Complementary colors: The structure of wavelength discrimination, uniform hue, spectral sensitivity, saturation, chromatic adaptation, and chromatic induction

Abstract

Complementary colors have long been thought important to color vision due to their ability (as admixed pairs) to extinguish all chromaticity, and to adapt automatically (i.e., wavelength pairs and radiant power ratios) to illuminant. Their role in color mixture and chromatic induction is well documented but other roles have not been demonstrated. This article studies the structure of complementary colors in the wavelength and radiance dimensions over the hue cycle (the nonspectrals are represented by a nominal-wavelength metric). In the wavelength dimension, the basic structure of complementary colors is the complementary intervals ratio (ratio of a wavelength interval to its complementary interval of 1 nm). The ratio has RGB peaks, complementary CMY troughs, and provides models of chromatic induction, wavelength discrimination, and uniform hue difference in good agreement with data. Novel analyses of six color order/UCS hue circles indicate essential characteristics of a uniform hue scale. In the radiance dimension, basic structure is the complementary powers ratio (power of a stimulus required to neutralize its complementary of 1 Watt). The inverse structure has RGB peaks, complementary CMY troughs, and provides models of saturation, spectral sensitivity, and chromatic adaptation to illuminant. The RGB peaks demonstrate spectral sharpening, implying a postreceptoral location in the physiology. The models indicate that complementary colors have a significant role in color appearance besides their well known role in color mixture.

Relative wavelength metric for the complete hue cycle: Derivation from complementary wavelengths

“…These peak wavelengths are almost constant with illuminant (the R peak shifts the most, as 607 nm 6 1 nm), indicating a particularly stable function. The peaks for illuminant D65 are 445.5 (B), 531.5 (G), and 606 nm (R), 7 or 160.5 nm overall interval, representing 80.25 nm mean intervals from B to G and from G to R. Assuming the same interval for the third interval from R to B gives a total 240.75 nm hue cycle interval. The mean of the four methods is 241.4 nm, say 240 nm relative wavelength as a round figure.…”

“…Open-diamond points are wavelength and nonspectral complementary, e.g., 530 nm and 530 c; the latter is correct numerically but their locations on the axes are estimates; i.e., the indicated complementary wavelengths were chosen to fit the labeled 10 nm intervals (in the linear scale) to give a smooth curve (and to match CI ratios in Ref. 7). Two asterisks represent the complementary pair 529 nm and 529 c (hue cycle midpoint and hue cycle ends, at 409 and 649 nm equivalent wavelength), representing 240 nm hue cycle interval.…”

“…On this basis, this article formulates the structure of complementary wavelength pairs in the spectrum and extends the structure and numerical (wavelength) series into the nonspectrals, thus deriving a wavelength-based scale for the entire hue cycle, for use with CIE illuminant D65 and 2-48 visual field. The method was largely developed in previous articles over some years, [5][6][7] integrated and amplified here as a stand alone paper. Later below, data are specified (in the following article) 4 to extend the use of the wavelength-based metric to some other CIE illuminants and to the 108 visual field.…”

Complementary colors theory of color vision: Physiology, color mixture, color constancy and color perception

“…The hue cycle is isomorphic in varying illuminant for ease of chromatic adaptation. 16,17,18 The symmetrical cycle structure is centered on the complementary wavelength pair of minimum complementary interval (MCI) found from CIE data; its mean wavelength gives the hue cycle midpoint (e.g., 529 nm for illuminant D65; Fig. 1), which shifts wavelength with illuminant (Fig.…”

“…The relative wavelength scale is used to complete the most basic functions of complementarism 16,17 thought to exist in the physiology: the ratio of complementary wavelength intervals [see Fig. 3 24 The black solid curve is a model of saturation discrimination for uniform radiance.…”