 Kodachrome film was coated with three layers of ordinary black-and-white silver halide gelatin emulsion, but each layer was made sensitive to only one-third of the spectrum of colors—in essence, to red, green or blue.Special processing chemistry and procedures caused complementary-colored cyan, magenta or yellow dye images to be generated in these layers as the black-and-white silver images were developed.After they had served their purpose, the silver images were chemically removed, so that the completed chromogenic film consisted solely of the three layers of dye images suspended in gelatin.