visiblewavelength

Visible wavelength refers to the portion of the electromagnetic spectrum that can be detected by the human eye. In most adults, this range is commonly cited as roughly 380 to 750 nanometers, with some sources broadening to about 400 to 700 nm. Wavelengths shorter than the visible range lie in the ultraviolet, while longer wavelengths enter the near-infrared.

Color perception within the visible spectrum arises from photoreceptor cones in the retina and the brain’s interpretation of their signals. The spectrum includes familiar colors in approximate order: red, orange, yellow, green, blue, and violet. The eye’s sensitivity is not uniform; under bright daylight (photopic vision) it peaks near 555 nm (green), and sensitivity shifts under dim lighting (scotopic vision).

The boundaries of the visible range are not absolute and can vary among individuals and species. The interaction of visible light with the atmosphere also shapes everyday observations: shorter wavelengths are scattered more, giving the sky its blue color, while longer wavelengths dominate at sunrise and sunset. In scientific and technical contexts, visible light is measured and described using nanometers, and color perception is often analyzed with color spaces such as CIE or sRGB to relate wavelengths to perceived colors.

Applications of visible wavelengths span photography, imaging, displays, lighting, and optical sensors. The visible range is central to human vision-based technologies, color rendering and calibration, and considerations for glare and eye safety in lighting and laser use.