The number of bits of colour information per pixel. A system using eight bits per pixel can display 256 (28) colors. A system using 16 bits per pixel can display 65,536 (216) colors. A system using 24 bits per pixel can display over 16.7 million colors. Twenty-four-bit colour is often called true colour because the human eye can distinguish among approximately six million different colors, or fewer than are available in a 24-bit colour system.