a) This voltage defines the picture’s black level. Video that dips below this level such as sync pulses are called blacker than black.

b) Strictly interpreted, denotes the light level at which a video signal representing picture black is reproduced on your TV screen. In terms of light output from a TV set, black areas of the picture should be represented by an absence of light. Something that is black or below black in the video signal shouldn’t produce any light from the display. c) Some TV sets actually use Black Level as a control name. It is a far better description of the function than the most commonly found name for it, Brightness.