Chromatic Adaptation

Abstract

Monochrome television screens seen through windows from outdoors at night seem very blue, although when viewed indoors at normal distances their blueness is rarely remarked. This is caused by rapid, nearly complete adaptation of the observer, such that the quality of the illumination that prevails in the observer’s field of view seems colorless and is his criterion for white. Outdoors at night, the prevailing illumination from street lamps or interior lighting seen through windows determines his adaptation and criterion for white. Relative to that criterion, the television screen, seen as a small, distant object, is definitely bluish. But viewed close up, the TV screen dominates our field of view, governs our adaptation, becomes our criterion for white, and (if it is a monochrome set) appears nearly colorless.