Early computer monitors had "single bit" color depth—the pixel was either on or off. Color monitors allowed more vibrant displays, but color depth was still limited. 8-bit displays (which were similar to Indexed color mode), allowed up to 256 colors to be chosen from a wider range. 16-bit displays advanced this further, using 5-bit (32 levels) Red and Blue channels, and a 6-bit (64-levels) Green channel.