American cinematographer (Jan-Dec 1931)

June, 1931 AMERICAN CINEMATOGRAPHER Seventeen jection is accomplished through a lens similarly equipped with three apertures, covered with red, green, and blue filters. The original negative, made into a positive by a process of photographic reversal, is used for projection. There is but one film available, but this is all that is necessary for the use in television which we are considering. The film is cheap as compared to a film in which the color is added by a dyeing process, and the time required to prepare it for projection is a matter of hours instead of days. T P' p Fig. 3 The method of using Kodacolor film may be most comprehensively described by saying that the film is to be projected as though for display upon a screen, but that the three beams of light issuing from the projection lens are directed each into a separate photoelectric cell for television transmission. With the details of the apparatus shown in Fig. 1 in mind, the Kodacolor film arrangement is readily grasped from Fig. 3, where the upper view (a) shows the elevation, the middle view (b) the plan, and (c) shows a detail of the scanning disk and film. Starting with the light source A, the light is condensed by the condenser system C on the film F which moves continuously past the slot S and directly behind the disk D. The disk is shown as provided with radial slots R, these together with the fixed slot S forming the scanning holes. After passing through the film and disk the light is projected as if to a screen by the lens L, in front of which is placed, in the regular projector, the set of red, green, and blue filters T. For our purpose both the screen and the filters are dispensed with. After passing through the lens, the light is diverted into three photoelectric cells, Pi, P2, and P3, by the mirrors M. These cells are all similar, and need not be color-sensitive. The filters are omitted as obviously unnecessary — color is not needed until the signals are received and recombined at the receiving disk where the same apparatus is used as for the reception of signals from original colored projects. The arrangement of apparatus shown in Fig. 3 calls for the slot, film, and disk being practically in contact. This condition, which must be met if color fringes are to be avoided, is likely to offer some difficulty, since both are moving at high speed. An alternative arrangement, by which the disk and film are separated, is shown in Fig. 4. Here the symbols are as in Fig. 3, and the apparatus is the same from the lamp A to the film F. The disk is, however, removed to a new position beyond the projection lens U, which is supplemented by a shortfocus lens Lj so that an image of the film F, where it lies over slot S, is projected onto the disk. A third lens U, close to the disk, images the three apertures T onto mirrors M and photoelectric cells P as before. By this means the film image may be placed accurately in the plane of the disk and color fringes avoided.1 Additional advantages are that the disk may be made of any convenient size, and that the radial slots to which one is practically driven by constructional difficulties in the very small disk may be replaced by holes as shown at (c) . In describing the apparatus for achieving television in colors by a beam-scanning method' emphasis was placed on the fact Fig. 4 that the same single scanning disk was used at each end as for monochrome work. A similar characteristic holds for the film apparatus here described. Either color or monochrome film can be used interchangeably, the latter requiring but one transmission channel. If monochrome receiving apparatus only is available when multichrome film is used, it may be received as monochrome, preferably selecting the green channel as giving nearly orthochromatic effects. If three-color receiving apparatus is available of the form previously described1, images from monochrome film may be received on all three (red, green, and blue) lamps together, adjusting their relative intensities to give white or any other desired color for the resulting monochrome image. References 1 Ives, H. E.: "Television in Color by a Beam-Scanning Method," lour. Opt. Soc. of America, 20 (January, 1930), No. 1, p. 11. Photographic Journal (September, 1929), p. 402. 3 The disk and film could be similarly separated in the form of apparatus shown in Fig. 1 although the necessity is not so apparent. (The above article appears here through the courtesy of The Journal of the Society of Motion Picture Engineers — Editor.) New Natural Color Idea Discovered in England ANEW process for the production of motion pictures in natural colors and printed on non-inflammable film has been discovered, according to the producers, who have shown samples of the film to the Royal Society, premier scientific body of England. It is claimed that the natural color is produced on a film base printed with a foundation, or matrix, consisting of a half-million minute red, green and blue squares to every inch of film. Over this foundation, is a coat of highly sensitive emulsion. Consolidation CONSOLIDATION of the Warner Bros, and First National production department, with Darryl Zanuck as executive in charge of both companies, is announced by Jack L. Warner. Hal Wallis and Lucien Hubbard will be associate executives, while C. Graham Baker heads the scenario department.