Difference between revisions of "Illuminance"

2-1-055

Illuminance (at a point of a surface)

The quotient of the luminous flux (dF) incident on an infinitesimal element of the surface containing the point under consideration, by the area (dA) of that element.

Symbol: E

Unit: lux (lx)

lumen per square metre (lm/m2)

Reference: C.I.E. (modified)

Note 1: If the luminous flux may be considered uniformly distributed over a finite plane surface of area A, the illuminance on this surface is given by

(Equation)

where F is the total luminous flux incident on the surface.

Note 2: The continued use of the former term Illumination with the meaning above is now deprecated as this use conflicts with the general meaning of the term (2-5-010).

Please note that this is the term as it stands in the original IALA Dictionary edition (1970-1989)

English