the tendency for a color to look the same under widely different viewing conditions
The psychology tendency to see colors as we think they are rather than as we actually perceive them (Zelanski).
Stability in the perceived color of a surface across changes in illumination and the consequent changes in the light reaching the eye.
The tendency to perceive inaccurate nature-specific and object-specific colors as true is color constancy. Some examples of these 'memory' colors are: eggshell white, fire-engine red, lemon yellow, and sky blue. Skin tones also come under color constancy. When a printed image is viewed individually the color looks correct, when we compare the accurate flesh tone to the inaccurate color then the color difference becomes evident. In addition to these other aspects, the eye is most sensitive to colors in the middle of the spectrum. Given equally intense colors, midspectrum colors such as green appear brighter than the endspectrum colors of red and blue.
The tendency to see a familiar object as of the same color, regardless of changes in illumination on it that alter its stimulus properties. See also perceptual constancy.
Color constancy is an example of subjective constancy and a feature of the human color perception system which ensures that the perceived color of objects remains relatively constant under varying illumination conditions. An apple for instance looks green to us at midday, when the main illumination is white sunlight, and also at sunset, when the main illumination is red. This helps us identify objects.