Brightness is an attribute of

visual perception Visual perception is the ability to interpret the surrounding Biophysical environment, environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the ...

in which a source appears to be radiating or reflecting

light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 te ...

. In other words, brightness is the

perception Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception involves signals that go through the nervous system ...

elicited by the luminance of a visual target. The perception is not linear to luminance, and relies on the context of the viewing environment (for example, see

White's illusion White's illusion is a brightness illusion where certain stripes of a black-and-white grating are partially replaced by a gray rectangle (see the figure). Both of the gray bars of A and B have the same color and opacity. The brightness of the gray ...

). Brightness is a subjective sensation of an object being observed and one of the color appearance parameters of many color appearance models, typically denoted as

Q

. Brightness refers to how much light ''appears to shine'' from something. This is a different perception than lightness, which is how light something appears ''compared to'' a similarly lit white object. The adjective ''

bright Bright may refer to: Common meanings *Bright, an adjective meaning giving off or reflecting illumination; see Brightness *Bright, an adjective meaning someone with intelligence People * Bright (surname) * Bright (given name) *Bright, the stage na ...

'' derives from an Old English '' beorht'' with the same meaning via metathesis giving Middle English ''briht''. The word is from a

Common Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the reconstructed proto-language of the Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from pre-Proto-Germanic into three Germanic br ...

', ultimately from a PIE root with a closely related meaning, *' "white, bright". "Brightness" was formerly used as a synonym for the photometric term '' luminance'' and (incorrectly) for the

radiometric Radiometry is a set of techniques for measuring electromagnetic radiation, including visible light. Radiometric techniques in optics characterize the distribution of the radiation's power in space, as opposed to photometric techniques, which ch ...

term ''

radiance In radiometry, radiance is the radiant flux emitted, reflected, transmitted or received by a given surface, per unit solid angle per unit projected area. Radiance is used to characterize diffuse emission and reflection of electromagnetic radiati ...

''. As defined by the US ''Federal Glossary of Telecommunication Terms'' ( FS-1037C), "brightness" should now be used only for non-quantitative references to physiological sensations and perceptions of light.�
Brightness
�� in Federal Standard 1037C, the ''Federal Glossary of Telecommunication Terms'' (1996) With regard to stars, brightness is quantified as

apparent magnitude Apparent magnitude () is a measure of the brightness of a star or other astronomical object observed from Earth. An object's apparent magnitude depends on its intrinsic luminosity, its distance from Earth, and any extinction of the object's ...

and

absolute magnitude Absolute magnitude () is a measure of the luminosity of a celestial object on an inverse logarithmic astronomical magnitude scale. An object's absolute magnitude is defined to be equal to the apparent magnitude that the object would have if it ...

. Brightness is an antonym of dimness or dullness.

New meaning

The United States Federal Trade Commission (FTC) has assigned an unconventional meaning to brightness when applied to lamps. When appearing on light bulb packages, brightness means luminous flux, while in other contexts it means luminance. Luminous flux is the total amount of light coming from a source, such as a lighting device. Luminance, the original meaning of brightness, is the amount of light per solid angle coming from an area, such as the sky. The table below shows the standard ways of indicating the amount of light.

Notes

External links

Poynton's Color FAQ
{{Authority control Vision Photometry hu:Világosság

New meaning

See also

Notes

External links