What is a lumen?

A lumen (lm) is a standard unit to measure the total amount of light emitted by a source such as an LED. As this a measurement of the light source itself within a product, similar devices with the same listed lumens can appear a different brightness due to the efficiency of the design.

In regards to our digital art projectors, the lumen measurement provides a reference to the difference in brightness between the models. Because the lumen output is the total amount of light emitted and is fixed, as the size of the projected image increases the image will appear dimmer as the light is spread out over a larger area.