Western Electric Co Ltd 16” single sided disc. Interworld Films 532, catalogue number FRS1728. Columbia Graphophone Co Ltd

Sound-on-disc is a sound film processes using a phonograph or other disc to record or play back sound in sync with a motion picture. Early sound-on-disc systems used a mechanical interlock with the movie projector.

The Columbia Graphophone Company Limited was one of the earliest gramophone companies in the United Kingdom, founded in 1917 as an offshoot of the American Columbia Phonograph Company. In 1925 it acquired a controlling interest in its American parent company to take advantage of a new electrical recording process. In 1931, Columbia Graphophone in the UK merged with the Gramophone Company (which sold records under the HMV label) to form EMI.