Editing Color vision (section)

=== Hue detection ===
Sufficient differences in wavelength cause a difference in the perceived [[hue]]; the [[just-noticeable difference]] in wavelength varies from about 1&nbsp;[[nanometer|nm]] in the [[blue-green]] and [[yellow]] wavelengths to 10&nbsp;nm and more in the longer red and shorter blue wavelengths. Although the human eye can distinguish up to a few hundred hues, when those pure [[spectral color]]s are mixed together or diluted with white light, the number of distinguishable [[chromaticity|chromaticities]] can be much higher.

In very low light levels, vision is [[scotopic]]: light is detected by [[rod cell]]s of the [[retina]]. Rods are maximally sensitive to wavelengths near 500&nbsp;nm and play little, if any, role in color vision. In brighter light, such as daylight, vision is [[photopic]]: light is detected by [[cone cell]]s which are responsible for color vision. Cones are sensitive to a range of wavelengths, but are most sensitive to wavelengths near 555&nbsp;nm. Between these regions, [[mesopic vision]] comes into play and both rods and cones provide signals to the [[retinal ganglion cell]]s. The shift in color perception from dim light to daylight gives rise to differences known as the [[Purkinje effect]].

The perception of "white" is formed by the entire spectrum of visible light, or by mixing colors of just a few wavelengths in animals with few types of color receptors. In humans, white light can be perceived by combining wavelengths such as red, green, and blue, or just a pair of [[complementary color]]s such as blue and yellow.<ref>{{cite encyclopedia | vauthors = Davson H, Perkins ES | title = Human eye | url = https://www.britannica.com/science/human-eye | encyclopedia = Encyclopedia Britannica | date = 7 August 2020 }}</ref>