The art of sound pictures (1930)

COLOR 249 example, done in color photography, might be worth hundreds of thousands of dollars more to the producer if it could be released a week, or even three days earlier. Despite this very great advantage in black and white film carrying latent color values, all of the color processes now being used in pictures require a film which is itself colored. Though there are other types of additive processes, none has received, as yet, the serious attention of the motion picture producers. One or two other types of additive processes may now be explained. Multiple Film Processes Instead of taking three successive color pictures and subsequently projecting them successively on the screen, all three pictures may be taken simultaneously on three separate films. This, of course, might be done by using three different lenses, or three cameras, each with a different colored filter. But such a method would not give three identical pictures, because each separate lens, or each separate camera, would photograph the object at a slightly different angle. Using the same lens, however, prisms may be inserted behind the lens in such a way that three separate images of the same picture can be thrown simultaneously on three separate strips of film. A differently colored filter may then be interposed in front of each of the three separate films. In projecting pictures taken in this way, a corresponding set of prisms, or similar apparatus, must be placed in the projector, and the three differently colored films carrying exactly corresponding pictures in different colors must be precisely synchronized, so that the corresponding pictures are thrown simultaneously on the screen. This is