brightness

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. This is a subjective attribute/property of an object being observed.

"Brightness" was formerly used as a synonym for the photometric term luminance and (incorrectly) for the radiometric term radiance. 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.^[1]

A given target luminance can elicit different perceptions of brightness in different contexts; see, for example, White's illusion and Wertheimer-Benary illusion.

In the RGB color space, brightness can be thought of as the arithmetic mean μ of the Red, Green, and Blue color coordinates^{[citation needed]} (although some of the three components make the light seem brighter than others, which, again, may be compensated by some display systems automatically):

Brightness is also a color coordinate in the HSB or HSV color space (hue, saturation, and brightness or value).

With regard to stars, brightness is quantified as apparent magnitude and absolute magnitude.

See also

• Luma (video)
• Luminance
• Luminance (relative)
• Saturation
• Apparent magnitude
• Absolute magnitude

Notes

External links

• Poynton's Color FAQ

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