Colorimetry — Theoretical elements

This article is a reworking of the Colorimetry article previously written by Françoise CORNO-MARTIN.

The aim of colorimetry is to specify the color of light sources, as well as that of transparent or diffusing materials (opaque bodies, colored filters).

The basic colorimetric concepts are based on the experimental laws of color equalization of light rays, where the observer's eye acts as a zero device for judging the identity of two contiguous areas. It is to the three types of retinal cones, sensitive only to diurnal light levels, that we owe the colored aspect of sensation.

The mechanisms of color vision are explained using both trichromatic theory, valid at the level of retinal receptors, and antagonistic pair theory, valid at the level of the lateral geniculate bodies (bulges at the posterior end of the brain's optic layer). The colorimetric systems recommended by the CIE (International Commission on Illumination) only take into account the trichromatic aspect when specifying colors.

Readers may wish to refer to the following articles:

"Quantitative optics: Photometry. Colorimetry. Spectrometry" in the treatise Sciences fondamentales ;

"Color and visual appearance: the transparent and the opaque" and "Color and visual appearance: metallic and structural effects" to appear in the treatise Sciences fondamentales ;

"Application of colorimetry to surface color control" in the present treatise ;

"Radiometry. Photometry", "Optical pyrometry" in the present treatise;

"Lighting. Basic data" in the Construction section.