Photography

From the invention of photography, most people considered its inability to render color to be an important defect. Many early photographs had color painted on by hand in an attempt to compensate. Those attempting to solve the problem of creating color photographs took their cues from researchers into human vision, who theorized that all colors in nature are made from combinations of red, green, and blue. Thus early attempts to create color photographs centered on making three layers of transparent images, one in each of these colors, and sandwiching them together. Each layer was photographed using filters to block out other colors of light. This resulted in photographs that were foggy with poor color.

In 1904, the first practical method of creating color images, called the Autochrome, was invented by the Lumiere brothers of Lyon, France. Autochromes used a layer of potato starch particles, dyed red, green, and blue, attached to a layer of silver bromide photographic emulsion, all on a plate of glass. They were expensive and required long exposures, but Autochromes had significantly better color and were easier to process than previous methods. By 1916, two other color methods competed with the autochrome. All were considered imperfect, however, because they were grainy, and their color was inaccurate and changed over time. Therefore, with the publishing industry and the public hungry for color photographs, attention turned to subtractive color methods.

The subtractive color starts with white light, a mixture of all wavelengths of light, and subtracts color from it. The process uses a three-layer emulsion of yellow, cyan (a greenish blue), and magenta (a cool pink). When subtracted from white, these colors produce their opposites: red, green and blue. Kodak released a subtractive color film for motion pictures in 1935, and in 1938 a sheet film for photography, while the German Agfa Company released its own variation in 1936. Other companies followed. By the 1940s, color negative roll film for use in 35 millimeter cameras was available.

Two methods are currently used for creating color prints. In the chromogenic method the color dyes are created when the print is processed. In the dye-bleach or dye-destruction method, the color dyes are present before processing. The dyes not needed for the image are removed by bleaching.