Editing Brightness

{{Short description|Perception of light level}}
{{Other uses}}
[[File:LightningVolt Deep Blue Sea.jpg|thumb|Decreasing brightness with depth (underwater photo as example)]]

'''Brightness''' is an attribute of [[visual perception]] in which a source appears to be radiating/reflecting [[light]].<ref>"[http://www.merriam-webster.com/dictionary/bright Bright Definition & Meaning]", Merriam-Webster Dictionary.</ref> In other words, brightness is the [[perception]] dictated 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]]).

Brightness is a subjective sensation of an object being observed and one of the [[Color appearance model#Color appearance parameters|color appearance parameters]] of many [[color appearance model]]s, typically denoted as <math>Q</math>. 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.<ref>Robert William Gainer Hunt: ''Some comments on using the CIECAM97s colour-appearance model''</ref>

The adjective  ''[[:wikt:bright|bright]]'' derives from an Old English ''[[beorht]]'' with the same meaning via metathesis giving Middle English ''briht''. The word is from a [[Proto-Germanic]] ''{{lang|gem-x-proto|berhtaz}}'', ultimately from a [[Proto-Indo-European language|PIE]] root with a closely related meaning, *''{{PIE|bhereg-}}'' "white, bright".
"Brightness" was formerly used as a synonym for the [[photometry (optics)|photometric]] term ''[[luminance]]'' and (incorrectly) for the [[radiometric]] term ''[[radiance]]''. As defined by the US ''Federal Glossary of Telecommunication Terms'' ([[Federal Standard 1037C|FS-1037C]]), "brightness" should now be used only for non-quantitative references to physiological sensations and perceptions of light.<ref>“[http://www.its.bldrdoc.gov/fs-1037/dir-005/_0719.htm Brightness]” in Federal Standard 1037C, the ''Federal Glossary of Telecommunication Terms'' (1996)</ref>
Brightness is an antonym of "[[:wikt:dimness|dimness]]" or "[[:wikt:dullness|dullness]]".

With regard to [[star]]s, brightness is quantified as [[apparent magnitude]] and [[absolute magnitude]].

Two [[Solar symbol|pictograms resembling the Sun]] with rays are used to represent the settings of [[luminance]] in [[Electronic visual display|display devices]]. They have been encoded in [[Unicode]] since version&nbsp;6.0 (October 2010) in the Miscellaneous Symbols and Pictographs block under U+1505 as "low brightness symbol" (🔅) and U+1F506 as "high brightness symbol" (🔆).<ref>{{cite web |url=https://unicode.org/charts/PDF/U1F300.pdf |title=Miscellaneous Symbols and Pictographs |publisher=Unicode Consortium |year=2023}}</ref>

The United States [[Federal Trade Commission]] (FTC) has assigned an unconventional meaning to brightness when applied to [[Electric light|lamps]].  When appearing on light bulb packages, brightness means [[luminous flux]], while in other contexts it means luminance.<ref name="ftc">{{cite web |title=Shopping for Light Bulbs |publisher=United States [[Federal Trade Commission]] |url=https://www.consumer.ftc.gov/articles/0164-shopping-light-bulbs |access-date=March 13, 2017}}</ref>  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.

{{SI light units}}

==See also==
* [[Luma (video)]]
* [[Luminance (relative)]]
* [[Luminosity]]

==References==
{{Reflist}}

==External links==
{{Commons category-inline|Brightness|lcfirst=yes}}
{{wiktionary|brightness}}
* [http://www.poynton.com/ColorFAQ.html Poynton's Color FAQ]

{{Authority control}}

[[Category:Vision]]
[[Category:Photometry]]

[[hu:Világosság]]