The lambert (symbol L
) is a non-
SI metric unit of
luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls wit ...
named for
Johann Heinrich Lambert
Johann Heinrich Lambert (; ; 26 or 28 August 1728 – 25 September 1777) was a polymath from the Republic of Mulhouse, at that time allied to the Switzerland, Swiss Confederacy, who made important contributions to the subjects of mathematics, phys ...
(1728–1777), a Swiss mathematician, physicist and astronomer. A related unit of luminance, the
foot-lambert
A foot-lambert or footlambert (fL, sometimes fl or ft-L) is a unit of luminance in United States customary units and some other unit systems. A foot-lambert equals 1/π or 0.3183 candela per square foot, or 3.426 candela per square meter (the corre ...
, is used in the lighting, cinema and flight simulation industries. The SI unit is the
candela per square metre
The candela per square metre (symbol: cd/m2) is the unit of luminance in the International System of Units (SI). The unit is based on the candela, the SI unit of luminous intensity, and the square metre, the SI unit of area.
The nit (symbol: ...
(cd/m
2).
Definition
1 lambert (L) =
candela
The candela (symbol: cd) is the unit of luminous intensity in the International System of Units (SI). It measures luminous power per unit solid angle emitted by a light source in a particular direction. Luminous intensity is analogous to radi ...
per
square centimetre
The square metre ( international spelling as used by the International Bureau of Weights and Measures) or square meter (American spelling) is the unit of area in the International System of Units (SI) with symbol m2. It is the area of a square w ...
(0.3183 cd/cm
2) or
cd m
−2
See also
Other units of luminance:
*
Apostilb
The apostilb is an obsolete unit of luminance. The SI unit of luminance is the candela per square metre (cd/m2). In 1942 Parry Moon proposed to rename the apostilb the blondel, after the French physicist André Blondel
André-Eugène Blondel (2 ...
(asb)
*
Blondel (blondel)
*
Bril
Bril is a surname. Notable people with the surname include:
* Ben Bril, Dutch boxer
*Joel Bril, pen name of Joel Löwe
* Matthaeus Bril, Flemish painter
*Paul Bril
Paul Bril (1554 – 7 October 1626) was a Southern Netherlands, Flemish painter ...
(bril)
*
Nit (nit)
*
Stilb (sb)
*
Skot (sk)
References
{{reflist
"Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase''
Units of luminance
Non-SI metric units