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Color contrast and constancy. (A) In any natural scene, the context of two patches identical in spectral intensity and power distribution can make the lightness and color of the patches look different (lightness/color contrast). (B) Same contexts can also make two spectrally different patches look similar (lightness/color constancy). The appearances of the targets in a neutral context are shown below [Reproduced from ref. 1 (Copyright 2003, Sinauer)].
