ANSI Lumen (On screen brightness)

To measure ANSI lumen on projectors the screen is divided into 4 x 4 rectangles, specified by American national standards industry (ANSI).

The method for measuring ANSI lumens are quite simple, but the projector obviously need to be set up according to ANSI standards, which are:

1. The projector is set up to display an image in a room at a temperature of 25 degrees Celsius.
2. The brightness and contrast of the projector is then adjusted according to ANSI standard document IT7.215
3. The light output is then measured on a full white field at nine specific locations around the screen and averaged out. This average is then multiplied by the screen area to give the brightness of the projector in "ANSI lumens”.

In order to compare brightness of various projectors accurately, all projectors must be measured according to the same standard. 

The ANSI standard has been adopted by most reputable projector manufacturers, and will be stated as such on all documentation.