Brightness is an attribute of visual perception in which a source appears to emit a given amount of light. In other words, brightness is the perception elicited by the luminance of a visual target. Visual perception is one of the senses, consisting of the ability to detect light and interpret (see) it as the perception known as sight or naked eye vision. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye (visible light) or, in a technical or scientific context, electromagnetic radiation of any wavelength. ... Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ...

"Brightness" was formerly used as a synonym for the photometric term luminance and (incorrectly) for the radiometric term radiance. According to Federal Standard 1037C, "brightness" should now be used only for nonquantitative references to physiological sensations and perceptions of light. Photometry is a term used in physics, optics, and illuminating engineering for the measurement of quantities associated with light. ... Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ... In telecommunication and physics, radiometry is the science of radiation measurement. ... Radiance is a physical quantity used in the sphere of radiometry to measure the intensity of a light beam, defined as power per unit solid angle per unit projected area of the source. ... Federal Standard 1037C entitled Telecommunications: Glossary of Telecommunication Terms is a U.S. Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended. ...

Note, that the same target luminance can elicit different perceptions of brightness in different contexts. (See, e.g. White's illusion and Wertheimer-Benary illusion) Whites illusion is an optical illusion illustrating the fact that the same target luminance can elicit different perceptions of brightness in different contexts. ...

In the RGB color space, brightness can be thought of as the arithmetic mean μ of the Red, Green, and Blue color coordinates (although some of the three components make the light seem brighter than others, which, again, may be compensated by some display systems automatically): An RGB color space is any additive color space based on the RGB color model. ... In mathematics and statistics, the arithmetic mean of a set of numbers is the sum of all the members of the set divided by the number of items in the set (cardinality). ...

Brightness is also a color coordinate in HSB color space. The hue saturation value (HSV) model defines a color space in terms of three constituent components: HSV color space as a color wheel Hue, the color type (such as red, blue, or yellow): Ranges from 0-360 (but normalized to 0-100% in some applications) Saturation, the vibrancy of the...

With regard to stars etc. see apparent magnitude, absolute magnitude. STAR is an acronym for: Scientific and Technological Advanced Research Labs, a fictional research organization in the DC Comics universe. ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... In astronomy, absolute magnitude is the apparent magnitude, m, an object would have if it were at a standard luminosity distance away from us. ...

See also

• Luminance
• Saturation

Luminance (also called luminosity) is a photometric measure of the density of luminous intensity in a given direction. ... Scale of saturation (0% at bottom). ...

Helping links

• Correction of Brightness with Gimp

References

• Poynton's Color FAQ