Colour depth
Number of bits representing each pixel colour. Colour depth determines colour palette size and image quality. Common depths: 8-bit (256 colours), 24-bit (16M colours), 32-bit (with alpha).
Formula
Number of colours = 2^(colour depth)
Real World
Early Nintendo Game Boy games used 2-bit colour depth (4 shades of green), while modern Instagram photos use 24-bit true colour to display over 16 million colours on your phone screen.
Exam Focus
For image file size, use: width × height × colour depth. Remember to convert bits to bytes by dividing by 8.
How well did you know this?