“The Kodachrome process invented by J.G. Capstaff in 1913 was a two-color subtractive process designed for still photography. The principle which made this process possible was discovered accidentally by Capstaff in 1910. He found that when a negative is treated with a tanning bleach, the negative image is removed and the area where it existed is differentially tanned. Subsequent treatment of the film with dyes capable of dying soft gelatin produced a positive dye image.
Examples of the results obtainable with the process were first shown publicly in November 1914 at the Memorial Art Gallery, Rochester, New York. Exhibits were also sent to London and to the Panama Pacific Exposition in San Francisco.
Because of its success as a process for still photography, experiments began the following year to adapt its principles to motion picture photography. A camera was constructed which used two lenses mounted one above the other to expose two frames at the same time, one through a red filter and one through a green filter. The film was advanced two frames at a time. The release prints consisted of a film support having dyed gelatin images on each side composed of the images from each pair of frames printed in accurate register.
The first story filmed in this process was an experimental film approximately 600 feet long called Concerning One Thousand Dollars, produced in July 1916. According to G. E. Mathews [=Matthews]8 it is believed that this picture was the first motion picture story to be photographed by a two-color subtractive process.
In 1929 this process was adopted by the Fox Film Corporation for introduction as Fox Nature Color. A laboratory for producing prints by this method was constructed in Hollywood at a stated cost of one million dollars. The addendum on pages 244-254 is a reproduction of the Instructions For Cameramen issued by Fox Film Corporation in 1929.
Transformation of the Kodachrome process from a process for still photography using glass plates into a workable process for motion picture photography presented several serious problems. Solution of the problem of obtaining a red light and a green light image by the simultaneous exposure of two frames through two lenses introduced the problem of parallax. When the object being photographed was at a distance the error due to the separation of the lenses was quite small, but when the object was at close range it became very objectionable. One method of overcoming this difficulty was to place a beam-splitter in front of the two lenses. The beam-splitter (Fig. 32) consisted of a system of prisms constructed in such a way that the normal light falling into one lens was blocked out and that falling into the other was divided into two beams, one entering each lens. The use of the beam-splitter, however, introduces a second error, particularly in the photographing of objects at very close range, namely a difference in the magnification of the two images. This is due to the fact that the optical path from the object to the lens which receives the light reflected by the prism is greater than the path from the object to the lens which receives the light transmitted by the prism.
In addition to the optical errors which it introduced, the double frame method of exposure employed in the Kodachrome process introduced certain physical limitations. The maximum diameter for any circular lens used in the process was the height of a single frame. Thus a two inch lens was limited to a speed of f/2.8 and a three inch lens to a speed of f/3.7. The effective speed was even further reduced by the use of a beam splitter and the filter factors of the red and green filters.
Because of the need for increased light and the general limitation of the amount of light that can be used on a subject in close up, it was frequently desirable to omit the beam splitter and thus increase the exposure obtainable with any given amount of light. When this was done the parallax could be corrected during one of the printing steps. However, the background would be out of register by an amount which would be greater for the more distant planes. This effect was more pronounced if distinct horizontal lines were noticeable in the background.
Processing of the original alternate frame red/green negative was accomplished in normal black and white developing equipment using normal black and white developer.
After the exposure and processing of the original negative the next step in the process was the preparation of the master positives. The camera negative contained a number of defects which must be corrected either during this stage or in the making of the final prints. These defects were:
1. Stereoscopic parallax and other horizontal errors in registry.
2. Lack of vertical registration.
3. Difference in magnification.
4. Differences in frame line position.
5. Differences in exposure on the two frames.
6. Differences in contrast.
In order to correct as many of these defects as possible, a special optical printer (Fig. 33) was employed for the printing of the master positive. This printer consisted of a projector with a film gate and pull-down mechanism for advancing and illuminating two frames simultaneously with diffuse light. The two frames were imaged at a magnification of approximately one-to-one by two lenses upon a single frame aperture in the camera head. The raw stock was pulled down one frame at a time; once while the two frames of negative are being pulled down and once in the middle of the rest period of the negative. Shutters located in front of each lens were timed so that the frames were alternately exposed onto alternate frames of master positive raw stock. The lens system was adjustable as a unit for changes in overall magnification, or each lens could be adjusted separately along its parallel axis or at right angles to the axis to correct for differences in individual image size, parallax and lack of vertical registry. To permit individual exposure control of each record, both lenses were equipped with adjustable diaphragms. Changes in overall contrast could be made by inserting filters in the beams.
In the early stages of the development of this process the master positives were contact printed without correction. Therefore, any corrections that were necessary had to be made in printing the final prints. This proved to be both difficult and uneconomical. It soon became evident that it was more practical and economical to introduce the corrections while preparing the master positive where speed and cost per foot were not important. Using this procedure, the release prints could be printed on a much simpler printer. The optical system for such a printer is shown in Figure 34.
The master positive was illuminated by a specular light system. By means of a beam splitter the alternate frames were printed on opposite sides of the double-coated print film.9 The film advance mechanism pulled down one frame of double coated film for each two frames of master positive. Shutters were included in the beams so that each frame of master positive was only printed on one side of the print film.10 After printing, the double coated film was developed to a negative in a conventional black and white developer, washed for ten minutes, then bleached in a bath which hardened the gelatin only in the areas where the image had been printed. Fixing after development was unnecessary since the bleach converted the silver to silver bromide which had to be removed by fixing after bleaching.
Potassium ferricyanide 37.5 grams
Potassium bromide 56.25 grams
Potassium dichromatc 37.50 grams
Acetic acid 10.0 ml
Water to 1.0 liter
Potassium alum 5% solution
When bleaching was completed the film was fixed in an acid, alum-free hypo solution and washed for twenty minutes. This wash was followed by immersion in a solution of 5% ammonia for three minutes, then an additional five minutes wash before it was dried. Figure 35 illustrates in diagram form the machine used to apply the dye to the finished print.11 As the film passed through the machine a series of roller applicators applied the dye to one side of the duplitized positive. Then the film was washed and dried and run through a second machine which applied the dye to the other side.
The amount of dye was controlled by counter tension rollers. The applicator rollers were not driven; only the mordanting rollers were driven.
Special dyes known as Kodachrome red and Kodachrome green were used in the dye applicating machine.12 Although their names and formulas are not available, they were probably of the pinatype family since they were only absorbed by the non-tanned portions of the print in the dyeing operation.”
8 MATHEWS [=Matthews], G. E., “A Motion Picture Made in 1916,” Journal of the Society of Motion Picture Engineers, November 1930, pp. 624-626.
9 CAPSTAFF, J.G., USP 1273457 applied for 1918.
10 CAPSTAFF, J. G., USP 1478599 applied for 1923.
11 CAPSTAFF, J. G., USP 1351834 applied for 1920.
12 FRIEDMAN, J. S., History of Color Photography (Boston: The American Photographic Publishing Company, 1944), pp. 467-468.
(Ryan, Roderick T. (1977): A History of Motion Picture Color Technology. London: Focal Press: pp. 66 ff.)
The other, a method of making color prints on duplitized film, expands on patent 1174144.”
(Ryan, Roderick T. (1977): A History of Motion Picture Color Technology.
London: Focal Press: pp. 65-66.)
“COLOUR PHOTOGRAPHY. No. 13,429, 1915 (Sept. 21, 1914). The following are the claims made in the specification the full text of which is printed on another page of this issue, in the “Colour Photography” supplement :
1. A process for making transparent photographs in colours of the kind in which two or more negative images, after being converted into dye-positives, are placed in superimposed registering relationship, characterised by the negative images before dyeing being bleached and differentially tanned in such a manner that a substantially transparent and a substantially colourless body is obtained for treatment in the dye bath, thus facilitating the dyeing of the image to the requisite depth or intensity.
2. A process for making transparent photographs in colours as claimed in Claim 1, in which the bleaching and differential tanning is produced by treating the negative image in a bath of potassium ferricyanide, potassium bromide, potassium bichromate, acetic or similar acid, and potassium alum, preferably in the proportions specified.
3. A process as claimed in Claim 1 in which the films are dried after treatment in the bleaching and differential tanning bath and then, after dyeing, are treated with dilute acid to fix the dye.
4. The process for making transparent photographs in colours as herein described.
5. Transparent photographs in colours made according to the process herein described.
GEORGE JOHN CAPSTAFF [sic!] , 16, Electric Avenue, Rochester, U.S.A.”
(1916): The Kodachrome Process. In: The British Journal of Photography, Colour Supplement, 10, 30-31, pp. 434.
TWO-COLOUR CINEMATOGRAPHY.—No. 13.430. 1915 (September 21, 1914). The full text of the specification describing the invention is published on another page of this issue in the “Colour Photography” Supplement, with the exception of the formal claims, which are as follows :
1. A method of preparing photographic reproductions in colours by projecting into register the images of the two separate non-superposed colour-sensation records on to opposite sides of a film or support sensitised upon each side and colouring differently the respective records thus produced, the last-mentioned film alone being coloured, though not colour-sensitive.
2. A method of preparing photographic reproductions in colours consisting in taking side by side duplicate or substantially duplicate negatives through separate colour screens upon a single-coated colour-sensitive film or support, producing a positive master record from the negatives, projecting simultaneously the duplicate images from the master record on to the opposite sides of a film or support sensitised upon each side and colouring differently the respective records thus obtained, the final product film alone being coloured, and the only emulsion which is necessarily colour-sensitive being that upon which the negatives are originally taken.
3. A method of preparing photographic reproductions in colours by projecting the images from two separate colour-sensation records substantially identical in outline, so that they are in register but upon opposite sides of a. transparent support carrying a sensitised medium upon each of its sides, developing the images thereby produced on the transparent support and converting them into dye positives.
4. The method of preparing motion picture strips or other photographic reproductions in colours.
5. A motion picture strip or other photographic reproductions in colours produced by the method described.
John George Capstaff, 16, Electric Avenue, Rochester, New York. U.S.A.
(1916) The Kodachrome Process. In: The British Journal of Photography, Colour Supplement, 10, 30-31, p. 435.)
“Furthermore, Twentieth Century-Fox experimented with the Kodachrome process between 1928 and 1930. Christened Fox Color, their system used a camera almost identical to the one developed by Capstaff 12 years earlier.
Thus, the exposure was accomplished through two lenses for most scenes. To overcome the disturbing parallax problems associated with this system during close-ups, the Fox laboratory developed a single-lens camera fitted with a beam-splitting prism.12 Despite their reported efforts, no feature utilizing the Fox Color/Kodachrome process was ever released.”
(Nowotny, Robert A. (1983): The Way of all Flesh Tones. A History of Color Motion Picture Processes, 1895-1929. New York: Garland Pub., p. 152.)
“The very first but short feature film in color was produced in 1916 by Kodak founder George Eastman using his Kodachrome process (not to be mixed up with the well known modem color slide and Super-8 materials of the same name). The title of this feature was Concerning 1000 Dollars. It was mainly filmed in Eastman’s private garden in Rochester, New York. The Kodachrome two-color cine film was photographed through a twin-lens in the special camera and printed on a double-coated positive film, which was dyed red-orange and blue-green respectively.
Though two-color film was not able to reproduce the full range of colors – and especially the blue of the sky and the green of the grass – it was fairly good for skin tones. Kodachrome had no success in Hollywood, although George Eastman and the inventor of this process, John Capstaff, tried hardly to introduce their process.
So Kodachrome was mainly used for fashion films and shorts of different kind, including the dance film Flute of Krishna produced in 1923. These films were also shown in the European countries. The 20th Century Fox became interested in Kodachrome in 1930, renaming it as “Fox Nature Color” – but reporting on it a newspaper commented: “Poor nature! Poor color!” Later, other kinds of two-color sound films proved to be more successful, among them the American Cinecolor and Magnacolor and the German Ufacolor. The last Hollywood plant for printing such films was closed in 1954.”
Koshofer, Gert (1996): Early Colorfilm Processes for the Cinema. In: Monica Dall’Asta, Guglielmo Pescatore und Leonardo Quaresima (Hg.): Il colore nel cinema muto. Bologna: Clueb, p. 43.
“The working principle underlying the two-color process known as Kodachrome is the use of a tanning bleach for treatment of the duplicate negative, which removes the negative image and differentially tans the area where the image existed. When the film is treated subsequently with dyes capable of dyeing soft gelatin, a positive dye image is produced.1
This tanning bleach effect was first observed accidentally by J. G. Capstaff about 1910 when engaged in experiments to find a method of making carbon prints without recourse either to artificial light or to daylight in order to tan the bichromated gelatin tissues. In the course of his work, a darkroom safelight was required and he decided to make one by dyeing a waste plate. Not having one handy, he used an old negative plate, which he bleached, washed, and immersed in the dye solution. On examining the plate he was greatly surprised to observe that it showed a dye image. No further use was made of the observation, however, until several years later, after he had joined the staff of the Kodak Research Laboratory.
Experiments on the Kodachrome process were initiated by Mr. Capstaff in the fall of 1913, using glass plates as the preliminary materials with which to work out the details although from the beginning the process was regarded as one to be developed for color cinematography.
So successful were these experiments that, in the fall of 1914, exhibits of color portraiture on plates were sent to London and to the Panama Pacific Exposition in San Francisco. Examples of the process were first shown publicly during the month of November, 1914, at the Memorial Art Gallery, Rochester, N. Y.2 Besides its use for portraiture, Kodachrome attracted the attention of the medical profession as a process especially adapted to photography of pathological specimens. Dr. N. T. Beers, a prominent Brooklyn surgeon, has made many fine color transparencies with the process during the past fifteen years.
Early in 1915, the first experiments were started to work out the adaptation of the process to motion picture photography. A three-color camera was made over into a two-color camera using twin lenses for exposing the film, two pictures at a time, through green and red filters, the pull-down moving two frames each time.
The method of printing3 consisted in printing negative images from a master positive on opposite sides of a double coated film by means of an optical printer, a rough sketch of which appears in the figure. The duplicate negative was then bleached in a tanning bleach, cleared, and dyed with dyes complementary to the dyes used in the camera filters. The developing and dyeing equipment was of the crudest sort for these first experiments, and considering this fact, the quality of the pictures obtained at that time was remarkably good.
After the preliminary tests had been made on the process during 1915, it was decided to test the practical value of the method by actually photographing a motion picture story. Incidentally it was considered that this would reveal the weaknesses of the process as well. Miss Sylvia Newton prepared a scenario and the scenes were “shot” on the roof of the Laboratory and in Mr. Eastman’s garden. Outside of the film and laboratory labor, the cost of the production was about zero. It is believed that this picture is the first motion picture story to be photographed by a two-color subtractive process. Gaumont and Urban had, of course, made pictures by additive processes previous to that time. The date of the production, July, 1916, is established by a date on an actual letter written by request which appears in the first part of the picture.
The cast of characters in the picture which was called Concerning $1000 was as follows:
A promising young inventor H. L. Halburt
His sister Sylvia Newton
A friend Doris Long
A child Doris Mees
The father Dr. C. W. Frederick
The results were naturally crude considered in the light of quality of present day color pictures, but are historically interesting as an example of an early color process. It may be noted in passing that one member of the cast has since married and is the mother of two grown children, whereas another member, the child, is now ready to enter the university.
Note. The original two-color subtractive print (about 600 feet long) was shown at the conclusion of the paper.
1 U. S. Pat. 1,196,080, applied for Sept. 21, 1914.
2 Brit. J. Phot. Color Supp., 9 (Jan. 1, 1915), p. 3. See also note in Brit. J. Color Supp., 8 (December 4, 1914), p. 48.
3 U. S. Pat. 1,478, 599, applied for Sept. 21, 1914.”
(Matthews, Glenn E. (1930): A motion picture made in 1916 by a two-color subtractive process. In: Journal of the Society of Motion Picture Engineers, 15,5, 1930, pp. 624-626.)
“The original “Kodachrome” process was the invention of J. G. Capstaff, of Kodak Research Laboratories (E.P. 13,429, 1915). The negatives were taken by a beamsplitter camera. Positive prints were made, and from these negative images were printed in register on double-coated film. The images were bleached, the bath hardening the films only in the parts where the image had been. The two sides were then dyed in the usual two colours, namely red-orange and blue-green, the dyes entering the emulsion only in the unhardened areas, thus giving positive images. The silver was finally entirely removed.”
(Klein, Adrian Bernhard = Cornwell-Clyne (1940): Colour Cinematography. Boston: American Photographic Pub. Co.. 2nd revised edition: pp. 14.)
Die Aufzeichnung der verschiedenen Grauwerte eines Schwarzweißfilmbilds kann jeweils in einer einzigen lichtempfindlichen Schicht erfolgen. Die Farbfilmaufnahme und -wiedergabe erfordert jedoch – soweit keine Farbrasterung erfolgt – für jeden Farbauszug eine besondere, nur für einen bestimmten Farbenbereich lichtempfindlich gemachte Schicht.
Bei der in Zweifarbenverfahren üblichen Blau-Rot-Zerlegung des Bildes besteht die Möglichkeit, zwei Filmstreifen mit Emulsionen entsprechender Empfindlichkeit Schicht an Schicht liegend durch das Bildfenster der Aufnahmekamera zu führen und gleichzeitig zu belichten. Der zum Objektiv gelegene Frontfilm ergibt dann in seiner orthochromatischen Schicht den Blauauszug, der hinter ihm liegende Rückfilm unter Rotfilter in seiner Panchroschicht den Rotauszug. Die Rohfilmindustrie liefert dieses zweifache Negativmaterial als Bipack. Die Mehrzahl aller subtr. Zweifarbensysteme arbeitet mit Bipacknegativ; durch gleichzeitige Verwendung eines dritten, grünempfindlichen Negativs werden auch Dreifarbenaufnahmen möglich.
Mehrschichtenfilm als Kopiermaterial ist als doppelseitig beschichteter Positivfilm (Dipo-Film) schon lange im Gebrauch, auch doppelseitig beschichteter Tripo-Film (eine Schicht auf einer, zwei auf der anderen Seite des Schichtträgers) wird als Kopiermaterial verwendet. In neuerer Zeit wird Mehrschichtenfilm als Monopack-Aufnahmematerial (Umkehrfilm) hergestellt, bei dem drei verschieden sensibilisierte Halogensilberschichten und trennende bzw. filternde Zwischenschichten übereinander gegossen auf einer Seite des Schichtträgers liegen.
Diese vollkommenste Form von Mehrschichtenfilm (Agfacolor chem. und Kodachrom) ist in jeder Kamera als ideales Aufnahmematerial zu verwenden, ebenso als Farbschichtfilm in jedem Projektor wie Schwarzweißfilm vorzuführen. Die besonderen Schwierigkeiten rationeller Vervielfältigung sind z. Zt. noch nicht völlig überwunden.”
(Dr. N. (1937): Mehrschichten-Film. In: Film-Kurier, 27.8.1937, Serie “Farb-Film-Fibel”.) (in German)
“A typical two-color subtractive process is that worked out by J. G. Capstaff in the Research Laboratories of the Eastman Kodak Company. The silver is treated in such a way that the reaction products harden the gelatin selectively and thus a silver negative is transformed directly into a dye positive. In order to apply this to motion picture work, the negatives are taken in a camera in such a way that red and green pictures are taken successively, one below the other (Figure 21).
From this strip of negative film a master positive is made, and this is then printed by means of a special projection printer upon opposite sides of double-coated film (Figure 22).
In this projection printer, the red positive is projected on to one side of the film and simultaneously the green picture on to the other, the images being slightly displaced vertically, so that they exactly register one on top of the other on opposite sides of the film. The emulsions being exactly the same and the light intensities the same, there is no difficulty in obtaining equal results in the two pictures. The strip is then developed and fixed for the two pictures and without further delay is passed into the bleach bath, which bleaches the silver and locally hardens the gelatin where the silver was present. The silver is then fixed out, leaving a clear-coated gelatin strip of film bearing, on both sides, the images in the form of hardened gelatin. The two sides are then dyed by passing through a dyeing machine, the side containing the pictures taken through the red filter being dyed blue-green, and the side containing the pictures taken through the green filter, red. On viewing the film so prepared, a two-color subtractive picture is seen, which, being on standard film, can be run in any machine in the same way as black and white.”
(Mees, C.E. Kenneth (1929): The Processes of Color Photography. III. Color Cinematography. In: The Journal of Chemical Education, 6, pp. 44–51, on p. 48.)
“An additive color process was the most achievable first step, but it had already proved to be an inadequate technique. By the late 1910s other processes were already applying subtractive color for motion picture use, and the introduction of new photographic products from Eastman Kodak seemed to make it a viable solution for the KC&W engineers. Having the color as an integral part of the film print eliminated the need for special projection equipment or handling, and immediately opened up the possibilities for wider distribution and adoption by the industry. Prizma Color and Eastman Kodak’s Kodachrome1 color processes were proving the advantages of subtractive color, but both were still flawed.
1 Two-color Kodachrome should not be confused with the later Kodachrome process introduced by Eastman Kodak in 1935. The latter was a three-color multilayer reversal film largely used for slides and amateur motion pictures on 8mm and 16mm until it was discontinued in 2009.”
(Layton, James; Pierce, David (2015): The Dawn of Technicolor. Rochester: George Eastman House, on p. 59.)
“Subtractive color employed principles opposite from those of additive. Instead of combining colored light to create an image, subtractive processes worked by absorbing wavelengths of light, removing parts of the spectrum to leave the remaining colors visible. These techniques were preferable in obtaining good color rendition for motion pictures, but they were difficult to achieve. Additive processes may have been successfully demonstrated and commercialized first – most prominently by Kinemacolor – but the results on screen tended to be flawed and often difficult to watch. In recombining the color records in projection, fringing, flickering, and poorly illuminated images were frequent side effects.
Three-color subtractive photography as a principle was simple. Once three color records – red, green, and blue – had been recorded onto black & white negative, the resulting prints or transparencies were dyed the corresponding colors – cyan, magenta, and yellow. Bringing the three color positives together superimposed in register created a full-color image.
These principles were thoroughly understood and often exploited in an experimental manner in the photographic world, but practical solutions for capturing and delivering three-color images were complicated and nearly impossible for motion picture use. Like their predecessors, KC&W’s engineers opted to capture two colors instead of three for their additive process. Comstock’s sensible “step development” strategy first required the perfection of an entirely new printing process and the refinement of the principles behind Technicolor’s first color camera.
Several notable firms had already begun exploring subtractive color, with varying results. Prizma had quickly evolved from its first additive processes to a subtractive printing technique by 1918, but remained tied to its outdated camera technology. Eastman Kodak’s Kodachrome process and Brewster Color, developed in tandem from 1913, shared similar printing technology, but had different cameras. All three processes relied on double-coated, or duplitized film, to render color images.”
(Layton, James; Pierce, David (2015): The Dawn of Technicolor. Rochester: George Eastman House, on pp. 61–62.)
“Eastman Kodak began work on its Kodachrome process after Percy Douglas Brewster first contacted the Kodak Research Laboratories in 1913. The inventor requested the experimental development of several new photographic products to further his own process.8 John G. Capstaff of Kodak recognized the flaws in Brewster’s plans, and was able to devise more advanced results through further refinement. The Kodachrome process was beautiful to behold – with realistic color rendition for a two-color process, vivid saturation, and lifelike flesh tones – but its camera technology was less sophisticated. Capstaff took an unused additive three-color Chronochrome camera sent to Rochester a few years earlier by Leon Gaumont and modified it for two-color photography. Two lenses, one above the other, recorded color separations onto the negative simultaneously. The use of twin lenses meant less light was required than with most rival processes, but they introduced spatial parallax, caused by the slight variation in angle of each lens. A fair amount of this misalignment could be corrected through optical printing, but fringing was impossible to remove entirely.
8 C.E. Kenneth Mees, letter to George Eastman, November 2, 1914, Kodak Historical Collection #003, Rare Books and Special Collections, Rush Rhees Library, University of Rochester.”
(Layton, James; Pierce, David (2015): The Dawn of Technicolor. Rochester: George Eastman House, on p. 63.)
“All-color shorts were commonplace in the 1920s, but few had been made in Technicolor. Notable exceptions included the Hope Hampton short Marionettes (1925) and a series of three “Romance Productions” in 1926. Audiences had become used to seeing both natural- and applied-color short subjects on theatre bills. Prizma had built its business model producing color travelogues and documentaries in the early 1920s, and others had followed. New stencil-colored actuality footage was offered weekly in the “Pathé Review” series; animation, documentary, and novelty shorts were colored by William Van Doren Kelley’s Kelley Color process; and Eastman Kodak Company’s two-color Kodachrome was used prominently for the “McCall’s Colour Fashion News” series, also star ring Hope Hampton. Other smaller-scale efforts sprang up, mostly producing advertising and industrial shorts.”
(Layton, James; Pierce, David (2015): The Dawn of Technicolor. Rochester: George Eastman House, on p. 180.)
“In der praktischen Auswertung blieb Kodachrome jedoch hinter Konkurrenzverfahren ähnlicher Funktionsweise zurück, wie dem zwischen 1920 und 1923 florierenden Prizmacolor Prozess Nr. 2 (William van Doren Kelley), bei dem es sich um ein additiv-subtraktives Kombinationsverfahren handelte: Die Aufnahme der Farbauszüge erfolgte nach dem seit Kinemacolor bewährten Folgeverfahren; die Anfertigung subtraktiver Kopien ermöglichte die unbeschränkte Auswertung der durch die Prizma Inc. produzierten Filme. Seine erfolgreiche Vorstellung erlebte das Verfahren 1919 mit dem aus Landschaftsaufnahmen montierten Streifen Everywhere is Prizma, dem eine größere Zahl Kulturfilme – Nippon, Ruins of Angkor, So this is London (alle 1921), Algeria the Ancient, Fashion Hints (beide 1922), Oases of the Sahara, From the Land of the Incas (beide 1923) – folgen sollten. Kelley gelang mit seinem Prizmacolor Prozess Nr. 2 auch, was Kodachrome versagt geblieben war, nämlich in Hollywood Fuß zu fassen: Bereits 1920 entschied D.W. Griffith, der auch mit Kodak in Verhandlungen gestanden hatte, eine Sequenz seines epischen Dramas Way Down East (1920) in Prizmacolor herzustellen.”
(Alt, Dirk (2011): “Der Farbfilm marschiert!” Frühe Farbfilmverfahren und NS-Propaganda 1933-1945. München: Belleville, on pp. 41–42.) (in German)
“Il boom dei talkie in bicromia nel biennio 1929-1930 fu caratterizzato da una continua euforia della visione. Assieme ad altri sistemi impiantati su più piccola scala negli stessi anni, il Technicolor concorse per qualche tempo a offrire sontuose portate al banchetto del film sonoro31.
31 La Fox ad esempio optò per il Kodachrome, sistema sottrattivo in bicromia della Eastman Kodak messo a punto nel 1916, che fu per l’occasione ribattezzato Fox Nature Color.”
(Pierotti, Federico (2012): La seduzione dello spettro. Storia e cultura del colore nel cinema. Genova: Le Mani-Microart, on p. 129.) (in Italian)
“Mit fortschreitender Entwicklung ist die Herstellung des Farbenbildes durch Heranziehung geeigneter photographischer, chemischer oder optischer Hilfsmittel ganz mechanisiert worden. Sie fußen auf der Zerlegung des farbigen Bildes in mehrere Teilfarbenbilder, die in geeigneter Weise kombiniert werden. Man unterscheidet nach der spektralen Auswahl zwei Gruppen farbenkinematographischer Methoden:
1. Die Zweifarbenverfahren,
2. die Dreifarbenverfahren.
Diese teilen sich wieder nach der Farbensynthese in zwei (von der ersten Unterscheidung unabhängige) Gruppen:
1. die subtraktiven Verfahren,
2. die additiven Verfahren.
Wir besprechen zuerst die subtraktiven Methoden und beginnen mit den Zweifarbenverfahren. Die beiden typischen Farbstoffe, die letzten Endes die Farbwirkung hervorrufen, sind ein Orangerot (1) und ein Blaugrün (2). Durch diese beiden Komponenten, ist das Spektrum, grob gesprochen, in zwei Teile zerlegt. Reine rote bis gelbe Töne werden stets durch Farbstoff (1) wiedergegeben; dabei kann natürlich die Anfärbung vom satten Grundfarbstoff bis zum Weiß (unangefärbt) stattfinden. Das gleiche gilt für Farbstoff (2), der die Töne von Grün bis Blau vertritt. Schwarz wird durch räumliche Hintereinanderlagerung beider Farbstoffe (zwischen Lichtquelle und Schirm) gewonnen, denn der blaugrüne Teil des Spektrums wird zunächst durch (1) ausgelöscht und der rotgelbe Teil durch (2) verschluckt.1 Das weiße Licht wird also in 2 Portionen fortgenommen – daher die Bezeichnung “subtraktive Methode”. Die Grauleiter entsteht entsprechend durch Hintereinanderschaltung schwächerer (aber in Summa neutral wirkender) Anfärbungen von (1) und (2), und schließlich besteht die Möglichkeit, durch Kombination verschieden kräftiger Anfärbungen beider Farbstoffe eine relativ umfangreiche Reihe von Mischfarben (z.B. die Fleischfarbe) hervorzubringen. Das Problem besteht nun darin, diese beiden Farbstoffe jeweils in der richtigen Konzentration an die richtigen Stellen der beiden Teilbilder zu bringen, die durch Über- oder Hintereinanderlegung die Gesamtwirkung hervorrufen.
Zur Herstellung der beiden Teilnegative bestehen hauptsächlich zwei Möglichkeiten: die Strahlenteilung und der Zweipack. Wie Abb. 1 an einer schematischen Darstellung des Strahlenteilungsprinzips unter Fortlassung der Linsenoptik zeigt, fällt das vom aufzunehmenden Objekt kommend Licht zunächst auf den halbdurchlässigen Spiegel S. Die eine Hälfte der Strahlung wird reflektiert und erzeugt auf dem (panchromatischen) Film p2 hinter dem Rotorange-Filter F2 ein Bild des Rotorange-Anteils, da das vorgestellte gleichgefärbte Filter die übrigen Lichtarten fortnimmt. Die andere Hälfte der Strahlung geht durch S hindurch und entwirft auf dem Film p1 den Blaugrün-Auszug, weil das eingeschaltete gleichfarbige Filter F1 den komplementären Teil des Spektrums absorbiert. Mit Hilfe der Perforation des Films lassen sich die zusammengehörigen Bilderpaare exakt zu konturgetreuer Deckung bringen, wenn durch die sonstigen optischen Bedingungen der Apparatur identische Abbildungen gesichert sind. Es besteht also auch die Möglichkeit, die auf den Einzelfilmen p1 und p2 erzeugten Bilder durch geeignete Hilfsmittel auf einem gemeinsamen Film untereianderstehend anzuordnen, wobei nach jeder Aufnahme die doppelte Filmlänge wie normal transportiert wird; solche Negative werden nicht im Kontakt, sondern optisch kopiert. – Abb. 2 zeigt die Trennung der Lichtarten nach dem Zweipackverfahren, bei dem die Aussonderung der beiden komplementären Lichtarten durch die verschiedene spektrale Empfindlichkeit der photographischen Schichten erfolgt. Ein blaugrünempfindlicher Frontfilm liegt bei der Aufnahme Schicht an Schicht und im engen Kontakt mit einem rotempfindlichen Schlußfilm. Das Licht tritt in den Zweipack durch das Zelluloid a des Frontfilms ein, gibt auf diesem den Blaugrün-Auszug, während das organgerote Licht auf die Schicht des Schlußfilms d wirkt, nachdem es durch ein mit dem Frontfilm verbundenes Orangefilter c von den Resten der Blaugrünstrahlung befreit wurde. Auch in dieser Anordnung wird durch die Perforation das exakte Aufeinanderpassen der beiden Bilder gewährleistet. Bemerkt sei noch, daß unter Einschaltung eines zweiten halbdurchlässigen Spiegels in die Strahlenteilungskamera oder eines Zwischenfilms beim Dreipack2 der Übergang zur Dreifarbenphotographie möglich ist, da auf diesem Wege (bei Anwendung entsprechender Filter) drei getrennte Farbauszüge herstellbar sind.
Mit Hilfe der auf die eine oder andere Weise gewonnenen beiden Teilnegative ist nun im anschließenden Positivprozeß die Einführung der genannten beiden Farbstoffe zu bewerkstelligen. Dies kann nach zwei Verfahren geschehen. Entweder man stellt von den Negativen auf photographischem Wege oder mit Hilfe des Chromatprozesses Gelatinereliefs her, die man im komplementären Sinne anfärbt und im Absaugeverfahren auf einen Blankfilm mit Gelatineüberzug hintereinander und unter Innehaltung exakter Konturdeckung überträgt; der Orangerot-Auszug liefert also das blaugrün gefärbte Teilbild und umgekehrt, wobei schließlich beide Bilder auf der gleichen Schichtseite des Blankfilms übereinanderliegen. – Oder man kopiert (wie Abb. 2 zeigt) die beiden zusammengehörigen Teilnegative gleichzeitig auf einen zwischen ihnen liegenden doppelseitig begossenen Positivfilm, so daß die entsprechenden Kopien zunächst als Silberbilder auf getrennten Seiten liegen. Verwandelt man diese in Farbstoffbilder durch chemische Tonung (Eisenblau- oder Urantonung) oder durch Virage (z. B. Jodsilberbeizfärbung) wiederum im komplementären Sinne, so ergibt sich ein ebenfalls wie beim Absaugeverfahren, subtraktives Zweifarbenbild. Schließlich kann man auch die Negative oder zweckmäßiger die auf einem doppelseitig beschichteten Film einander gegenüber angeordneten Duplikatnegative in gebleichte Gerbreliefs überführen und zu den Aufnahmefiltern komplementär anfärben. Die nachfolgende Tabelle zeigt, in welcher Weise eine Anzahl bekannter Verfahren die genannten Methoden (in zum Teil etwas modifizierter Weise) kombinieren. In der letzten Spalte der Tabelle wird auf die beiliegende Tafel verwiesen, für die die Firmen Technicolor Motion Picture Corp., Boston, Eastman Kodak Co., Rochester, Multicolor-Films-Inc., Los Angeles, Universum Film. A.-G., Berlin, und “Sirius” Farben-Film Ges.m.b.H., Berlin, einige Probebilder in dankenswerter Weise zur Verfügung gestellt haben.
Dem Multicolor-Verfahren ähnlich sind das Magnacolor-, Polychromide-, Photocolor-, Colorcraft-, Coloratura- und andere Verfahren, die zum Teil die Strahlenteilung als Aufnahmemethode verwenden. Das Harriscolor-Verfahren bedient sich eines einschichtigen Positivfilms und erzeugt die einzelnen Teilbilder in verschiedenen Schichttiefen. Das Foxcolor-Verfahren ist dem Kodachromverfahren analog. Bei dem Zoechrom-Verfahren werden die den einzelnen Teilnegativen entsprechenden Teilbilder auf nacheinander aufgebrachte Schichten nacheinander kopiert, entwickelt und gefärbt.
Bei den subtraktiven Verfahren wird grundsätzlich so vorgegangen, daß von dem ursprünglich weißen Licht durch geeignete Farbstoffe diejenigen spektralen Anteile entfernt werden, die nicht dem aufgenommenen Objekt entsprechen: die gewünschten Bildfarben bleiben als Differenz
1 Bei gewisser Farbstoffauswahl bleibt übrigens gelegentlich an Stelle von Schwarz ein Lichtrest in der Tönung von dunkler Sepia zurück.
2 Diese Anordnung wurde bisher nur für die Zwecke der Amateurphotographie, nicht für Kinefilm benutzt.”
(Eggert, John (1932): Kurzer Überblick über den Stand der Farbenkinematographie. In: Bericht über den VIII. Internationalen Kongress für wissenschaftliche und angewandte Photographie, Dresden 1931. Leipzig: J. A. Barth, pp. 214–221, on pp. 215–218.) (in German)