The smallest unit of illumination on a video display is called the picture element (pixel). Pixels are tiny dots which make up the whole image on a monitor. A character of text, for example, is made up of a block of pixels, some turned on, others off.
A pixel may be black or white, or it can be in color. The black and white monitors use pixels to generate a wide range of gray tones on the screen. In color monitors, pixels are usually arranged in groups of threes; red, green, and blue. By placing these three colors in close proximity, a variety of colors can be achieved. This is done by varying the intensity of the individual colors. This is similar to the artistic technique of pointillism, where the paint is applied in small dots, placing two colors (such as red and blue) next to each other, giving the impression of another color (in this case, purple).
