Brightness is an attribute of visual perception in which a source appears to be radiating or reflecting light.^[1] 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.

Contents 1 Terminology 2 Brightness of sounds 3 See also 4 Notes 5 External links

[edit] Terminology

"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.^[2]

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 (although some of the three components make the light seem brighter than others, which, again, may be compensated by some display systems automatically):^[3]

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

[edit] Brightness of sounds

The term "brightness" is also used in discussions of sound timbres, in a rough analogy with visual brightness. Timbre researchers consider brightness to be one of the perceptually strongest distinctions between sounds^[4], and formalize it acoustically as an indication of the amount of high-frequency content in a sound, using a measure such as the spectral centroid.

[edit] See also

• Luma (video)
• Luminance (relative)
• Luminosity

[edit] Notes

[edit] External links

Look up brightness in Wiktionary, the free dictionary.

• Poynton's Color FAQ