Modern color film
The first modern ("integrated tri-pack") color film, Kodachrome, was introduced by the Eastman Kodak Company in 1935, using three colored emulsions. Most modern color films, except Kodachrome, are based on technology developed for Agfacolor (as "Agfacolor Neue") in 1936. (In this newer technology, chromogenic dye couplers are already within the emulsion layers, rather than having to be carefully diffused in during development.) Instant color film was introduced by Polaroid in 1963.
Basic color systems
Additive: The colors are added as colored lights. In this system, the most common set of primary colors is red, green and blue (RGB). Maxwell's experiment was of this type, as are screen-plate methods, such as Autochrome. Modern digital photographs seen on a computer monitor are also viewed by addition of light from an RGB phosphor array[clarify].
Subtractive: Colors are subtracted from white light by dyes or pigments. In this system the most common set of primary colors is cyan, magenta, yellow and black (CMYK). Ducos du Hauron made several pictures by this method in the late 1800s.
Several commercial print methods were devised using the subtractive technique during the 1930s (see e.g. Coe, ref 1), for printing from "separation negatives". Kodachrome was the first commercially-available film of this type.
Main types of color film in current use
Color negative film forms a negative (color-reversed) image when exposed, which is permanently fixed during developing. This is then exposed onto photographic paper to form a positive image.
Color reversal film, also known as slide film, forms a negative image when exposed, which is reversed to a positive image during developing. The film can then be projected onto a screen.
Commercial Stationery
没有评论:
发表评论