Gaspar Color subtractive 2 color
1941 – 1944
Subtractive 2 color: Silver dye-bleach
Wyckoff, A. (1941): Gasparcolor Comes to Hollywood. In: American Cinematographer, 22,11, Nov., pp. 510–511.
Comes To Hollywood
By ALVIN WYCKOFF, A. S. C, D. Sc.
FOR a number of years we in Hollywood have heard, in trade-paper news items and occasional all-too-brief abstracts from foreign technical papers, of a three-color process known as “Gasparcolor,” which was being used in pre-war Europe’s film centers. Shortly before the start of the conflict, the first examples of George Pal’s “Puppetoons,” screened under the auspices of the Academy of Motion Picture Arts and Sciences, gave us our first glimpse of Gasparcolor on the screen. The results even then indicated that if the process were brought to America, there might well be a new and worthy contender in the three-color field.
Today we learn that Gasparcolor has come to Hollywood where it is being launched with adequate financial and technical backing, with such well-known figures as George Converse as President, Captain James Roosevelt as Vice-President, and A. J. Guerin, A.S.C., as manager.
Essentially a printing process, Gasparcolor is today available in both twocolor and three-color versions, for direct 35mm., 16mm., and 16mm.-to-35mm. color enlargements. Based on the use of a special, dye-coupler reversal-type positive film, Gasparcolor prints can be made in any standard black-and-white film laboratory with only minor modifications of methods and equipment, and with a remarkably full range of control. No form of imbibition or color-flotation is used.
The Gasparcolor process is a product of the scientific mind of one of Europe’s foremost color researchers, Dr. Bela Gaspar. Conceived and perfected in Gaspar’s European laboratory, the process has now been adapted to American standards of equipment, methods and quantity production. Gasparcolor raw stock is manufactured in the United States exclusively, and is available in any desired quantity and guage. The manufacturing process incorporates the color dyes in predetermined quantity and quality, and in both three- and two-color stock.
The two-color stock has two emulsions, one on each side of the celluloid base. These consist of a normal reversal-type silver emulsion with the addition of blue dyes on one side, and a mixture of red and yellow dyes in the emulsion of the other side.
The three-color stock, as it is manufactured now, has two layers of dye – magenta and yellow – added to the silver emulsion on one side; the silver emulsion of the other side carries a layer of blue-green dye.
There is no intricate mystery in the manufacture of the raw stock; any manufacturer of motion picture film can produce it, thereby opening his participation in the color field by supplying a special stock to the industry.
After separation negatives have been made either direct in the camera or from a master Kodachrome original, intermediate positive are made by printing the separation negatives on black-and-white fine-grain stock. These intermediate positives are then used to print on color stock.
If it is desired to reproduce in two colors, the intermediate positive made from the blue separation is printed upon the red layer, and the intermediate positive from the red separation is printed upon the blue layer. If the three color process is desired, the intermediates from the red, green and blue separations are printed on the blue-green, magenta and yellow layers respectively. The printed color stock is then developed.
The printing lights are determined as they are in black-and-white practice and regulated in the same manner, as the final dye-image is controlled by the density and gamma of the silver image.
After development and washing, the film is fixed, conducted through a dye-coupler bath, washed, and in the subsequent solution the residual silver solution is destroyed. The film is again fixed, washed and dried.
The resulting color film is a base covered with gelatin containing the pure dye-image without any silver whatsoever, except in the sound-track.
The sound-track is redeveloped before the final fixing by the aid of a simple device, consisting of a small wheel with a concave profile, that applies a redeveloping solution of a fairly thick consistency over the area of the sound-track.
The quality of the final dye-image is controlled through the various stages of the process by the initial silver image, the quality of which is in turn controlled by the technique employed to control any black-and-white image.
The final dye-image is a composite image consisting of two or three dye-part images. To secure the final print, these images must be printed in perfect register on precision step-printers equipped with registration-pins. Another requirement of the printer is that it should be equipped with a constant light source that can be regulated by a variable shutter, or changing aperture, or other reliable mechanical method that will be effective in the required changing of light-intensity.
There is also available an optical skipping-printer for the purpose of separating every other negative image in the case of the alternate-frame, single-negative two-color used in cartoons etc., printing alternate frames or every third image in the case of three-color cartoon negatives, printing every third frame, in order to get the color separations as consecutive images on two or three separate films, respectively, to be printed onto a single color-film position in register.
In all other respects, a laboratory using the Gasparcolor process would use the same equipment and meet the identical requirements of any efficiently conducted black-and-white processing laboratory.
The optical quality of the finished print is smooth and transparent, devoid of any objectionable grain, as the size of the dye particles that combine to form the image is only a fraction the size of the silver grain. Although the dye-image reproduces faithfully the silver image, thereby also reproducing the individual silver grains by forming the composite image in several overlaying part images, the definition of the composite image is at least equal to that of black-and-white, and in many instances renders finer tones than of the black-and-white film serving as the intermediate positives.
The viscosity of the emulsion of the Gasparcolor stock is constant and identical. The coating is accomplished and regulated with the same technique and machinery as with normal black-and-white. Thus a fluctuating density can not occur unless a mechanical disarrangement takes place in the regularation of the printing process.
For obtaining the master negatives any 35mm. three-color camera that can produce a rock-steady image, or any 16mm. camera such as the professional Berndt-Maurer, Bell and Howall, or Eastman Special, using Kodachrome, will be adequate and render good results, according to the the operator behind the camera.
Excellent separations and blow-ups from 16mm. Kodachrome to 35mm. Gasparcolor are being obtained with definition comparable to original 35mm. separations of equal original quality and gradation.
In making enlargements from 16mm. the master Kodachrome is never projected or otherwise handled beyond absolute necessity. No attempt is made to lacquer the original or to correct any defect that might appear. All corrective work is done on subsequent negatives and positives, including the printing of edge numbers, thus reducing to an absolute minimum all defects that might appear in the 16mm. master.
A visit to the Hollywood Colorfilm laboratory in Burbank, which is now actively in production with 16mm. and 35mm. Gasparcolor, revealed the process technique of Gasparcolor and proved to be absorbingly interesting as well as instructive, and a revelation in discovery of a color process that was well known in Europe before the war, but comparatively new to the United States.
All the precision equipment at this laboratory is the finest precision motion picture machinery that mechanical skill can produce, and carries the well-known name of “Duplex.”
Tests, temperature, and control of developing solutions is by pH control. Bleaching baths are checked by colorimeter. Gamma-strips are run frequently and checked by an electronic densitometer. The control of printing-lights is by electronic voltage regulators using direct current. Light-tests are made on the visual sensitometer.
It was in the projection-room that the amazing beauty of Gasparcolor translations of the original subject were revealed.
From two synchronized 16mm. projectors, placed four feet apart, an original subject photographed on 16mm. Kodachrome stock was projected from one machine, while the same subject, duplicated on Gasparcolor stock, was Projected from the other.
The subject was a musical short. Colorful costumes, settings and beautiful girls. It was very well done. The photographic technique was smooth, evenly danced and beautifully lighted. Smooth cutting from long- and medium-shots to close-ups, properly timed wipes, fades and dissolves. For a short subject in color it was a delightfully entertaining success.
The Gasparcolor reproduction was true in every detail, the exception was in favor of Gasparcolor’s brilliance, projected with lamps of the same voltage; both projection machines were identical.
This demonstration was followed by one of the same subject reproduced with the Gasparcolor two-color process. This revealed a surprisingly fine skin texture and better definition of half-tones than has been seen in other two-color processes. The quality was brilliant, smooth and sharp. The two-color version of Gasparcolor represents really more than the cutting of the spectrum into equal halves. There is a definite, controllable, and reproducible dichroic effect, rendering good facial skin-color with red lips, and surprising separation of green and blue, affording definitely beautiful results that can be used to in-crease the value of the subject-matter suited to two-color photography, and of course at less expense than the three-color reproduction.
The black-and-white reproduction from the original color was superior to any attempt of black-and-white exposure through a system of filters attached to the camera lens. There was a roundness, and depth of focus, apparent only in good color rendition.
The next demonstration was a projection of the same subject enlarged to 35mm. in three-color Gasparcolor. The result was amazing. The color, sharpness, and sound had lost none of the excellent quality of the original. There was a difference, but again it seemed to be in favor of Gasparcolor. The color-balance, obtained through control in making the separations, was perfect. Shadow-detail was brighter and more luminous. Skin-texture was smooth and delightful, and the highlights were a soft and delicate balance for the lower key of lighting.
The reduction process from 35mm. to 16mm. of black-and-white from color, or black-and-white direct, and from 35mm. to 16mm. and from three-color to two-color, or three-color was entirely successful, producing a 16mm. product of excellent quality without impairing the fine range and tones of the 35mm. sound and picture. The production possibilities of any producing unit seem to be unlimited through this channel of Gasparcolor.
To the commercial advertiser, who needs a number of prints of a 16mm. business film, there is the unquestionable advantage of being able to display his product in its true tempting colors. The wrapping of merchandise, or the merchandise itself, may be shown as it would appear on the shelf.
Documentary films would be enhanced by the added documentation of color, and the lasting quality of the dyes used in the positive film will make for prints of permanent record.
For visual Education, many scenes in black-and-white become just so many pictures, but when the object of the lesson is presented in true color it is remembered. The training for various vocations, and especially today, military training in all its phases would be simplified, and the subject of the film would be better retained mentally if instructional films were presented in color.
In enlargements from 16mm. Kodachrome the result is not limited to a lighter, or darker, product than the original, because the application of the method of correction in Gasparcolor is so pliable that variations of shade are controllable. There is no indication of the unpleasant contrast which often results in the usual 16-to-35 enlargement.
Thus it may be concluded that in the Gasparcolor process, the industry has gained a needed, and potentially very valuable method of producing color films for virtually every purpose for which either 35mm. or 16mm. motion pictures are used. Most significant, too, is the fact that this process is the first commercially-available color system to offer the possibility of processing color in existing black-and-white laboratories. Sooner or later, so all authorities agree, the motion picture industry will swing to an almost 100% color basis: and when that happens, it seems scarcely possible that any single laboratory or group of specialized color-film laboratories could successfully handle the huge volume of footage necessary to handle the entire industry’s output. But if the industry’s present black-and-white laboratories, with only minor modifications, could, as in the Gasparcolor process, handle color, the universal acceptance of color would certainly come about much sooner. END.”
(Wyckoff, A. (1941): Gasparcolor Comes to Hollywood. In: American Cinematographer, 22,11, Nov., pp. 510–511.)