International photographer (Jan-Dec 1935)

Fourteen The INTERNATIONAL PHOTOGRAPHER May, 1935 Camera and Projection Technique of Crosene Color Process By Silvio del Sarto N the February issue of International Photographer we announced something new in color under the motion picture suns — the development to the point of commercial practicability of the Crosene Four-Component Additive Process for color cinematography. The following month we again devoted a certain amount of space to some very general remarks concerning the remarkable spectral fidelity, the simplicity, and the economy with which the Crosene system would permit the reproduction of color on the screen. Considerable interest has been aroused in the photographic industry, and particularly amongst cinematographers, since the first announcement of the Crosene Process to the picture making world. Naturally, a great many inquiries have been received concerning that which seems to be a revolutionary factor in the picture business. A good share of these have been concerned with the changes, if any, which the Crosene Process necessitates in conventional camera and projection technique. In the present instance we will confine ourselves to answering this question as briefly and non-technically as possible. It has been pointed out in a previous article that the Crosene positive print bears four identic and isomorphous images, each of a specific color value, within the film area normally occupied by a conventional black and white frame ; and that while each of these four images is of a different chromatic value than the other three, all four are derived from an original bi-pack separation. Therefore, whatever changes in camera technique are dictated by normal bi-pack work, the same changes, and only those changes, are necessary in color reproduction by the Crosene Process. The changes in the camera itself require the addition of a double magazine to carry the bi-pack negative, and an adjustment in the pressure plate at the film gate to permit the passage of the double negative. This adjustment is most important. The two negatives must be in optical contact throughout their entire frame areas in the aperture of the camera if perfect registration is to be secured in the finished print ; yet the pressure against the plate cannot be so great as to cause the film to drag or the perforations to tear. The bi-pack negative used in photographing by the Crosene Process is obtainable only from the Crosene Company. While it is standard stock, it has been especially treated in the Crosene laboratory in «rder to secure a more precise primary color separation, without, however, either adding to or subtracting from the photographic characteristics of its emulsion. The double negative is loaded in the camera exactly as in normal bi-pack work ; that is to say, emulsion to emulsion, with the orthochromatic negative next to the lens. As to the actual "shooting" of the negatives, it is as difficult to prescribe general rules for the color photographer as it is for the black and white one. Each cameraman has his own theory as to what will prove most effective. Each has developed his own technique, and each technique is the correct one. But in color work, as in black and white, there are a few fundamental rules which can be laid down for the photographer. First and most important of these is exposure. The old rule of "expose for the shadows, the high-lights will take care of themselves," will not hold for accurate color work. There are two negatives to consider, and highlight and shadow are to be transformed ultimately into color on the screen. A sacrifice to either, regardless of how slight, and notwithstanding the latitude of present day emulsions, will destroy, to some extent at least, a perfect color balance. Therefore, it is necessary to expose correctly, and exactly so, for normal color scenes. In photographing by the Crosene Process, either exterior or interior scenes, any lens may be used. Filters are not necessary in normal work. To calculate for the correct exposure the lens is set as though the scene were being photographed in black and white and then the aperture is increased one-third of a stop. That is all the additional illumination that is necessary, and this method of calculating exposure will insure exact results. In photographing interiors the uniformity of the illumination is of more importance than the amount. In color work definition does not depend on light and shadow. Color, and only color, can define the picture on the screen. Hence, illumination must be uniform throughout the entire scene if the best definition is to be secured. Too much illumination on the set is as bad as too little unless compensation is provided for by stopping down the lens. These few simple rules are the only changes in conventional camera technique which photographing in color by the Crosene Process requires. Special filters for special effects, and special effects without special apparatus necessitates a specialized technique, just as in the case of black and white. The important fact is that any photograph which can be made in black and white can be made as readily in color by the Crosene Process. Now, as to changes in conventional projection technique, the Crosene Process requires even fewer than have been set forth above with respect to camera technique. As has been pointed out previously, the Crosene Process is an additive system, and the four component images embraced within the area of a conventional monochrome frame are passed through their respective color filters and superimposed upon the screen during projection. This is an entirely automatic process insofar as the projectionist is concerned. He merely substitutes the Crosene lens for the conventional black and white lens, which it closely resembles in general shape and size, and focuses the already superimposed images (Turn to Page 24) J \ *s Well Pay Cash! WE WANT IMMEDIATELY Mitchell Eyemo De Brie Akeley Bell & Howell Contax Leica, and Similar Used Cameras — Also — LENSES, MOTORS, PARTS, AND CAMERA ACCESSORIES What Have You To Offer? Write or Wire Today MOTION PICTURE CAMERA SUPPLY, INC. 723 7th Avenue New York City f* Please mention The International Photographer when corresponding with advertisers.