Bit stealing: how to get 1786 or more gray levels from an 8-bit color monitor

Abstract

The precision of human vision requires displays to be accurate to about 0.2% of the luminance range. We present a technique by which this grey-level precision can be achieved with the use of an 8-bit color monitor. The basic idea is to 'steal' adjacent bits from the color variation for use in increasing the precision of the luminance variation. On a monitor with 8 bits per color gun, the technique can provide 1786 or more grey levels at a cost of one bit of color jitter, with standard D/A hardware. The color variations are invisible under almost all conditions.