The Specification of Colour Appearance. I. Concepts and Terms

TLDR

The paper notes that Part II will discuss how changes in viewing conditions affect colour appearance. The study proposes the perceptual term colourfulness to describe how an area appears more or less chromatic, noting that it generally increases with luminance at a given chromaticity. The authors use the CIE 1976 Colour Spaces to systematize psychometric variables such as metric saturation, purity, and chroma that are independent of luminance, providing formulae for their calculation. The paper outlines concepts for specifying colour appearance, collects corresponding colour terms, lists psychometric and psychoquantitative terms that correlate with perceptual and psychophysical descriptors, and supplies formulae for related psychometric variables.

Abstract

Abstract Concepts necessary for the specification of the appearance of colours are described, and the corresponding colour terms collected. Psychometric and psychoquantitative terms are listed that correlate with the perceptual and psychophysical terms used. The perceptual term colourfulness is proposed to denote the attribute of a visual sensation according to which an area appears to exhibit more or less chromatic colour; for a given chromaticity, as the luminance increases, colourfulness generally increases. For related colours, the CIE 1976 Colour Spaces are used to systematize some psychometric variables that are independent of absolute luminance level, including metric saturation, metric purity, and metric chroma, and formulae are given for calculating their amounts. (In Part II, to appear in the next issue, the effects of changes in viewing conditions will be discussed).