Will the real units of Q please stand up?

Abstract

There exists a general misunderstanding among colorists as to the units involved in the equation for tristimulus integration. The investigator of the color-matching functions chooses four cardinal stimuli which, along with his choice to cause the three primaries to have equal coloration power to each other, causes him to assign units to the color-matching functions in order that these units may be carried to the equation for tristimulus integration. This note discusses the development of these units using the 1931 RGB experiment and subsequent algebraic processing as an example. It develops exactly what these units are and concludes that they are consistent.