Elements of color in professional motion pictures (1957)

graph a color TV picture using a mul- tilayer color film. The film can be cither a color reversal film, which will produce a color positive kinescope recording, or a non-reversal color film, which will produce a color nega- tive kinescope recording. Interestingly enough, it makes little difference to the television system whether it "sees" a negative or a positive image, for by the simple flick of a switch, TV can make a positive image out of a nega- tive image electronically. Good, high- cjuality kinescope recordings of color television programs have been made on both 16mm and 35mm multilayer color motion-picture films. These recordings are then reproduced by means of color film scanners. Color Kinescope Recordings on Blaclc-and-White Film We mentioned earlier that the televi- sion industry was experimenting with additive color processes for color re- production. These processes are espe- cially interesting for kinescope record- ing, not only because they use inex- pensive black-and-white film which is ([uickly and simply processed, but also because additive processes are funda- mentally more compatible with the color television system, which, as we have seen, is itself an additive color system. Briefly, an additive motion-picture color process involves photographing ilirough red, green and l)lue filters to produce three black-and-white separa- tion positives. These positives can be obtained by photographing three strips ol film simultaneously, as in the three- strip camera. Or, by means of a spe- cial optical device, a red, a green and a blue image may bo reduced in size and fitted intf) the approximate area of a single 35mm frame. This latter system, of course, requires only one strip of film. In either case, separation j^ositives may be made by exposing onto black-and-white reversal film which yields the separation positives directly, or by exposing onto black- and-white negative film and printing separation positives. To reproduce the original color scene, these black-and-white positives are projected with red, green and blue light, and the light which passes through the three images is combined to yield an additive color reproduc- tion. If the three-strip system is used, some means must be provided for regis- tering the three strips exactly. With the single-strip system, the images are recombined by a special optical device similar to the one used during pho- tography. The single-strip system re- (juires a dimensionally stable film, and produces on 35mm film a picture which is less sharp than a 35mm three-strip system. The fundamental reason for the difference in sharpness lies in the fact that, since all three records are reduced in size to fit into the approxi- mate area of a 35mm frame, we have in effect a 16mm rather than a 35mm print. But because the television pic- ture is small compared to a theater picture, this difference in sharpness may not be significant. Lenticular Film A method of producing color mo tion pictures by means of a single strip 1)1 black-and-white film is the use of lenticular film. Novel, but i)y no means new. len- ticular film is a single black-and-white emulsion coated on a base which has been embossed on the non-emulsion side with a structure ol tiny half (ylinder-shaped lenses or "lenticules." These are placed across the film and have a radius of curvature of al)oui 1/500 of an inch. This structure ol lenticules presents an appearance Muuli like a washboard with each indi- \i(Iual lenticule acting as a miniature (vlindrical supplementary lens. 93