colorfrequency

Color frequency refers to the frequency of electromagnetic radiation that corresponds to a particular color, especially in the visible spectrum. In physics, color is tied to photon energy, which is proportional to frequency (E = hf) and, in vacuum, to wavelength via c = λf. Thus color can be described by either frequency or wavelength.

Visible light spans roughly 380 to 750 nanometers in wavelength, which corresponds to about 4.0 × 10^14 to 7.5 × 10^14 hertz in free space. When light enters a medium, its speed and wavelength change, but the photon frequency remains constant.

Perception of color is mediated by the eye and brain. Metamerism means different frequencies can look the same color when combined. Light of a single frequency produces a spectral color, while mixtures of frequencies create non-spectral colors in colorimetry.

Frequency is a central concept in spectroscopy and photonics. Detectors report spectral distributions as functions of frequency or wavelength, and E = hf underpins the quantum description of light and color.

The term color frequency is distinct from color temperature, which describes the perceived warmth of a light source and is defined in kelvin. In practice, physics uses frequency to discuss light, while colorimetry uses perceptual measures and color spaces.