Brian R Pritchard Motion Picture and Film Archive Consultant
A three colour subtractive reversal print stock. It appeared in 1934 and was the first three layer colour film that could be processed with minor modifications to contemporary laboratory techniques. It did not require toning, colour development or use of dyes during processing. It used pre-dyed emulsions and dye bleaching.
An illustrated description of the way the processed worked is available as a pdf file. GASPARCOLOR.pdf
Bela Gaspar who invented this system had a number of patents to his credit:
GB415040: GB446392: GB480854: GB483366
The film had to be shot as three colour separations. Here is a test film and a digital reconstruction of three of the frames:
It seems as if sound tracks could be of various colours; also variable area and variable density, here are some samples:
These aresample frames from a Gasparcolor film..
This is Red Box Fantasy by Paul Bianchi in Gasparcolor
Please feel free to contact me if the description is not clear or you have further questions.