Definition - What does Black Level mean?
Black level is the technical terminology used to describe the brightness of a TV. The black level of a TV helps to determine the level of picture quality. Generally, the darker the black level, the better the quality of the visuals. Different TV technologies such as cathode ray tube (CRT), liquid crystal display (LCD), light emitting diode (LED) and plasma manage their black levels differently, but advanced technologies such as LED have better black levels and are able to show visuals much better.
Techopedia explains Black Level
The deeper and truer the black levels, the better the quality of the visuals usually are. In fact, TVs that produce three-dimensional images are dependent on good black levels to produce depth. Plasma TVs tend to produce better quality black levels because the phosphors use less power to produce the darker scenes on the screen. However, LCD and LED TVs utilize more power to produce the required levels of black, because in order to produce true black colors they must adjust the individual crystals in the pixels to block light that would otherwise come through.