Color = Light.
Visible light, that is. All colors known to man can be found in the visible spectrum of light. On the longest wavelength/lowest frequency/lowest energy end we have RED, spanning across to the shortest wavelength/highest frequency/highest energy end with VIOLET (along with orange, yellow, green and blue in between). So, radio waves (plus infrared and microwave) have the least energy, and gamma rays (plus UV and X-rays) have the most energy, which is part of what makes them so dangerous to humans. The whole range of frequencies and energies is called the electromagnetic spectrum.
Visible light occupies only one-thousandth of a percent of this spectrum.
Humankind’s attempts to recreate color in the natural world date back as far as our oldest civilizations, the early Paleolithic period, aprox 350,000 BC – where the first pigments, or pure color in powdered form, were suspended in a medium to make paint.
“The world in which we live is teeming with color: the sky, earth, water, and fire all have distinct colors. From time immemorial, we who delight in such perceptions have tried to reproduce these colors in our day-to-day surroundings. What could be more normal? For color is the child of light, the source of all life on earth. The challenge in finding materials capable of producing lasting colors in the world around us has preoccupied humankind from prehistory to the present day. ” quote from Colors: The Story of Dyes and Pigments by Francois Delamare & Bernard Guineau