Color constancy refers to the relatively stable appearance of objects despite changes in context.
For example, the light reaching the eye from an object can be altered due to illumination changes, yet the object's color appearance tends to remain stable. We appear to be reasonably color constant under a range of different illuminants. However, it is still an open question whether we have the same degree of color constancy across all types of illuminant changes. Another example of color constancy occurs across changes in mutual reflections . This type of constancy has not received much attention and it is not clear to what degree the visual system maintains constancy under these conditions.