Lambert (unit)

The lambert (symbol L, la or Lb) 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/m2).

Definition
1 lambert (L) = $$\frac{1}{\pi}$$ candela per square centimetre (0.3183 cd/cm2) or $$\frac{10^4}{\pi}$$ cd m−2