Colorful Flower Photo

The trichromatic theory discussed above is strictly true when the visual system is in a fixed state of adaptation. In reality, the visual system is constantly adapting to changes in the environment and compares the various colors in a scene to reduce the effects of the illumination. If a scene is illuminated with one light, and then with another, as long as the difference between the light sources stays within a reasonable range, the colors in the scene appear relatively constant to us. This was studied by Edwin Land in the 1970s and led to his retinex theory of color constancy.
It should be noted, that both phenomena described above are readily explained and mathematical modeled with modern theories of chromatic adaptation and color appearance (e.g. CIECAM02, iCAM). There is no need to dismiss the trichromatic theory of vision, but rather it must be enhanced with an understanding of how the visual system adapts (adjusts) to changes in the viewing environment.
- Color naming
Colors vary in several different ways, including hue (shades of red, orange, yellow, green, blue, and violet), saturation, brightness, and gloss. Some color words are derived from the name of an object of that color, such as "orange" or "salmon", while others are abstract, like "red".