\-^¦me-tə-_¦mer-ik-\. A pair of colors, which appear to be identical to all observers under all conditions of illumination and viewing; an unconditional match. Popularly, the term is frequently used to apply to a pair of colors, which has identical spectrophotomeric reflectance or transmittance curves, as measured in a prescribed geometric configuration, thus ignoring the effects of any differences in geometric characteristics between the samples in the pair. In practice, the term may be used to describe a pair of samples, which does not appear to change in comparison to one another when viewed under several different light sources.

See metamerism. Also known as a non-conditional match.