This Demonstration is based on the Gamma Correction Demonstration by Michael Schreiber. This version adds brightness and contrast controls for the grayscale ramp. Many monitors and televisions have these controls, and this Demonstration shows how they impact a gray scale.
Setting the brightness (or black level) control too high shows clipping in the dark areas (grays are shown as pure black). Setting the brightness control too low makes the blacks appear as gray.
Setting the contrast (white level) control too high causes the bright areas to be clipped to pure white. Setting the contrast too low makes the whites appear gray.
Setting the per-color channel controls shows how individual colors can be clipped, thus tinting either end of the ramp.