Theoretical chromaticity-mismatch limits of metamers viewed under different illuminants

Spectrally different object colors that match for one illuminant generally do not remain matched when the illuminant is replaced by another. However, all possible colors that match under one illuminant are, with any other illuminant, confined to a region of color space that has a closed boundary. This boundary, called the theoretical chromaticity-mismatch limits of metamers due to a change of illuminant, can be computed by means of a linear-programming technique. The size and shape of the theoretical limits in color space depend on the two illuminants involved and on the color of the metamers. A number of examples are given, and some practical implications of the method are discussed.