A Good Idea At The Time...

NON-PHOTO VARIABLE AREA

JOHN ALDRED

An interesting Dutch invention was a non-photographic recording system producing a variable area sound track. It gave good quality and proved to be extremely popular, especially for direct playback. A special film was used, coated with a highly transparent gelatine layer, which in turn was coated with an opaque layer approximately 0.025mm (0.001in) thick. A stylus similar to that used for disc cutting was arranged to oscillate vertically with respect to the film plane. The very small angle between the cutting edges and the film surface, which is only 3 degrees, produced a hill and dale recording 2mm (0.08in) in width. The result looked like a photographic positive which, due to the extremely sharp edges and the absence of any photographic grain, gave excellent results.

The Philips-Miller variable area direct stylus recording system. S = cutting stylus, Z = filack layer

The name? Philips-Miller. It was used extensively for radio during the 1930s (anyone remember Rinso Music Hall from Radio Luxembourg?), and the quality was every bit as good as a live broadcast on AM radio. In theory it could be copied by printing photographically, but since it lacks any cross modulation characteristics, difficulties might arise. This explains why it did not succeed as a lasting system for motion picture sound.