Color vision and the visible spectrum

Physically speaking, light is radiation in the form of electromagnetic waves, and can therefore be quantified by certain characteristics such as wavelength and amplitude. Color theory studies how such characteristics get translated into a sensory perception, of color.

The human eye supports two types of vision: photoptic vision occurs under bright light, and scotopic vision occurs under dim light. These two modes come from using different types of vision cells, namely cones and rods respectively. Only cones sense color, and are sensitive to light with wavelengths in the range of 350-800 nm. The actual range can vary from person to person.