This was to be effected via an additive process followed by tanning and dyeing the images. It was only a decade later, in 1926, that the two-color movie The Black Pirate, with Douglas Fairbanks, caused a sensation.
To begin with, the processes that Technicolor used during the 1920s only recorded red and green, but the problem of three-color recording was solved in 1932.
The camera was made by the Mitchell corporation, following the instructions provided by J. Arthur Ball of Technicolor. Three 35-mm negative film strips were used. Two camera slots, with clawed synchronized advance mechanisms, intermittently fed the three films to the focus of the lens. This captured the images and sent them to the interior of the camera onto a block of glass, which was made up of two prisms separated by a fine layer of gold that allowed some of the rays of light to pass directly through it whilst reflecting the rest, acting as a 45° mirror.
A green filter allowed the image from the green portion to be recorded on an orthochromatic film in the lens' optical axis. The two images from the blue and red portion were recorded behind a magenta filter, which allowed the red and blue rays of light to pass onto two strips of film, called bipack, with touching emulsions. The first film had an emulsion that was only sensitive to blue and had a colored coating so that it absorbed the blue rays and only let red rays reach the panchromatic emulsion of the second film. In this way a set of three negatives was obtained, one green, one blue, and one red. Eastman provided Technicolor with the three respective emulsions, with the appropriate color spectrums and sensitivities.
Very strong lighting was needed during filming. The camera, which had a noisy motor, needed to be enclosed in an enormous blimp or case. Technicolor demanded that Natalie Kalmus, Dr. Kalmus' ex-wife, be present at every film shoot in the role of "color consultant." Printing using "imbibition" was a complex process. From the three negatives made from the three-color selection, three positive strips were obtained and calibrated. These positive film strips were submitted to a tanning process which hardened the gelatin proportionally to the density of the silver image, so that, after stripping with hot water, raised images remained. From these images, it was possible to print colors. The three positive, raised matrix strips were then soaked with yellow, purple, and blue-green dye. The duplicate (positive developed and fixed after printing the sound track) was successively fed through three machines where it made contact with the dye-imbibed matrices. The contact occurred along a dented ribbon. The matrix and film were applied on a layer of water, with the excess water removed by pressure.
The letter D engraved on the camera designated Technicolor Process Number Four, which had been preceded by three other systems since 1915, all two color. Only 28 Model D cameras were created after 1932, numbered from D1 to D12, then D14 to D29 (D13 was not made due to superstition). Six other modified cameras were made after this, three for animation and three for high-speed films (series E). And of the 28 original D-series cameras, 11 were later modified for use in Technirama and Vistavision.
Despite the success of these cameras—in 1932, Technicolor was awarded a Scientific and Technical Oscar by the Academy—the company went through a period of economic hardship following the economic crisis of 1929. Walt Disney's Silly Symphonies were the first productions to allow them to overcome this hurdle. Pioneer pictures then released La Cucaracha (Lloyd Corrigan) in 1933, then RKO produced Rouben Mamoulian's Becky Sharp in 1935.
Technicolor Ltd was established in London in 1936 under the aegis of Alexandre Korda. It was here that Jack Cardiff agreed to film several of Michael Powell's masterpieces. The Technicolor system made its mark with A Star is Born, Wizard of Oz, and Gone With the Wind.
On 29 February 1940, Dr. Kalmus received an Oscar for his lifetime achievements, presented to him by Darryl F. Zanuck. The dream ended in 1952: The arrival of the Eastman Color monopack brought about the end of three-strip Technicolor. Nonetheless, Technicolor would never stop evolving, and for more than 28 years, the process and its derivatives would receive a technical Oscar [Color Cinematography] almost every three years.