A Photoelectric Film Cuing System

A photoelectrically operated cuing system has been developed which avoids the difficulties associated with lack of standardization on edge-notching of film, increases the ease of changing the cuing marks, and also makes feasible concurrent cuing of both light change and special effects. This system has been applied successfully to a standard Bell and Howell Model J printer. However, the features discussed are general and applicable to any type of film-moving system. Spots of white lacquer between the sprocket holes are illuminated by a small beam of light. The reflected light causes a discontinuity in the photoelectric-tube current which is amplified to operate a relay. The printer exposure channel actuates the normal light-change solenoid while the relay in the effect channel is used to initiate fade-in, fade-out cycles through the medium of a magnetic clutch which engages a rheostat in the lamp circuit. Practical operating experience and detailed mechanical features are described.

Print ISSN

0097-5834

Published

1947-10

Content type

Original Research

DOI

10.5594/J11802