Colour mixing based on daylight

Abstract

Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large region of the colour space can be covered by mixing three primary colours derived from lossless spectral decomposition of daylight. These primaries are specified by hue, saturation and luminosity. Duality of additive and subtractive mixing is formulated quantitatively. Experimental demonstrations of calculated results are suggested. This paper is intended for undergraduate optics courses, and advanced interdisciplinary seminars on arts and physics.

Spectral synthesis provides two-dimensional videos on a one-dimensional screen with 360°-visibility and mirror-immunity

“…To obtain the RGB image components, their grayscale versions are inserted in the corresponding intervals (600-700nm, 500-600nm, or 400nm-500nm, respectively; cf. [20]) between AB and CD. However, their superposition requires a specially designed DEA.…”

Basic slit spectroscope reveals three-dimensional scenes through diagonal slices of hyperspectral cubes

“…For three centuries, slit spectroscopes have been used to disperse the image of an illuminated slit into a spectrum of colored slit images [1,2]. In the slit spectrum, each color is monochromatic, representing a specific wavelength of light [3,4]. The wavelength composition allows one to quantify color qualities [1,4], to analyze the chemical composition of substances on earth [5] and in the sky [6,7], and to infer the thermodynamics and kinematics of galaxies [8], stars [9], or even sun spots [10].…”

Maxwell's first coloured light sources: artists' pigments

“…The boundary of Maxwell's colour triangle can be superimposed on to the CIE chromaticity chart (Fig. 5), matching approximately the colours of his artists' pigments -to which we no longer have access -to three of the colours on the chart [6]. This confi rms that the gamut of colours got from combining light from various proportions of vermilion, emerald green and ultramarine is only a fraction of the complete range including other pigments.…”

“…This is how the gamuts of available colours from other choices of standards can still be conveniently represented diagrammatically nowadays (see e.g. Meyn [7]).…”