OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Basic Color Theory

In the physical world, light is composed of photons—in simplest terms, tiny particles traveling along a straight path¹ each with their own “color”, which in terms of physical quantities, is represented by their wavelength (or frequency).² Photons that we can see have wavelengths in the visible spectrum, which ranges from about 390 nanometers (the color violet) to 720 nanometers (the color red). The colors in between form the dominant colors of the rainbow: violet, indigo, blue, green, yellow, orange, and red.

1. Ignoring gravitational effects, of course.

2. A photon’s frequency and wavelength are related by the equation c = νλ, where c is the speed of light (3 × 10⁸meters/second), ν is the photon’s frequency, and λ its wavelength. ...