Projector brightness is measured in ANSI lumens. ANSI stands for "American National Standards Institute", who created a scale by which to measure the overall brightness value for projectors. The higher the ANSI lumens value the brighter and sharper the projected image will be.

less than 1, 000 --- Strictly for dark and light-controlled environments

1, 000 to 2, 000 --- Suitable for mildly lit entertainment and meeting rooms

More than 3, 000 --- Suitable for large venues such as auditoriums and churches.