The original Amiga had 4 bits each for hue (H), saturation (S), and luminance (L)--a color representation that mapped elegantly to the NTSC video signal. To make the best use of this representation, Miner developed a special hold-and-modify mode, in which data would tell the video output chip how to alter the H, S, or L values from the previous pixel on the screen; it could display subtly shaded images with remarkable realism.
That's news to me. I thought it was always RGB...
