Tartan Ribbon, photograph taken by James Clerk Maxwell in 1861. Considered the first durable color photographic image, and the very first made by the three-color method Maxwell first suggested in 1855. Maxwell had the photographer Thomas Sutton photograph a tartan ribbon three times, each time with a different color filter (red, green, or blue-violet) over the lens.
The three photographs were developed, printed on glass, then projected onto a screen with three different projectors, each equipped with the same color filter used to photograph it. When superimposed on the screen, the three images formed a full-color image. Maxwell’s three-color approach underlies nearly all forms of color photography, whether film-based, analogue video, or digital. The three photographic plates now reside in a small museum at 14 India Street, Edinburgh, the house where Maxwell was born.
|The first color photograph made by the three-color method suggested by James Clerk Maxwell in 1855, taken in 1861 by Thomas Sutton. The subject is a colored ribbon, usually described as a tartan ribbon. (via Wikipedia)|
The three-color method, which is the foundation of virtually all practical color processes whether chemical or electronic, was first suggested in an 1855 paper on color vision by Scottish physicist James Clerk Maxwell.
It is based on the Young–Helmholtz theory that the normal human eye sees color because its inner surface is covered with millions of intermingled cone cells of three types: in theory, one type is most sensitive to the end of the spectrum we call “red”, another is more sensitive to the middle or “green” region, and a third which is most strongly stimulated by “blue”. The named colors are somewhat arbitrary divisions imposed on the continuous spectrum of visible light, and the theory is not an entirely accurate description of cone sensitivity. But the simple description of these three colors coincides enough with the sensations experienced by the eye that when these three colors are used the three cones types are adequately and unequally stimulated to form the illusion of various intermediate wavelengths of light.
In his studies of color vision, Maxwell showed, by using a rotating disk with which he could alter the proportions, that any visible hue or gray tone could be made by mixing only three pure colors of light – red, green and blue – in proportions that would stimulate the three types of cells to the same degrees under particular lighting conditions. To emphasize that each type of cell by itself did not actually see color but was simply more or less stimulated, he drew an analogy to black-and-white photography: if three colorless photographs of the same scene were taken through red, green and blue filters, and transparencies (“slides”) made from them were projected through the same filters and superimposed on a screen, the result would be an image reproducing not only red, green and blue, but all of the colors in the original scene.
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.
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.