Light that falls on a surface can either be absorbed, transmitted or reflected, depending on the properties of the material involved. Reflection factors (r), absorption factors (a) and transmission factors (t) can be between 0 and 1 (0 -100%). The sum of the three factor is always 1. The transmitted or reflected radiation can be regular (1), scattered (2) or completely diffuse (3).

Transmission factor τ

The transmission factor is the ratio of transmitted light to incident light. Here are some typical transmission factors :


clear glass

90 ...92%

prismatic glass

70 ...90%

plastic (white, opaque)

40 ...60%