Comment text appears below:
The following paragraph from the review is not technically correct. Gain. The most obvious difference between the 0.8-gain screen and the 1.4-gain screen is, of course, gain. Gain is a measurement of the light reflected from a screen at a zero degree viewing angle. If you took a theoretical 100-lumen flashlight and pointed it at a perfect 1.0 gain screen from directly in front, the light reflected back at you would measure 100 lumens, while a 0.8 gain screen would reflect 80 lumens, and a 1.3 gain screen would measure 130 lumens. No screen can create light by reflecting back more lumens than from the source. What a screen can do is to direct reflected light from the source over a narrower viewing angle which creates the gain. This increases the ratio of foot lamberts reflecting off the screen to foot candles projected onto the screeen. Foot candles is equal to lumens per square foot. Foot lamberts is a measurement of brightness of reflected light from a surface and is equal to foot candles onto a surface with unity gain.

Stephen Hulsey