Bitmapped graphics screens are divided into tiny regions called pixels. On black and white monitors, each pixel is either illuminated (white) or not illuminated (black). More sophisticated monochrome monitors provide a range of varying intensities for illuminating each pixel. So, instead of just black and white, there are shades of grey. The term grey-scale applies this kind of monitor. Colour monitors use a combination of the three primary colours, with varying intensities, to illuminate each pixel.