When studying a color we notice that its hue will vary depending on its illumination and its surroundings.
Illumination changes the hue due to the fact that color is in the light.
Color is the product of wavelengths that are either absorbed or reflected by the surface of an object. The hue appears to alter according to a colors surroundings as our retina is affected by these wavelengths and how the stimuli are communicated to the cortex, that part of the brain that enables us to distinguish one shade from another. Man has always been aware of the blue of the sky, the green of the grass, and the red of flowers or blood, but the cause of the color phenomenon was not known until the 19th century. In classical times, Greek scholars such as Plato, Aristotle and Pythagoras discoursed on the nature of color. They were created by blends of light and darkness.