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Trichromatic color vision is the ability of humans and some other animals to see different colors, mediated by interactions among three types of color-sensing cone cells. The trichromatic color theory began in the 18th century, when Thomas Young proposed that color vision was a result of three different photoreceptor cells.
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.. The Young–Helmholtz theory (based on the work of Thomas Young and Hermann von Helmholtz in the 19th century), also known as the trichromatic theory, is a theory of trichromatic color vision – the manner in which the visual system gives rise to ...
Two complementary theories of color vision are the trichromatic theory and the opponent process theory. The trichromatic theory, or Young–Helmholtz theory , proposed in the 19th century by Thomas Young and Hermann von Helmholtz , posits three types of cones preferentially sensitive to blue, green, and red, respectively.
The four pigments in a bird's cone cells (in this example, estrildid finches) extend the range of color vision into the ultraviolet. [1]Tetrachromacy (from Greek tetra, meaning "four" and chroma, meaning "color") is the condition of possessing four independent channels for conveying color information, or possessing four types of cone cell in the eye.
The observer then perceives a cyan (or magenta) square on the blank sheet. This complementary color afterimage is more easily explained by the trichromatic color theory (Young–Helmholtz theory) than the traditional RYB color theory; in the opponent-process theory, fatigue of pathways promoting red produces the illusion of a cyan square. [39]
A dominant theory of color vision proposes that color information is transmitted out of the eye by three opponent processes, or opponent channels, each constructed from the raw output of the cones: a red–green channel, a blue–yellow channel, and a black–white "luminance" channel. This theory has been supported by neurobiology, and ...
The Young-Helmholtz trichromatic theory of color vision postulated that there were three types of photoreceptors in the eye, each sensitive to a particular range of visible light: short-wavelength cones, medium-wavelength cones, and long-wavelength cones. Trichromatic theory, however, cannot explain all afterimage phenomena.
This theory supports the evidence showing that trichromatic color vision originated in Africa, as figs and palms are scarce in this environment thus increasing the need for this color vision selection. However, this theory does not explain the selection for trichromacy polymorphisms seen in dichromatic species that are not from Africa. [22]