Luminance

Luminance is the amount of light energy emitted or reflected from an object in a specific direction. Luminance is the only form of light we can see.

 

Luminance is measured in candela per square metre (cd/m2) or nit (these two terms being interchangeable).

Light energy reflected from an object

                                     Fig 6

1 nit is defined as the luminance of a purely white object