The level of brightness at the darkest (black) part of a visual image or the level of brightness at which no light is emitted from a screen resulting in pure black. Black level varies from video display to video display with better displays having a better black level. A poor video display may have a black level in which the “black” is actually a dark charcoal gray color. When a video display cannot achieve a true black level, the screen will lose some saturation in colors and will appear slightly washed out. Additionally, black images will not appear black but gray. This could be annoying particularly if you watch letterboxed movies with black bars above and below the image. A video display with a poor black level will display the bars not as true black as intended but as dark gray. RT projectors and direct view televisions tend to have the best black levels while LCD projectors as a general rule suffer from black level problems. Of course, any format of video display will have out-performers and poor performers so it is possible to find a LCD projector with a good black level (although it probably will not achieve a true black).