Visible spectrum

Visible Spectrum is a portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 380 to 750 nanometers. In terms of frequency, this corresponds to a band in the vicinity of 430–790 THz.

Overview

The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Unsaturated colors such as pink, or purple variations such as lavender, are not present, because they can be made only by a mix of multiple wavelengths. Colors containing only one wavelength are also called pure colors or spectral colors.

Physical properties

Visible wavelengths pass through the "atmosphere" to a degree that does not strongly depend on wavelength. The human eye's response is defined by subjective testing, but the atmospheric windows are defined by physical measurement. The "atmosphere" transmission windows coincide with the visible response of the human eye.

Perception of color

The perception of color derived from the spectrum of light wavelength is called colorimetry. Different methods are used to define the "color space" for the perception of color, such as the CIE 1931 and 1964 color spaces. These spaces define a three-dimensional color volume, with the visible spectrum located at the outer rim of the volume.

See also

• Color vision
• Color theory
• Colorimetry
• Electromagnetic spectrum
• Light

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