Color is light energy
When white light is passed through a prism it is separated into eight distinct light rays. These rays are called the 'Colors of the Spectrum'. They are the same colors that can be seen when the suns' light is pasted through rain drops. The resulting phenomenon is what most of us have experienced as a rainbow.
The only energy that keeps man alive, is light (color) energy. Every other form of energy rays are damaging to the human organism. The physiology of color is the process that takes place during visual perception. And the psychology of color includes the sensation our brains make out of our perceptions.