RGB

RGB refers to an additive color model made up of Red, Green, and Blue light.

In a 24-bit RGB color model made up of three 8-bit channels, there are 16,777,216 possible unique color values. On Macintosh operating systems, this is listed as "Millions of Colors". 16-bit RGB uses a similar layout called "thousands of colors", resulting in a color palette of 32×64×32 = 65,536 colors. Usually, there are 5 bits allocated for the red and blue color components (32 levels each) and 6 bits for the green component (64 levels), due to the greater sensitivity of the common human eye to this color. This doubles the 15-bit RGB palette.