Chromatic Adaptation

Have a look at the photo of the dinosaur Bix on the right in the photo below. The colors are split down the middle, with a cyan cast on the left half and a yellowish cast on the right.


Now stare for 20 seconds at the little “+” on the line between the color fields on the left. (Click on the whole image to make it bigger.)

When you look back at the "+" on the nose of Bix, the color distortions disappear and Bix looks normal, at least for a while.

This is a demonstration of chromatic adaptation, our visual system’s “white balance” control. Whenever the illumination changes in color temperature around us, the sensitivity of our color receptors changes in relative proportion, resulting in a balanced impression of color.