Unit of measure : candela per m² (cd/m²)

Luminance is the basic luminance perceived by the human eye. It is decisive for the impression of brightness of a luminous or illuminated surface.

Luminance L is defined by the luminous intensity Iε of an area A in the direction ε

A * cos ε is the "seen area" from direction ε

If diffuse reflection (Lambert radiators) is assumed for an illuminated surface, a simple relationship between luminance L and illuminance E of this surface results:

ρ = reflectance of the surface

The distribution of luminance between various surfaces in an illuminated interior is an important criterion for the quality of the visual experience. A balanced and harmonious distribution of brightness makes a room pleasant and visually interesting (cf. Brightness, Contrast, Uniformity).

Typical examples of luminance:



Sun depending on position of sun

600.000 ... 1.600.000.000

Dull incandescent lamp

20.000 ... 50.000

Compact fluorescent lamp

9.000 ... 25.000

Fluorescent lamp

4.000 ... 17.000

Office work goods

100 ... 200


20 ... 200

Office environment

10 ... 100