Gain (Projection Screen)

    Gain is the amount a reflective screen reflects the light that is hitting it. A matte white screen has a gain of 1. Higher levels of gain send back more light, while lower levels of gain send back less light. A high gain screen makes an image more visible in bright light conditions; however, high gain screens may alter the color of the image. Most projection screens have gains of 1 or slightly more.

Gamma

    Gamma is the relationship between an original scene as filmed (the video input) and the how the image is produced on a video display. A linear gamma results in the video input looking the same when it’s shown on the video display. Non-linear gamma results in changes to the scene as filmed, so it looks slightly different on the video display.

Gamma Correction

    Gamma correction accounts for the differences between the video input and the displayed image to create a more-identical reproduction of the original image. A non-linear gamma results in the video input not showing up exactly the same on the video display.

Geometry

    The geometry of a video display creates vertical lines that run parallel without bending or angling, and horizontal lines that run parallel without bending or angling. Proper picture geometry assures that an image does not vary in size across the screen and that it does not bend or warp.

Gray Scale

    A gray scale is the levels of gray ranging from true white to true black. The level of gray (or white or black) in a video signal is derived from the luminance portion of the signal.