ABSTRACT
Zero on the scale, or absolute black, represents the blanking level, which can be seen as the black bar that rolls on a monitor screen when the vertical hold is out of adjustment. Reference black, the darkest possible value within the picture, should be set at 7.5 IRE units; this is called the setup level or pedestal. This represents the darkest value a picture can have, but this does not mean every picture must contain picture elements of this value. Any signal that exceeds 100 IRE will appear as white in the picture. The portion of the video signal that normally measures -40 IRE is the sync pulse, which regulates the scanning and field rate, and the portion in the -20 to +20 IRE range outside the picture is the color burst, which carries the chrominance (color) information.
