Technicolor three-colour 35mm Camera, made by Technicolor Corporation, USA c. 1932. Serial number DE17.

Technicolor, introduced in 1915, is regarded as the finest colour motion picture process. It evolved through four versions, culminating in this three-colour camera, which used a beam splitter behind the lens with red, green and blue filters to record the primary colours on three separate monochrome films. The camera has two film gates. Directly behind, the lens recorded the green separation through a green filter. At right-angles to the lens was laced with two films placed back to back (known as bi-packing) and received light through a magenta (i.e. a combination of red and blue) filter. The film which recorded the red separation was panchromatic, like that used to recorded the green separation, but the other was orthochromatic (i.e. it was sensitive only to blue and green) so it only recorded the blue part of the magenta light. Its base was dyed orange to filter out the blue so that only red light was received by the panchromatic film behind it.

Subsequently, a dye matrix positive was made from each processed negative on bichromated gelatin film. These reproduced all the tones as different levels of hardened gelatin - the highlights were clear of gelatin. These matrices were then dyed with the subtractive primaries, yellow (for blue negative), magenta (for green negative) and cyan (for red negative) and used to print the colour print.

The number DE17 on the camera implies that this was camera No 17 at Denham Film Studios, Buckinghamshire.