The lambert (symbol L, la or Lb) 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 with ...

named for

Johann Heinrich Lambert Johann Heinrich Lambert (, ''Jean-Henri Lambert'' in French; 26 or 28 August 1728 – 25 September 1777) was a polymath from the Republic of Mulhouse, generally referred to as either Swiss or French, who made important contributions to the subj ...

(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: nt ...

(cd/m²).

Definition

1 lambert (L) =

\frac

candela The candela ( or ; 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 ...

per square centimetre (0.3183 cd/cm²) or

\frac

cd m⁻²

References

"Lighting Design Glossary: Luminance" at ''Schorsch Lighting Design Knowledgebase''
Units of luminance Non-SI metric units

Definition

See also

References