposure to light. They are fitted with hinged backs enabling the progress of the printing to be seen. The pressure is usually given with springs or with screws or wedges acting on the back. They are made in different kinds shown in the dealers' catalogues. For copying large tracings and engineers' drawings by the cyanotype and similar processes large glazed frames are used, mounted on a stand with axle, so that they may be easily turned over for refilling or fixed at a suitable angle to the light. The pressure is given by an elastic cushion or vacuum arrangement, by which air is pumped out from under an indiarubber sheet covering the back of the frame, thus securing a perfectly uniform pressure of about 14 Ib to the square inch without strain on the front glass. Such frames are also useful for various photo-mechanical printing processes with large negatives or metal plates.
For rapid printing of post-card and other negatives up to 8JX 6J in. a handy and simple apparatus the " Rapide " has been brought out, consisting of a lantern fitted for oil, gas or electric light, with a sloping front, in which a special printing frame is fixed and arranged so that the prints can be rapidly exposed one after another (B. J. A. 1909), p. 691. In another form arrangements are made for exposing a large number of printing frames on a suitable stand, in one or two tiers round a central arc lamp, which may be provided, as in the " Westminster " revolving printing frame, with a shade to protect the eyes of the operator when examining the prints or changing the frames.
For printing tracings, etc., in long rolls, cylinder and rotatory machines of various types are used, so that the tracing and sensitive paper may be drawn together at a regulated speed in close contact round a glass cylindrical surface within which electric arc or mercury vapour lamps supply the source of light. Several machines of this kind are described in Eder's Jahrbuch for 1908, also in the patent records and photographic journals.
AUTHORITIES. Apparatus in general: Sir W. de W. Abney, Instruction in Photography (nth ed., 1905); R. C. Bayley, The Complete Photographer (1906); Dr J. M. Eder, AusjuhrliCnes Handbuch der Photographic (2nd ed., pt. i. (2), 1892); Jahrbuchcr fur Photographic und Reproductions Technik (E. Jb.), (1887-1908). Valuable for reference on all forms of apparatus: Dr C. Fabre, Traite encyclopedique de photographic (T E. P.) (vol. i., 1889; Supplements A, 1892; B, 1897; C, 1902; D, 1906), also gives much information about photographic apparatus and optics; Chapman Jones, An Introduction to the Science and Practice of Photography (4th ed., 1904); British Journal Photographic Almanacs to 1909 (B. J. A.); Patent Office, Abridgments of Specifications, class 98, " Photography " : Photography Annuals (1891 to 1899) ; Photographic Journal (Ph. Journ.) ; Year Books of Photography to 1907.
Lenses and Optics: C. Beck and A. Andrews, Photographic Lenses (6th ed.); W K. Burton, Optics for Photographers (1891); R. S. Cole, A Treatise on Photographic Optics (1899); T. R. Dallmeyer, Telephotography (1899); J. A. Hodges, Photographic Lenses (1895); Captain Houdaille Sur une methode d'essai scie.ntifique et pratique des objectijs photographiques (1894); G. L. Johnson, Photographic Optics and Colour Photography (1909); O. Lummer, Contributions to Photographic Optics, translated and augmented by Professor S. P. Thompson (1900); Dr A. Miethe, Optiq'M photographique sans devellopements mathematiques , translation by A. Noaillon and V. Hassreidter (1896); Lieut.-Coloncl P. Moessard, L'Optique photographique (1898), L'Objectif photographique (1899); C. W. Piper, A First Book of the Lens (1901); Dr M. von Rohr, Theorie und Geschichte des photographischen Objectivs (1899), a most valuable theoretical and historical summary of photographic optics and its literature; Hans Schmidt, Das Fern-Objectiv im fortrat- Architectur- und Landschaftsfache (1898); Dr H. Schroeder, Die Elemente der photographischen Optik (1891); J. T. Taylor, The Optics of Photography and Photographic Lenses (3rd ed., 1904); The " PhotoMiniature Series," No. I (1899), Modern Lenses, No. 26 (1901), Telephotography; No. 36 (1902), Lens Facts and Helps; No. 79 (1907), The Choice and Use of Photographic Lenses.
Hand Cameras, Shutters, Exposure Meters, etc. : Sir W.de W. Abney, Instantaneous Photography (1895); H. Boursault, Calcul du temps de pose en photographie (1896); W. B. Coventry, The Technics of the Hand Camera (1901), the working principles of lenses, shutters, etc., for instantaneous exposures are treated mathematically and practically; L. David, Die Moment-Photographie (1898); G. de Chapel d'Espinassoux, Traite pratique de la determination du temps de pose (1890) ; Dr R. Kriigener, Die Hand Camera und ihre Anwendung fur die Moment-Photographie (1898); A. Londe, La Photographie instantanee, theorie et pratique (3rd ed., 1897); F. W. Pilditch, Drop-Shutter Photography (1896) ; A. de la Baume Pluvinel, Le Temps de pose (1890); A. Watkins, The Watkins Manual of Exposure and Development (4th ed., 1908). The Practical Photographer, No. 8 (1904), " Hand Camera Work." The " Photo-Miniature Series," No. 3 (1899), Hand Camera Work; No. 37 (1902), Film Photography; No. 56 (1903), The Hurter and Driffield System; No. 76 (1906), The Hand Camera; No. 77 (1907), Focal Plane Photography.
Colour Photography; Agenda Lumiere, La Photographie des couleurs et les plaques autochromes (1909) ; G. E. Brown and C. W. Piper, Colour Photography with the Lumiere Autochrome Plates (1907) ; Baron A. von Hiibl, Three Colour Photography, translated by H. O. Klein (1904); Theorie und Praxis der Farben Photographie mil Autochrom Flatten (1908); G. L. Johnson, Photographic Optics and Colour Photography (1909); Dr E. Konig, Natural Colour Photography (trans, by E. J. Wall (1906) ; Die Autochrom Photographie und die verwandten Dreifarbenraster-verfahren (1908). (J. WA.)
III. PICTORIAL PHOTOGRAPHY Pictorial photography differs from other branches of photographic practice in the motive by which it is prompted. Employing the same methods and tools, it seeks to use photographic processes as a means of personal artistic expression. Thus in the early days of Fox Talbot's calotype, about 1846, David Octavius Hill, a successful Scottish painter, took up this method of portrayal, and, guided by an artist's knowledge and taste, and unfettered by photographic convention, which indeed had then scarcely begun to grow, produced portraits which for genuine pictorial quality have perhaps never been surpassed, especially if some allowance be made for the necessary imperfections of the " Talbotype " (see plate). Whether they were in their day typical examples of Talbotype with all the latest improvements, Hill probably never cared. When, again, a few years later, Sir William J. Newton, the eminent miniature painter, read a paper before the newly formed Photographic Society of Great Britain (now the Royal Photographic Society), his recommendation to depart from the custom of defining everything with excessive sharpness caused his address to be almost epoch-making. " I do not conceive it to be necessary or desirable," he said, " for an artist to represent, or aim at, the attainment of every minute detail, but to endeavour at producing a broad and general effect. ... I do not consider that the whole of the subject should be what is called ' in focus '; on the contrary, I have found in many instances that the object is better obtained by the whole subject being a little out of focus." The doctrine has been persistently repeated ever since, but only within the last decade of the 1pth century was the suppression or diffusion of focus received by photographers generally with anything better than ridicule or contempt, because it was unorthodox. O. G. Rejlander, Mrs Julia Margaret Cameron, H. P. Robinson, and others, by precept or practice, strove against such photographic conventions as had arisen out of those technical exigencies to which pictorial qualities were so often sacrificed. As late as 1868, in the Manual of Photographic Manipulation, by Lake Price, the old advice to arrange a group of persons in crescent form, so as to adapt the subject to the curve of the field of the lens, was repeated with the additional recommendation of plotting out on the ground beforehand the " curve of the focus " as a guide. As a defiance of this dictum, Rejlander, in 1869, produced a group of the members of the Solar Club in which some of the chief figures were set widely out of the " curve of the focus." The mere technical difficulties of this performance with wet collodion plates, and in an ordinary upper room, need not be touched upon here, but it is to be noted as one of those triumphant departures from convention which have marked the progressive stages of pictorial photography. At about the same period, Mrs Cameron, carrying the recommendation of " a little out of focus " rather further, regardless of how her lens was intended to be used by its maker, secured the rendering dictated by her own taste and judgment, with the result that many of her portraits, such as those of Tennyson, Carlyle, etc., are still in their way unsurpassed. Contemporaneously, Adam Salomon, a talented sculptor, " sunned " down the too garish lights of his photographic prints, and strengthened the high lights by working on the back of the negative.
But, during the concluding quarter of the 19th century, probably the most powerful influence in pictorial photography was that of H. P. Robinson, who died in February 1901, and, but for a brief period about the year 1875, was one of the most prolific " picture makers." Inspired by Rejlander, of whom he was a contemporary, Robinson will perhaps be best remembered by his earlier advocacy of combination printing. As early as 1855 Berwick and Annan exhibited a photograph which was the result of printing from more than one negative, a figure from one plate being cunningly introduced into a landscape print from another. Then came from Rejlander " The Two Ways of Life," in which, with wonderful ingenuity, thirty different negatives were combined. Robinson followed, and between 1858 and 1887 exhibited numerous examples of combination-printing, one of the most popular and fairly typical examples being " Carolling " (see plate) , which received a medal in the exhibition of the Royal Photographic Society in 1887.
Though in this combination-printing one may perhaps perceive the germ of incentive towards the production of special effects not seen in the original, yet the practice was not destined to become very popular, for even in the most capable hands there remains the difficulty, if not impossibility, of fitting a portion of one negative into a print from another and still preserving true rela^ve tonality, and even true proportion. Skilfully produced, eminently popular in character though " Carolling " may be, such errors are not absent. Of this combination-printing Dr P. H. Emerson has said: " Cloud printing is the simplest form of combination-printing, and the only one admissible when we are considering artistic work. Rejlander, however, in the early days of photography, tried to make pictures by combinationprinting. This process is really what many of us practised in the nursery, that is, cutting out figures and pasting them into white spaces left for that purpose in the picture-book. With all the ' care in the world the very best artist living could not do this satisfactorily. Nature is so subtle that it is impossible to do this sort of patchwork and represent her. Even if the greater truths be registered, the Jesser truths, still important, cannot be obtained, and the softness of outline is easily lost. The relation of the figure to the landscape can never be truly represented in this manner, for all subtle modelling of the contour of the figure is lost."
Pictorial photography received a large accession of votaries in consequence of the greater facilities offered by the introduction of the gelatino-bromide, or dry-plate, process, which, although dating from 1880, did not notably affect photographic communities until some years afterwards; and although improvement in appliances and instruments had little to do with the advance of the pictorial side of photography, yet, indirectly at least, the dry-plate and the platinotype printing process have had an undoubted effect. The former gave enormously increased facility, and dispensed with tedious manipulations and chemical knowledge, while its increased light-sensitiveness decreased the limitations as to subjects and effects. The platinotype process was discovered in 1874-1880 by W. Willis, who employed his chemical skill and knowledge to give the world a printing process more likely than the hitherto prevalent silver papers to satisfy artistic requirements.
Up to 1882 but few outdoor photographers had ventured to run counter to the general dictum that photographs should only be taken during sunshine or good bright light, and unquestioning consent would have been given everywhere to the proposition that it would be absurd to work when anything like fog or atmospheric haze was present. Isochromatic plates, introduced for the purpose of equalizing the actinic power of various colour luminosities, and so rendering colours in correct relative value, were recommended by one writer, who applauded their supposed advantage of enabling the photographer to photograph distance without any suggestion of atmosphere. That evening or morning haze might enhance the beauty of a landscape, or that the mystery of half-concealment might itself be beautiful, does not seem to have occurred to the photographer, who had become infatuated by the exquisite clearness and sharpness which, with a minimum of labour, he was able to achieve. It is therefore interesting to note one of the first photographic successes which broke away from this convention, just as Rejlander's Solar Club group defied the formula of arranging human figures like the tiers of an amphitheatre. William M'Leish, of Darlington, a Scottish gardener who had taken to photography, and who seems to have been less under the influence, or it may have been that he was ignorant, of the old dicta, sent to the Royal Photographic Society's Exhibition in 1882 a photograph entitled " Misty Morning on the Wear," a very beautiful view of Durham Cathedral as seen through the mist from across the river. The judges, although they that year awarded eleven medals, passed this by; but appreciation came from outside, for newspaper critics, and practically all those who were not blinded by prejudice and conventionality, declared it to be the photograph of the year. The -exhibitions immediately succeeding revealed numerous imitators of M'Leish, and both figure and landscape work began to be shown in which there was evidence of greater freedom and originality.
Meanwhile the Photographic Society of Great Britain had drifted away from its artistic starting-point, and had become chiefly absorbed in purely scientific and technical subjects. But the general apathy which existed in respect of the artistic aspirations of some workers was the forerunner of a period of renaissance which was to end in lifting the pictorial side of photography into a greatly improved position. In 1886 Dr P. H. Emerson read before the Camera Club a paper on " Naturalistic Photography," which served as an introduction to the publication (1887) of his book under that title. Unquestionably this book struck a powerful blow at the many conventionalities which had grown up in the practice of photography; the chief doctrines set forth being the differentiation of focus in different planes, a more complete recognition and truer rendering of " tone," a kind of truthful impressionism derived from a close study and general acquaintance of nature, and a generally higher and more intellectual standard. After the publication of a second edition in 1889 Dr Emerson publicly renounced the views he had published, by issuing in January of 1891 a bitterly worded, black-bordered pamphlet, entitled The Death of Naturalistic Photography. But the thoughts which the book had stirred were not to be stilled by its withdrawal. Towards the end of the same year the conflict which within the Photographic Society had become apparent as -between the pictorial enthusiasts and the older school, culminated in connexion with some matters respecting the hanging of certain photographs at the exhibition of that year; and a number of prominent members resigned their membership as a protest against the lack of sympathy and the insufficient manner in which pictorial work was represented and encouraged. This secession was to prove the most important event in the history of that branch of photography. The secessionists being among the most popular contributors to the annual exhibition gathered round them numerous sympathizers. In the following year they formed themselves into a brotherhood called " The Linked Ring," and in 1893 held their first " Photographic Salon," at the Dudley Gallery, Piccadilly. The most noteworthy of the early adherents attracted to the new body was James Craig Annan, whose work was practically unknown until he exhibited it at the first Salon; and almost at once he, by general consent, took a position amongst pictorial photographers second to none (see plate).
Aroused into greater activity by these events, the Royal Photographic Society began to pay more attention to what had now become the more popular phase. At subsequent exhibitions the technical and scientific work was hung separately from the " Art Section," and a separate set of judges was elected for each section. It became the custom to allot by far the greater amount of space to the " artistic "; and later, artists were elected as judges, by way of encouraging those who were devoted to the pictorial side to send in for exhibition. In the autumn of 1900 the New Gallery was secured, and a comprehensive exhibition of all phases of photography was held.
It is interesting to note that as a distinct movement pictorial photography is essentially of British origin, and this is shown by the manner in which organized photographic bodies in Vienna, Brussels, Paris, St Petersburg, Florence and other European cities, as well as in Philadelphia, Chicago, etc., following the example of London, held exhibitions on exactly similar lines to those of the London Photographic Salon, and invited known British exhibitors to contribute. The international character of the " Linked Ring " encouraged an interchange of works between British and foreign exhibitors, with the result that the productions of certain French, Austrian and American photographers are perfectly familiar in Great Britain. This, in the year 1900, led to a very remarkable cult calling itself " The New American School," which had a powerful influence on contemporaries in Great Britain.
It may be well to glance at such improvements of process or apparatus as have not been direct and essential means to pictorial advance, but rather modifications and improvements made in response to the requirements of the artistic aspirant. Such improvements are of two orders those which are devised with the aim of securing greater accuracy of delineation, the correction of distortion and of apparent exaggeration of perspective, and the more truthful rendering of relative values and tones; and those which seek to give the operator greater personal control over the finished result. While great advances have been made in photographic optics, it cannot be said that pictorial work has been thereby materially assisted, some of the most successful exponents preferring to use the simplest form of uncorrected objective, or even to dispense with the lens altogether, choosing rather to employ a minute aperture, technically called a " pinhole." This is but one example of many which might be quoted to bear out the statement that in photography the advance of anything in the nature of artistic qualities has not been correlative with mechanical improvements. The hand camera can only be said to have had an indirect influence: it has increased the photographer's facilities, and by removing the encumbrance of heavy tools has widened his Sphere of operations; but it is perhaps in connexion with the plates and printing processes that more direct advantages have been gained. The fact that the actinic power of colours is not proportional to their luminosity was long regretted as an obstacle to correct representation; but by the introduction of orthochromatic or isochromatic plates in 1886 (when B. J. Edwards bought the Tailfer and Clayton patent, under which he shortly brought out his orthochromatic plates) this original disability was removed; while with increased rapidity in the isochromatic plate colour values may still further be corrected by the use of coloured screens or light filters, without interfering with the practicability of making sufficiently rapid exposures for most subjects. Again, by a better knowledge of what is required in artistic representation, certain modifications in the formulated treatment of ordinary and uncorrected plates are found to do much towards removing the evil; hence, with an ordinary plate " backed " so as to counteract overexposure of the higher lights, an exposure may, except in extreme cases, be given of length sufficient to secure the feeble rays of the less actinic colours, and by subsequent suitable development a result hardly distinguishable from that of a colour corrected plate may be secured. Chemical experiment has placed in the photographer's hands improved and easier means of entire, unequal and local intensification and reduction, but utility of these is restricted. By the artistic worker it is claimed that the lens and camera are but the tools, and the negative the preliminary sketch or study, the final print standing to him in the same relation as the finished painting does to the artist. In the production of the print various means of personally controlling the formation of the image have been resorted to. Thus the local development of platinotype by means of glycerine has its champions, but it seems to have been little used, its resuscitation being chiefly due to two or three prominent workers in New York. Here should also be mentioned the revival in 1898 of rough-surface printing papers, chiefly those sensitized with silver, the roughest texture drawing papers being employed to break up the excessive sharpness of the photographic image, and by the superficial inequalities introducing the effect of luminousness to over-dark shadows and variety to blank whites. The almost forgotten process of Pouncy, and of Poitevin, now known as the gum bichromate process, was rehabilitated in 1894 by M. Rouille Ladeveze expressly to meet the needs of the pictorial worker. Perhaps the best results that have been achieved by it are those of M. Robert Demachy of Paris, though many English workers have used it with remarkable success. In it paper of any kind may be selected as the support. The power of the operator to modify the printed image to almost any extent, even to introducing and eliminating lights and shadows, and in other ways to depart widely from the image given by the negative, depends upon the fact that the coating of gum and pigment (which, being bichromatized, becomes insoluble in proportion as it is acted upon by light) holds the pigment but imperfectly, and yields it up upon a vigorous application of water. According, therefore, to its application or retention, the operator can lighten or deepen in tone any portion. Numberless variations of other methods, such as brush development and local toning or stopping, have been suggested with the same object. Other workers have shown that by dexterously shutting off and admitting the light to various parts of the negative whilst printing, the disposition of the lights and shades in the print can be modified to so great an extent as to alter the general contour of the scene. Examples of an original unaltered print, and one which has been thus modified, are shown in the accompanying plate. Portions are shaded in by allowing the light to have access to the print, either through the negative in which case the image with all its details, prints more deeply or by removing the negative, when the action of the light is to flatten and suppress both detail and contrast. Latterly some few have resorted to extensive working on the negative, both on the back and on the film ; drawing by hand is practised on the film to render too prominent features less obtrusive, and objects in the background are merged by an intricacy of lines and cross-hatching. Many of the results are very pleasing, although one hesitates to justify the means, however good the end. On the other hand, to exclaim for purity of method and the exclusion of extraneous aids is very like setting up an arbitrary standard no less unreasonable than those conventions against which pictorial photography has so long striven.
AUTHORITIES. P. H. Emerson, Naturalistic Photography; H. P. Robinson, Picture-making by Photography; Art Photography; Pictorial Effect in Photography ; Elements of a Pictorial Photograph ; A. H. Wall, Artistic Landscape Photography (1896); A. Horsley Hinton, Practical Pictorial Photography (1898), and subsequent editions; C. Puyo, Notes sur la photographie artislique (Paris).
(A. H. H.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)