Colour films are sometimes duplicated by preparing three separate strips to record the red, green and blue components of the original negative by printing three times on to panchromatic black and white stock through the corresponding colour filters.

From these three separation masters, a colour intermediate negative or inter-dupe may be prepared by printing three times through the same colour filters on to a suitable integral tri-pack colour film stock. Negatives in which the component colours of the original have been separately recorded as black and white images, either on individual strips of film or as successive frames on a single strip.

In two-colour processes, the separation images correspond to the blue-green and red-orange components, but in the more general three-colour systems (refer Colour film) they record red, green and blue.

The original Technicolor process of colour cinematography used separation negatives simultaneously exposed in a special camera, and separation negatives are still sometimes made from original colour reversal films and from colour videotape for projection or duplicating purposes. 1



1 1969, The Focal Encyclopedia of Film and Television Techniques, Focal Press, London, New York