Journal of the Society of Motion Picture Engineers (1930-1949)

on existing playback and editing equipment. The RCA type RT-11A magnetic tape recorder was built for professional service and is being used widely in the broadcasting and television fields. It has also found limited acceptance in motion pictures for recording projection takes. Comparatively little use was made of 16-mm magnetic film although recorders were available. Reeves Soundcraft Corp. introduced a service for edge-coating 16-mm raw stock or developed film with magnetic material to permit the use of magnetic sound tracks with 16-mm prints. Excellent sound reproduction from such prints was demonstrated at the fall convention using a modified projector. J. A. Maurer, Inc., demonstrated a new multiple-track 16-mm sound-recording system that reduces distortion resulting from nonuniformity of the projector sound-scanning light beams. The Magnagram Corp. of North Hollywood, Cain0., has announced a new subminiature field unit, the F-102 magnetic film recorder. Available in 16 mm or 17^ mm, the unit is light in weight (38 Ib for two cases) and extremely compact. Film capacity for either is 400 to 1200 ft of magnetic stock. 35-Mm Picture and Sound Reproduction The activities of the Screen Brightness Committee in obtaining accurate information on a group of 100 theaters throughout the country has already had an effect on the motion picture studio laboratories where the preliminary information is being used to determine if changes should be made in print density. In at least one studio it was found desirable to increase set lighting levels slightly in order to improve the projection quality of the prints. This work promises to bring about a much better correlation between produc tion and exhibition both as to print quality and projection conditions.28'29 At least two new mirror-type carbonarc projection lamps have been described. These units feature fast optics, arc-positioning devices, forced air control of exhaust gases and new methods of automatic arc control. 30>31-32 In the field of control of heat in the projection optical train, there have been a number of installations of units with heat-absorbing glass filters and others with compressed air blowing against the film. In addition, considerable work is being done experimentally and in field tests with treated mirrors and optical train filters of the interference type.33 A new all-plastic screen made of Firestone "Velon" plastic and known as RCA Snowhite Evenlite vinyl screen is illustrated in Fig. 6. The material is 0.012 in. thick, weighs % psi and is said to be sag proof. It is pigmented with titanium dioxide and surface embossed for high efficiency and diffusion. It is also flameproof, mildew proof and unaffected by heat, cold or moisture. The surface is rugged and can be cleaned by washing, soft brush or vacuum cleaner. A new Walker high-intensity screen is made of plastic in which no vinyl is used. The metallized surface is made up of elliptical forms which spread the light fanwise to control reflection. It is recommended for theaters with wideangle viewing conditions, but with no more than a 12-deg projection angle. It is claimed that the control of stray light improves contrasts and results in better apparent definition. Cinerama, a system of exhibiting three frames of film in a curved panorama, has been demonstrated. It is stated that, while the inventor does not claim stereoscopic results from a strictly technical standpoint, the effect is one of super reality. The system includes the use of several sound tracks for projection of stereophonic sound.84 Progress Committee Report 575