Journal of the Society of Motion Picture and Television Engineers (1950-1954)

In France renewed efforts were made by inventors to dispense with viewing glasses, and effect image separation at the screen. The number of 3-D productions which have been planned virtually overnight and distribution and exhibition of these productions has presented complicated and very serious problems of standardization. Since three-dimensional pictures of the Polaroid-viewing type of necessity require two projectors to be running simultaneously, the problem of reel sizes for the minimum number of change-overs and intermissions becomes very acute. It has been necessary to set up committees to establish at least temporary standards for reel sizes, screen sizes, screen types, projector interlocking mechanisms, designation of right and left films, allocation of sound track to a specific film, and improved light sources. The problem of light loss in projection through Polaroid filters is very acute. Approximately 60% of the light is lost. Sound Recording Magnetic recording became the established medium for original dialogue and music recordings throughout the motionpicture industry in 1952. Those studios which attempted to extend the use of magnetic recordings to the motion picture editor's work found it necessary to provide some form of visual modulation aid. One generally accepted method for doing this is through the use of a combination photographic-magnetic sound track. As this would imply, the film carries both a photographic sound track of either the negative-positive or directpositive types and a magnetic sound track recorded on a narrow strip or stripe of magnetic material located on the opposite edge of the film. This has naturally increased the popularity and demand for the so-called Magna-Stripe film, and for dual photomagnetic recording equipment.10 The Westrex Photomagnetic Recorder illustrated in Fig. 1 records collinear 200-mil push-pull direct-positive variable-area and magnetic tracks. Such a track combines the advantages of a photographic track for editing and the superior quality of magnetic track for re-recording. Another type of visual aid has been provided by the "Sound Scribing" method. One form of this consists of an ink trace of the sound modulation scribed on the film base adjacent to the magnetic track. Another method perfected by the Glen Glenn Studios in Hollywood, involves actually engraving a variable-area type track in an auxiliary or loading stripe by means of a diamond cutter closely resembling a "hill and dale" disk recorder. This engraved track can be clearly seen and reproduced on a 35mm moviola. This method has been used in the production of the popular television shows / Love Lucy and Our Miss Brooks, produced by Desilu Productions. Those studios which do not use the visual aids mentioned above provide the editor with a photographic copy of the original magnetic recording. Methods for recording both variable area and variable density directly from magnetic film for intra-studio use were described.12-13 The transfer from magnetic to direct positive is the most economical. This method is used in the Warner Bros. Sound Department, where the direct-positive editor's track is also used as a re-recording track after having been given a hard protective coating by the Protising Process. A cross-modulation compensator was introduced by RCA in 1952 for use in the production of direct-positive variablearea recordings. This device is introduced in the audio transmission system of a recording channel and will counteract cross-modulation products produced by other parts of the system, such as the emulsion in a photographic variable-area track. In general, this device generates distortion products equal in amplitude and opposite in phase to those contributed by the film emulsion, so that when George R. Groves: Progress Committee Report 537