The Young–Helmholtz theory, also known as the trichromatic theory, is a theory of trichromatic color vision – the manner in which the visual system gives rise to the phenomenological experience of color. In 1802, Young postulated the existence of three types of photoreceptors in the eye, with different but overlapping response to different wavelengths of visible light.
Thomas Young and Hermann von Helmholtz assumed that the eye's retina consists of three different kinds of light receptors for red, green and blue
Thomas Young FRS was a British polymath who made notable contributions to the fields of vision, light, solid mechanics, energy, physiology, language, musical harmony, and Egyptology. He was instrumental in the decipherment of Egyptian hieroglyphs, specifically the Rosetta Stone.
Portrait by Henry Perronet Briggs, 1822
Plate from "Lectures" of 1802 (RI), pub. 1807
Volumes I and II of A Course of Lectures on Natural Philosophy and the Mechanical Arts (1807)
Title page to volume I of A Course of Lectures on Natural Philosophy and the Mechanical Arts (1807)