Color matching

An observer adjusts lights until they appear to match a comparison under specified viewing and adaptation conditions. The settings and range of accepted matches constrain the available spectral signals. Matching differs from detecting a difference and from assigning a color name.

A match between a mixture of two long/middle-wave lights and a comparison light, with mixture ratio and brightness separately adjustable. The settings and acceptance range help characterize red–green color-vision variation. A satisfactory brightness match alone is not evidence for normal chromatic discrimination.