Number of bits to represent three colors?

Question

Can somebody explain why are 24 bits needed to represent RGB colour? Isn't RGB just 3 colours? Hence, 2^2=4 colors.

That is, we only need 2 bits!

Answer 1

RGB (red, green, blue) are the primary colors of light that when mixed together form every other color (24 bits = total possible 16,777,216 combinations).

The 24 bits are split into 3, 8-bit chunks and are used to describe how much of each RGB color should be used.  Mixing them yields almost every color you could want to use .  Some examples -

Red    11111111 (255)

Green 00000000 (0)

Blue   00000000 (0)

Gives you RED

Red    00000000 (0)

Green 11111111 (255)

Blue   00000000 (0)

Gives you GREEN

Red    00000000 (0)

Green 00000000 (0)

Blue   11111111 (255)

Gives you BLUE

Red    11111111 (255)

Blue   00000000 (0)

Green 11111111 (0)

Gives you YELLOW

Red    11111111 (255)

Green 01111111 (127)

Blue   00000000 (0)

Gives you ORANGE

Red    00000000 (0)

Green 00000000 (0)

Blue   00000000 (0)

Gives you BLACK

Red    11111111 (255)

Green 11111111 (255)

Blue   11111111 (255)

Gives you WHITE

Check out the links for more explanation and examples of colors and their RGB values.

NOTE - Red, YELLOW, Blue are the primary colors of ink/paint that are used to make all colors.