Tristimulus

Part of speech: noun

Definitions

1. A term used in color science to refer to a three-dimensional set of values representing color perception in terms of red, green, and blue components
2. Referring to a system or model that quantifies color using three primary color components, often in the context of color matching
3. Describing a method for specifying colors based on three distinct parameters that correspond to the human visual response to light wavelengths

Etymology: "Tristimulus" is a technical coinage built from two parts: the Latin prefix "tri-", meaning "three", and "stimulus", a word the English language borrowed directly from Latin, where it meant "goad" or "prick" and was used for a sharp instrument driving an animal forward. In the sense relevant here, a stimulus is whatever excites a sense organ, so "tristimulus" points to three stimuli that together determine what a viewer sees. The term belongs to colorimetry, the science of measuring color. Human eyes have three types of cone cells, each responding most strongly to a different range of wavelengths, so any color can be matched by mixing three primary lights in suitable amounts. The three amounts that produce a match are the tristimulus values, and a color described this way is specified by these three numbers. The idea behind it is older than the word, but the compound itself is a modern scientific formation, not a term from classical antiquity.

Synonyms: color system, color matching