Most of the following terms and definitions are from International Lighting Vocabulary, CIE Publication No. 17.4. Others are from various standard documents, such as ISO, ANSI, CGATS, etc.

A

Abney s law

An empirical law stating that, if two stimuli, A and B, are perceived to be of equal brightness and two other color stimuli, C and D, are perceived to be of equal brightness, the additive mixtures of A with C and B with D will also be perceived to be of equal brightness. The validity of this law depends strongly on the observation conditions.

absorption

Transformation of radiant energy to a different form of energy by interaction with matter.

adapted white

Color stimulus that an observer who is adapted to the viewing environment would judge to be perfectly achromatic and to have a luminance factor of unity. The adapted white usually varies within a scene.

additive mixture of color stimuli

Mixture of color stimuli acting in such a manner that they enter the eye simultaneously or in rapid succession and are incident on the same area of the retina, or are incident in the form of mosaic which the eye cannot resolve.

aliasing

Output image artifacts that occur in a sampled imaging system for input images having significant energy at frequencies greater than the Nyquist frequency of the system.

alychne

Plane in color space representing the locus of colors of zero luminance. This plane passes through the black point...