"Color vision and colorimetry"

Human eyes have color receptors known as cone cells, of which there are three types. In some cases, one is missing or faulty, which can cause color blindness, including the common inability to distinguish red and yellow from green, known as deuteranopia or red–green color blindness.Green is restful to the eye. Studies show that a green environment can reduce fatigue.

The perception of green is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nm. The sensitivity of the dark-adapted human eye is greatest at about 507 nm, a blue-green color, while the light-adapted eye is most sensitive about 555 nm, a slightly yellowish green; these are the peak locations of the rod and cone (scotopic and photopic, respectively) luminosity functions.

Green is considered one of the additive primary colors, along with red and blue. Additive combination of primary colors can produce most colors. In subtractive color mixtures, green is created by mixing yellow and blue pigments or dyes. On the HSV color wheel, the complement of green is magenta; that is, a color corresponding to an equal mixture of red and blue light (one of the purples). On a traditional color wheel, based on subtractive color, the complementary color to green is considered to be red.