Selected historical facts

Today's color models are the result of three centuries of argument about what color is. Some questions were settled by physics, some by physiology, and some only by measurements on thousands of observers.

Light and the spectrum

Isaac Newton, between 1666 and 1672, split sunlight with a prism and showed that white light is a mixture of colors, not pure brightness that the prism "tints". In "Opticks" (1704) he arranged the spectral colors on a circle, joining red to violet. Newton's circle is the ancestor of the hue angle in HSV and HLS.

Johann Wolfgang von Goethe, in his "Theory of Colours" (1810), opposed Newton. His physics did not hold up, but his descriptions of sensations, colored shadows and contrast started the psychology of color.

Three receptors

Thomas Young suggested in 1802 that the eye cannot have a separate receptor for every color and that three kinds would be enough. Hermann von Helmholtz developed the idea in the 1850s. The Young-Helmholtz theory, trichromacy, proved correct: a century later three kinds of cones were confirmed (see the model of the eye).

Hermann Grassmann formulated the laws of color mixing in 1853, still the basis of colorimetry: color has three dimensions, and mixing lights behaves linearly (see color mixing).

James Clerk Maxwell measured color matches with spinning disks and a box of spectral colors between 1855 and 1860, and in 1861 presented the first color photograph: a tartan ribbon made from three photos taken through red, green and blue filters. It was the first practical RGB synthesis.

Opponent colors

Ewald Hering noticed in the 1870s that nobody sees a "reddish green" or a "yellowish blue" and proposed the opponent-color theory. For a long time it was seen as a rival to Young and Helmholtz. Today we know both are true at different stages: the cones work trichromatically, and later processing in the retina and brain works in opponent pairs. The a* and b* axes of CIELAB are a direct trace of Hering.

Systems and standards

• 1905: Albert Munsell publishes a color system based on hue, value and chroma, arranged in perceptually equal steps. Still used in geology and industry.
• 1913: the International Commission on Illumination (CIE) is founded.
• 1928-1931: William David Wright and John Guild measure color matches. From them the CIE sets the CIE XYZ model and the 2° standard observer in 1931.
• 1942: David MacAdam shows that XYZ is not perceptually uniform (MacAdam ellipses).
• 1953: NTSC color television in the US introduces the YIQ model, compatible with black-and-white sets.
• 1964: the CIE adds the 10° observer.
• 1976: the CIE adopts CIELAB and CIELUV and the u'v' chromaticity diagram.
• 1978: Alvy Ray Smith describes the HSV and HSL models for computer graphics.
• 1993: the ICC consortium and the color profile format are created (see color management).
• 1996: HP and Microsoft propose sRGB as a common space for monitors and the web.
• 2001: the CIE publishes the CIEDE2000 color difference formula.
• 2020: Björn Ottosson publishes Oklab, a simpler perceptual space that quickly reaches CSS.