Radio age research, manufacturing, communications, broadcasting, television (1941)

LATEST MODEL 16MM. PROJECTORS MOVE ALONG THE PRODUCTION LINE AT RCA VICTOR'S CAMDEN PLANT. light in the form of a sharp line less than a thousandth of an inch wide. In 1932, RCA engineers dipped into the magician's hat of optical science and came up with a radically different sound-reproduc- ing optical system for the RCA pro- jectors. At the heart of the new sound - reproducing system were cylindrical lenses which have the peculiar ability to produce a line image of the incandescent lamp fil- ament directly on the film. The new lenses enabled RCA to get a more uniform image at the film using an economical low-power lamp in its projector. The small lamp could be operated from an oscillator built into the amplifier, producing a high-frequency cur- rent which lights the lamp without flicker. Developed Improved Printer In 1933 and 1934, improved models of the original RCA 16mm sound projectors were placed on the market, and in the latter year, RCA further improved 16mm sound by designing an optical reduction printer that made it possible for film-processing laboratories to make 16mm prints of finer quality from 35mm negatives. In 1935, a novel camera, which would be considered sensational even in a post-war year of won- ders, was introduced to the ama- teur movie markets by RCA. This was the RCA 16mm sound camera, in which pictures and sound were impressed simultaneously on a sin- gle film. But RCA did not rest on its ac- complishment. The search for an even finer "paint-brush" for ap- plying sound to film tracks con- tinued. The trouble with the white light then used was that it pene- trated the film emulsion, and "scattered", spreading the exposure and unduly thickening the fine lines of the sound track. Although this was a real problem in 35mm film recording, it was even more seri- ous in the exacting work of 16mm recording. Finally RCA labora- tories found the solution. This was ultra-violet light, first commercially introduced by RCA in 1936. In- stead of completely penetrating and scattering as white light had done, ultra-violet light was absorbed be- fore penetrating more than a minute distance into the emulsion, localizing the exposure to the exact area struck by the recording light beam. A wonder tool in 35mm sound recording, the benefits to 16mm sound recording were manifold. The quality of 16mm sound was boosted still further in 1938, with the introduction of the "electronic mixer", or "compressor" by RCA. By this method the full range of sound was "compressed" onto the 16mm track making the weak sounds loud enough to be distinct without making the loud sounds of such amplitude as to overload the sound track. Film Damage Reduced At about this same time, RCA engineers broke the back of another problem that had been plaguing the 16mm industry. This was dam- age to film in 16mm projectors. Casting previous threading ar- rangements aside, RCA engineers designed a much simplified thread- ing arrangement and incorporated it in another new projector model. The new arrangement featured large 16-tooth sprockets and the passage of film in wide curves and long flowing lines to end crimping and tearing. In 1942, the RCA 16mm sound projector donned the olive-drab of the Armed Forces and went to war. As models PG-200 and PG-200A, it saw global service with Army and Navy. Improvements in these models included a slipping-clutch take-up which put the proper ten- sion on the film regardless of the amount of film on the reel, thus ex- tending film life. During the war, the unusual re- quirements of field use led to an- other step forward in 16mm sound with the perfection by RCA tech- nicians of the "closed-cavity" loud- speaker, a development that had been simmering on the scientific fire for almost two decades. Rugged conditions imposed on 16mm sound equipment had brought a request from the Army Signal Corps for a loudspeaker that was weather- tight, small in size and capable of improving the radiation of lower tones. Overcoming the problems of cavity resonance, RCA technicians by 1943 had fulfilled the Army's request. This development put the quality of RCA 16mm sound far in front of the field. Batsel Directed the Work The history of progress in 16mm motion pictures is the history of work done by a closely knit group of scientists still functioning as a team in the Advanced Development Laboratories and Design Engineer- ig Section of the Camden plant. At the head of the group is Max Bat- sel, Chief Engineer of the Engi- neering Products Department. In addition to directing the work, Mr. Batsel was a major force in achieving standardization of film in the Society of Motion Picture Engineers and the American Standards Association. As Chief of the Advanced De- velopment Laboratories, Dr. E. W. Kellogg is responsible for the basic studies and work in film motion. In addition, he holds the basic patents on speakers used not only in motion pictures, but in radio and sound-reproduction devices. [RADIO AGE 31]