Or greyscale. A range of accurately known shades of grey printed out for use in calibrating those shades on a display or printer. In graphics, composed of discrete shades of gray. For displays, a colour format in which each pixel is determined by an 8-bit value. This value maps to RGB space with the red, green, and blue components all taking on the 8-bit value. The result is pixels which can range from black, to gray, to pure white.