Applications of Laser Technology to Photographic Optical Sound Recording

Michael Strong, Jack Leahy

Photographic optical sound recording has been used for composite sound tracks on cinema prints since the introduction of sound on motion-picture film. It has evolved through variable-area to variable-density modulation, using various forms of modulators, and back to variable-area, in worldwide use today. The majority of modulators currently in use are light valves and galvanometers, both types capable of stereophonic variable-area recording. Various other modulator schemes have been tried, but few were ever commercially put into service. Today a successful new optical recorder has been developed, using a laser beam that is capable of exposing a sharper image with a more even field and an extended frequency response. This article describes this new technology, which can be used for recording standard stereo variable-area sound tracks, making optical test films, and future recording of digital audio sound negatives.

Print ISSN
Published
1992-01
Content type
Original Research
DOI
10.5594/J02357