contrast ratio

The ratio of the brightest white to the darkest black on a display screen. The larger the number, the darker the black is displayed. The two common methods for measuring contrast ratio are "full on/off contrast" and "ANSI contrast." Full on/off measures an all-white screen with an all-black screen and always produces a higher number than the ANSI approach.

Closer to a real world environment where light reflects back onto the screen, ANSI contrast uses a checkerboard of alternating black and white squares, and the average white output is divided by the average black output to yield the ratio. In order to impress prospective customers with the largest number possible, vendors may adjust their TVs to impractical user settings for the test. See contrast.