{{short description|Non-SI metric unit of luminance}} The '''lambert''' (symbol L<ref>{{Cite web |title=lambert |url=https://www.ies.org/definitions/lambert/ |access-date=2024-11-05 |publisher=Illuminating Engineering Society |language=en-US}}</ref><ref>{{Cite web |title=Luminance {{!}} Photometric Brightness {{!}} Nit {{!}} Stilb {{!}} Apostilb {{!}} Blondel {{!}} Lambert {{!}} Footlambert {{!}} Skot |url=https://www.schorsch.com/en/kbase/glossary/luminance.html |access-date=2024-11-05 |website=www.schorsch.com}}</ref>) is a non-SI metric unit of luminance named for Johann Heinrich Lambert (1728–1777), a Swiss mathematician, physicist and astronomer. A related unit of luminance, the foot-lambert, is used in the lighting, cinema and flight simulation industries. The SI unit is the candela per square metre (cd/m<sup>2</sup>).

== Definition == 1 lambert (L) = <math>\frac{1}{\pi}</math> candela per square centimetre (0.3183 cd/cm<sup>2</sup>) or <math>\frac{10^4}{\pi}</math> cd&nbsp;m<sup>−2</sup> {{luminance conversions}}

==See also== Other units of luminance: <!-- in order of relevance in regard to lambert --> * Apostilb&nbsp;(asb) * Blondel&nbsp;(blondel) * Bril&nbsp;(bril) * Nit&nbsp;(nit) * Stilb&nbsp;(sb) * Skot&nbsp;(sk)

{{SI light units}}

==References== {{reflist}} * [http://www.schorsch.com/kbase/glossary/luminance.html "Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase'']

Category:Units of luminance Category:Non-SI metric units