Literally single color, usually used to indicate black and white. There have been monochrome high line rate cameras and displays for many years. The EIA has standardized rates of up to 1225 scanning lines per frame. NHK developed a monochrome HDTV system with 2125 scanning lines per frame. Even higher number of scanning lines are used in conjunction with lower frame rates in cathode ray tube scanners used in printing and in film. These extremely high rates are possible because monochrome picture tubes have no triads.