X4000

This indirect scheme restricts the number of available colors in an image CLUT—typically 256-cubed (8 bits in three color channels with values of 0–255)—although each color in the RGB24 CLUT table has only 8 bits representing 256 codes for each of the R, G, and B primaries, making 16,777,216 possible colors. However, the advantage is that an indexed-color image file can be significantly smaller than it would be with only 8 bits per pixel for each primary.