The three-strip Technicolor process used three strips of black-and-white film (hence the "three-strip" designation) and a beam splitter[?] or split-cube prism. The prism split the light into three components: greed, red, and blue. The green component was registered onto a strip of panchromatic black-and-white film; the blue was registered onto a strip of red-emulsion-coated black-and-white film; and the red was registered onto another strip of red-senstive panchromatic black-and-white. The red and blue strips were mated back-to-back, in a "bipack" arrangement, with the blue-sensitive film in front.
To print the film, each colored strip had a "relief-positive" print struck from it, which was then bleached to remove the silver and then soaked with a dye that was the exact chromatic opposite of the color in question: cyan for red, magenta for green, and yellow for blue.
Each of the three dye-soaked strips were brought into contact with a single clear strip of film, with each color built up in a successive pass. Such a process is referred to as dye transference[?], which was commonly used in conventional offset printing[?] or lithography but which the Technicolor process adapted to film. The final strip of film would have the dyes soaked into it and not simply printed onto its surface, which produced rich and deeply saturated color.
Sometimes the clear film would be pre-exposed with a composite panchromatic black-and-white positive image derived from the other three negatives, as a way to deepen the blacks and heighten the contrast of the image.
Technicolor originally existed in a two-strip (red and blue/green) system, and then as a subtractive color system where the color inforation was carried directly onto the film and not projected through filters.
With the advent of single-strip color film in the Fifties and Sixties, Technicolor eventually fell out of favor in the United States as being too expensive. In 1975, the last three-strip plant was closed and sold to Beijing Film and Video Lab in China; a great many films from China and Hong Kong have since been made in the Technicolor process.
The Technicolor company later became involved in video and audio duplication (CD, VHS and DVD manufacturing) and digital video processes. In 1997 they reintroduced the dye-transfer process to film production.
The company was purchased by Thomson Multimedia in 2001.