Color Perception

The human eye is capable of detecting a portion of the electromagnetic spectrum called the visible light spectrum, which encompasses wavelengths ranging from about 380 to 750 nanometers. This varies from person to person, and other animals perceive different bands of this spectrum, which in some cases allows them to see or otherwise detect infrared and ultraviolet radiation, in addition to the colors most humans can detect.

Each color we perceive is either a distinct wavelength of electromagnetism, its gradients contained within a portion of that larger spectrum of wavelengths, or a combination of multiple single-wavelength colors. The colors we perceive from a single wavelength, like violet and red, are called pure colors, while those we perceive as a result of multiple combined wavelengths, like magenta, are called unsaturated colors.

Our visual system is activated by the photoreceptors in our eyes, which are stimulated by electromagnetic radiation in the right range. When they’re stimulated, they knock neurons around so that our brains can process the color of things in our physical environments.