
George Eastman House is the repository for many of the early tests made by the Eastman Kodak Company of their various motion picture film stocks and color processes. The Two-Color Kodachrome Process was an attempt to bring natural lifelike colors to the screen through the photochemical method in a subtractive color system. First tests on the Two-Color Kodachrome Process were begun in late 1914. Shot with a dual-lens camera, the process recorded filtered images on black/white negative stock, then made black/white separation positives. The final prints were actually produced by bleaching and tanning a double-coated duplicate negative (made from the positive separations), then dyeing the emulsion green/blue on one side and red on the other. Combined they created a rather ethereal palette of hues."(via Nag on the Lake)