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

44 FORREST July band of this stain, however, does not correspond to the peak of sensitivity of the cesium photo surface; therefore, it is not so objectionable as a visual inspection of the track might indicate. For reversible-type 16-mm film, the variable-area sound track is preferable and with a track treatment of this kind on reversible color film, the characteristics of the treated track lend it best to the variable-area method. For economical reasons, the procedure and equipment used for treating the film have been worked out to operate in connection with the Ansco color-film processing machines operating at the normal processing speed. The equipment can be used with any type of developing machine providing a uniform steady film flow. A uniform flow of film through the equipment is absolutely essential for satisfactory results. In practice, since it is a reversal process, the sound track on Ansco color duplicating film is exposed from a positive-type track. A recorded track having characteristics favorable for printing on black-and-white reversible duplicating stock will be suitable for printing on Ansco color duplicating film. After printing, the color film is processed in the usual way up to the wash before the color developer. In the middle of this wash, the film is lead out of the wash into the sound-track treating equipment (Table I). In the sound-track-treating equipment, the film is first surface-dried to prevent creeping of the treating solution beyond the area allocated for the sound track. This drying is accomplished by passing the film through air squeegees (Fig. 5) and then into a small drying cabinet (Fig. 6). This drying Fig. 6