Nature Colour/Cinecolor type: 2 colour analysis on 2 separate films/ subtractive print on double coated toned film.

Typically, these films were exposed in a special camera designed to handle two films in the same gate, or two films exposed to the same image by a beam splitter. The two films, often sold as “bipack” by several manufacturers, produced separation images corresponding two the different sensitivities of the films or filters used were records of blue or blue green and orange, the 2-colour primaries. The resulting separations were printed onto double coated or “duplitized” [USA term] print film, one separation on each side, and the silver images toned or dyed blue-green one side and orange the other.

There were innumerable variations in dyeing, film sensitivities and camera mechanisms, some of which became defined by trade names. The first use was probably about 1917 and the last about 1948! One of the early Technicolor systems fell into this category. The first Technicolor, called Technicolor bipack or bichrome, was introduced before 1920. It was based on two negatives exposed through red and green filters, which were printed on two black and white films, then toned in cyan and magenta and finally glued together. This system was used in several films, starting with “The Toll of the Sea” in 1922.