The brightness portion of the video signal, seen as gradations of black and white.

brightness, usually of a surface, i.e. luminous intensity per unit area. unit: candelas per square meter, usually expressed in millicandelas per square meter.

A unit of lighting measurement identical to radiance except that it is based on the visual (photopic) brightness of a light source rather than the total brightness. It is expressed in lumens (rather than watts) per steradian per surface unit. A commonly used alternative unit is the footlambert (fL). See Radiance below.

Portion of a television transmission that controls brightness of the red, green, and blue proportions in a television picture. The standard luminance setting in a picture is 30 percent red, 60 percent green, and 10 percent blue. These numbers can be adjusted to produce varying colors, grays, whites, and blacks.