Color discrimination is the ability to distinguish between different colors. It is a fundamental aspect of color perception.

Deuteranopia is a type of color blindness in which the cones in the retina that are responsible for detecting green light are either missing or malfunctioning. This results in the inability to distinguish between red and green.

Simultaneous contrast is the phenomenon in which the perception of color is influenced by the surrounding colors. For example, a white object may appear to be slightly bluish when placed on a red background.

The trichromatic theory proposes that the perception of color is determined by the activity of three types of cone cells in the retina: short-wavelength-sensitive (S), medium-wavelength-sensitive (M), and long-wavelength-sensitive (L).

Color adaptation is the phenomenon in which the perception of color changes over time in response to changes in the surrounding light conditions.

The opponent-process theory proposes that the perception of color is determined by the opponent processing of signals from the cone cells in the retina. This theory suggests that the visual system processes color information in terms of opposing pairs of colors, such as red-green, blue-yellow, and black-white.

Color symbolism is the phenomenon in which the perception of color is influenced by the cultural and linguistic context. Different cultures and languages may associate different meanings and symbols with different colors.

The tetrachromatic theory proposes that the perception of color is determined by the activity of four types of cone cells in the retina: short-wavelength-sensitive (S), medium-wavelength-sensitive (M), long-wavelength-sensitive (L), and ultraviolet-sensitive (UV).

Color expectation is the phenomenon in which the perception of color is influenced by the expectations and beliefs of the observer. For example, a person who expects to see a red object may be more likely to perceive an object as red, even if it is actually a different color.

The dichromatic theory proposes that the perception of color is determined by the activity of two types of cone cells in the retina: short-wavelength-sensitive (S) and long-wavelength-sensitive (L).

Color assimilation is the phenomenon in which the perception of color is influenced by the spatial arrangement of colors. For example, a small patch of color may appear to be a different color when it is surrounded by a different color.

The monochromatic theory proposes that the perception of color is determined by the activity of one type of cone cell in the retina. This theory is no longer widely accepted.

Color size effect is the phenomenon in which the perception of color is influenced by the size of the colored object. For example, a small patch of color may appear to be a different color than a larger patch of the same color.

The pentachromatic theory proposes that the perception of color is determined by the activity of five types of cone cells in the retina: short-wavelength-sensitive (S), medium-wavelength-sensitive (M), long-wavelength-sensitive (L), ultraviolet-sensitive (UV), and violet-sensitive (V).

Color shape effect is the phenomenon in which the perception of color is influenced by the shape of the colored object. For example, a red object may appear to be a different color when it is presented in a different shape.