International projectionist (Jan-Dec 1956)

Kodak engineers adapt lenticulated-film, additive-color system for fast processing of kinescopes required in rebroadcasting of time-delayed color television programs. Simplified Method of COLOR Kinescope Recording By CHARLES Eastman Koda GROWTH of color TV has created a demand for "quick kines" in color. These are motion-picture records of live TV shows, and they are made at the network facility where the program originates, by photographing TV pictures presented on special picture tubes known as recording kinescopes. The exposed film must be processed and ready for projection in less than three hours after exposure, because it is used for time-zone-delayed rebroadcasting to enable audiences in the eastern and western parts of the country to view the show at the same time of day. Color pictures presented on special high-intensity television screens can be photographed on a typical color film, such as Eastman Color Negative Film, Type 5248. The difficulty comes in processing this film in time for the re-broadcast, because color development is a complex and time-consuming procedure. No Color on Film A new method of color-kinescope recording has been demonstrated at the Eastman Kodak Company research laboratories. This method utilizes 35mm black-and-white film which can be processed simply and quickly to meet the demands of time-zone-delay. Three color-separation images are recorded on the film in black and white. One of these images represents the tonal gradations of the red parts of the subject, the second represents the green parts, and the third image represents blue. In certain other additive color proc H. EVANS k Company esses, three such images are recorded in the form of three individual picture frames. An outstanding feature of the newly proposed method of color-kinescope recording is that all three color-separation images are interlaced on a single 35-mm motion-picture frame. This in accomplished by means of very small plastic cylindrical lenses, called lenticules, which are embossed directly into the surface of the film base. Similar lenticules were employed in the old Kodacolor additive color proc ess for amateur motion pictures, and a similar film for theatre release prints is also available. Although very good color can be obtained by the lenticular additive color process, the big stumbling block encountered in practice is the severe loss of light which occurs during projection because a banded red, green, and blue filter must be placed in the optical system to impart color to the projected picture. The subtractive color processes give a much brighter picture. Filters Not Needed However, the color-TV system is additive, and therefore it is possible to employ an additive film process without filters both in kinescope recording and in subsquently televising the film records. The color TV camera employs beam-splitters and filters to derive red-, green-, and blue-separation pictures of the subject. The corresponding three electrical video signals generated by the TV camera can be used to control three separate kinescopes, and colorseparation images will then appear on the kinescope screens. For kinescope recording purposes, it is not necessary that these screens be, respectively, red, green, and blue. In fact, the best phosphor for all three is one that gives off blue and ultraviolet radiation. If photographs are made of the pictures ap Red channel Blue channel Kinescope recording camera Green\^ J channel FIG. 1. Color-kinescope recording on blue-sensitive embossed film. INTERNATIONAL PROJECTIONIST JULY 1956 21