International projectionist (Jan-Dec 1935)

28 INTERNATIONAL PROJECTIONIST April 1935 I«A« Members Know what Real Cooperation is! WITH its vast facilities in the manufacture and supply of motion picture sound equipment, both new and renewed, S.O.S. has already afforded locals throughout the country a most valuable service in supplying replacement parts and general equipment — bringing amazing savings to each theater. We stand eager to supply all theater requirements on short notice and at lowest prices in the industry. Recognised internationally as the World's Largest Mail Order Supply House. S.O.S. . equipment is operating in over 8,000 theaters. A Bona Fide Guaranty goes with every order. Catalogs and prices supplied free on request. Write us your problems. S.O.S. Corp., 1600 Broadway. New York. N. Y. Your Preference — Please We solicit your aid, Mr. Reader, to the end that International Projectionist may render the maximum service to its readers. You can help to improve this service by stating your preference for editorial matter. What type of articles, drawings, photographs and features do you prefer? Use the space below to record these preferences. We'll do the rest. USE THIS FORM Editor, INTERNATIONAL PROJECTIONIST Sir: I should like to have published in INTERNATIONAL PROJECTIONIST articles (or drawings) relating to the following subjects: 1 2 3 4 Name Address imately placed in position. Plenty of gobos are on hand to shade the screen from light striking the foreground. A projected picture of the approximately correct size is thrown upon the screen. If the size is not satisfactory, lenses are changed, or the projection machine is moved to attain the desired result. Then the lighting is balanced by measuring first the light striking the foreground, and then the intensity of the projected light. The measurements are made with the Weston photronic meter. A final photographic test is made as follows: The foreground is illuminated, an interlocking phase is switched on, and the camera shutter is set to a standard position. Then the clutch of the projector is closed in the corresponding shutter-synchronizing position, and the projector and camera are operated synchronously for about 30 feet of film. From the end of this test-exposure two feet are developed and fixed by hand, and then enlarged on paper so as to show what changes might be required. After obtaining a good test, the scene is finally photographed and recorded. In conclusion, the author expresses his sincere appreciation to Messrs. L. W. Davee and H. Griffin who cooperated in making this background projection process a success. Discussion: Chairman Crabtree: In the scene where the girls were seated on the parapet and the boys were going through their antics in front of them, the girls didn't seem to be in the least interested in what the boys were doing. Obviously, if there are any animate objects in the picture when the background scene is shot, they ought to be doing what you intend them to be doing in the composite picture. How are screens made? Originally ground glass was used, but I understand that most screens consist of fabric sprayed with, say, cellulose acetate or some similar transparent material. Mtj. Popovici : I can not give you any definite information on cellulose screens, because we used only the Fox screen, which, so far as I know, is made by spraying certain materials upon a flat plate of glass, and then peeled and processed in a secret way. As regards the Trans-Lux screen, which was used on the shots you saw today, it is silk impregnated with gelatin with a little color pigment in it. The gelatin is pressed against a matte surface in such a way as to provide a high diffusion factor. The transmission of the screen is, however, very low : the one we have used so far transmits only 17 per cent of the light. The viewing angle decay is very, very small, even enabling us to make shots when running with a camera from the side, or in and out, without difficulty or without any difference of density in the re-photographed image. On the Fox screen, however, the slight