Colorimetric Purity
The saturation, or degree of paleness of a color, is related to colorimetric purity. The equation for colorimetric purity is: P=L/(Lw+L). In this equation, L equals the luminance of the colored light stimulus, Lw is the luminance of the white light stimulus to be mixed with the colored light. The above equation is a way of quantifying the amount of white light that is mixed with the colored light. In the case of pure spectral color, with no white light added, L equals one and Lw equals zero. This means colorimetric purity would equal one, and for any case involving the addition of white light, the colorimetric purity, or the value of P, would be less than one. The purity of a spectral color stimulus can be altered by adding white, black, or gray stimulus. However, the Abney effect describes the change in colorimetric purity by the addition of white light. In order to determine the effect that changing the purity has on the perceived hue, it is important that purity be the only variable in the experiment; luminance must be kept constant.
Read more about this topic: Abney Effect
Famous quotes containing the word purity:
“Do not be discouraged, if in a thousand instances you find your kindness rejected and wronged, your good evil-spoken of, and the hand you extend for the relief of others, cast insultingly away; the benevolence which cannot outlive these trials of its purity and strength, is not like the self-sacrifice of him, who went about doing good.”
—C., U.S. women’s magazine contributor. American Ladies Magazine, pp. 331-4 (July 1828)