Absorptance quantifies the fraction of light or thermal radiation that a material takes in rather than reflecting or transmitting. It is a dimensionless number between 0 and 1. Lighting designers and thermal engineers use this metric to calculate heat buildup in luminaires and to determine the efficiency of optical baffles.
Heard on the job
The black anodized housing has an absorptance of 0.95, which helps it pull heat away from the LED array.
Insider tip
Do not confuse absorptance, which is a measurable property of an object, with absorbance, which is an optical density measurement used in chemistry.
Also heard as
- absorption factor