Adams Chromatic Valence Color Space - Chromatic Value

Chromatic Value

In 1942, Adams suggested chromatic value color spaces. Chromatic value, or chromance, refers to the intensity of the opponent process responses, and is derived from Adams' theory of color vision.

A chromatic value space consists of three components:

• the Munsell-Sloan-Godlove value function:
• , the red-green chromaticity dimension, where is the value function applied to instead of Y
• , the blue-yellow chromaticity dimension, where is the value function applied to instead of Y

A chromatic value diagram is a plot of (horizontal axis) against (vertical axis). The 2½ scale factor is intended to make radial distance from the white point correlate with the Munsell chroma along any one hue radius (i.e., to make the diagram perceptually uniform). For achromatic surfaces, and hence, . In other words, the white point is at the origin.

Constant differences along the chroma dimension did not appear different by a corresponding amount, so Adams proposed a new class of spaces, which he termed chromatic valence. These spaces have "nearly equal radial distances for equal changes in Munsell chroma".