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 or reflected from a particular area, and falls within a given
solid angle. The
SI unit for luminance is
candela per square metre (cd/m
2). A non-SI term for the same unit is the "nit". The
CGS unit of luminance is the
stilb, which is equal to one candela per square centimetre or 10 kcd/m
2.