It is estimated that humans receive 70% to 80% of their sensory information through sight. This means they also make about the same percentage of their decisions based on what they see. A big component of this visual perception is color, and the color humans see is based on the color characteristics of the light being used. Although people perceive various light sources as “white light,” in fact, depending on the source, the light can be biased quite heavily toward the red/yellow, blue or green portions of the visual spectrum. These various sources will substantially shift color perception.
Although the human visual system has a broad range of color shades that can be perceived (the average observer can see over two million colors, while a trained observer can see over four million), the visual system also adapts to the lighting environment. It scans the scene and picks the lightest color, perceiving it as “white,” and all the other colors fall into place as necessary. Through the course of human existence, this has allowed people to identify a ripe red apple in the warm yellow-red glow of early morning and still see that same apple as red and ripe in the middle of the day, when the light is bluest. For survival, the human system adapts.