Lumens

Also known as “luminous flux,” lumens are a measurement of light used to compare the total amount of visible light that is output from a light emitting source. Lumens differ from radiant flux in that radiant flux includes all electromagnetic waves emitted, while lumens are weighted according to a model of the human eye’s sensitivity to visible wavelengths. Lumens are measured using a highly specialized light integrating sphere. Lumens are related to lux in that one lux is one lumen per square meter.