Reduction of Development Sprocket-Hole Modulation--

One of the contributing factors to sound-track degradation is sprocket-hole modulation. This is more commonly known as 96-cycle modulation, and results from non-uniform action of developer around the perforations during the time of processing. Its chief remedy is turbulation. - The practical aspects of controlling the amount of sprocket-hole modulation is described herein. Curves showing the increase of this distortion due to diminished turbulation are included as well as those showing the intermodulation of recorded sound by sprocket-hole agitation. The turbulation method employed at the Film Laboratory of Twentieth Century-Fox Film Corporation at Hollywood is disclosed and the various sensitometric means of control relative to this problem are given.