<P> The first color photograph made according to Maxwell's prescription, a set of three monochrome "color separations", was taken by Thomas Sutton in 1861 for use in illustrating a lecture on color by Maxwell, where it was shown in color by the triple projection method . The test subject was a bow made of ribbon with stripes of various colors, apparently including red and green . During the lecture, which was about physics and physiology, not photography, Maxwell commented on the inadequacy of the results and the need for a photographic material more sensitive to red and green light . A century later, historians were mystified by the reproduction of any red at all, because the photographic process used by Sutton was for all practical purposes totally insensitive to red light and only marginally sensitive to green . In 1961, researchers found that many red dyes also reflect ultraviolet light, coincidentally transmitted by Sutton's red filter, and surmised that the three images were probably due to ultra-violet, blue - green and blue wavelengths, rather than to red, green and blue . </P> <P> Creating colors by mixing colored lights (usually red, green and blue) in various proportions is the additive method of color reproduction . LCD, LED, plasma and CRT (picture tube) color video displays all use this method . If one of these displays is examined with a sufficiently strong magnifier, it will be seen that each pixel is actually composed of red, green and blue sub-pixels which blend at normal viewing distances, reproducing a wide range of colors as well as white and shades of gray . This is also known as the RGB color model . </P> <P> The same three images taken through red, green and blue filters which are used for additive color synthesis may also be used to produce color prints and transparencies by the subtractive method, in which colors are subtracted from white light by dyes or pigments . In photography, the dye colors are normally cyan, a greenish - blue which absorbs red; magenta, a purplish - pink which absorbs green; and yellow, which absorbs blue . The red - filtered image is used to create a cyan dye image, the green - filtered image to create a magenta dye image, and the blue - filtered image to create a yellow dye image . When the three dye images are superimposed they form a complete color image . </P> <P> This is also known as the CMYK color model . The "K" is a black component normally added in ink - jet and other mechanical printing processes to compensate for the imperfections of the colored inks used, which ideally should absorb or transmit various parts of the spectrum but not reflect any color, and to improve image definition . </P>

When did color photography begin to be widely used