Lambert's cosine law
Lambert's law for a surface element whose radiance or luminance is the same in all directions of the hemisphere above the surface
Note 1 to entry: Lambert's cosine law can be expressed by
Note 2 to entry: This entry was numbered 845-04-56 in IEC 60050-845:1987.
Note 3 to entry: This entry was numbered 17-632 in CIE S 017:2011.