Parameters

Color Lookup

IndexBits, the number of table entries and the corresponding table size are given below:

Normal machine

Here are grouped images of those full RGB palettes by 4 bits & 5 bits & 6 bits.

                4 bits = 12-bit RGB

Normal machine

                5 bits = 15-bit RGB

Normal machine

                6 bits = 18-bit RGB

Normal machine

Reference https://en.wikipedia.org/wiki/List_of_monochrome_and_RGB_color_formats#4-bit_grayscale_2