Originally posted by: icebird0
8-bit = 16.7M colors
6-bit = 16.2M colors (actually much less, but uses dithering to produce that many)
More specifically, the 6-bit and 8-bit refers to each color. So 8-bit red, green, and blue = 24-bit color. 6-bit red, green, and blue = 18-bit color.
24-bit color = 16,777,216 "real" colors or 16.7M as commonly referred.
18-bit color = 262,144 "real" colors or 256K as commonly referred.
As you said, through dithering they increase that amount, but the colors aren't real anymore.