3-bit color
From The Glossary of Digital Photography
A color system in which each pixel is represented by 3 bits, which means that each pixel can be eight (23) possible colors. There is 1 bit for each of the three colors: red, green, and blue; therefore each color can be 0 (off) or 1 (on). This approach leads to the colors: black (0,0,0), blue (0,0,1), green (0,1,0), cyan (0,1,1), red (1,0,0), purple (1,0,1), yellow (1,1,0), and white (1,1,1). The system that was used by the early Radio Shack TRS-80 computer, it is not commonly used today.
