What Are ANSI Lumens? An ANSI lumen in a particular unit of
measurement for the light output of a projector. A lumen (lm) is
a unit for measuring luminous flux, or the perceived output of a
light source. ANSI is an acronym for the American National
Standards Institute. As such, an ANSI lumen is a lumen measured
in the specific method defined by the American National
Standards Institute. In 1992, ANSI defined a method for
measuring the lumen output of projectors (both film and video).
The method involves adjustments of brightness and contrast,
measurements of a white field at nine designated spots on the
screen, and the averaging of the measurements multiplied by the
screen area. The ANSI method for measuring lumens is very
accurate and is therefore used in the marketing of projectors.
Manufacturers almost always list the ANSI lumen output of their
projectors as a point of comparison. The lumen is defined as 1
lm = 1 cd·sr = 1 lx·m2 ("cd" is candela, "sr" is steradian, "lx"
is lux and "m" is meter). In the mar