Luminous flux

Luminous-flux-Ulbrecht-SphereLuminous flux is the total quantity of light energy emitted per second by a light source.

It is designated by the symbol F and is expressed in lumens.

Luminous flux measurement of artificial light sources is carried out within a perfectly diffusing white sphere, called an Ulbricht sphere.

This equipment measures the total amount of lumens emitted by the tested light source by comparison with a calibrated lamp.