Throwing Light on Metamerism—Quantifying the Change in a Colour Match Caused by Change of Illuminant

The article discusses the concept of illuminant metamerism, which is the phenomenon that occurs when two coloured surfaces match under one illuminant but not under another. Quantifying this effect is important commercially, and the convention for measuring it is referred to as a metameric index. The metameric indices could be more useful if they included the effect of chromatic adaptation by the observer.