color depth

The number of bits used to hold a screen pixel. Also called "pixel depth" and "bit depth," the color depth is the maximum number of colors that can be displayed. True Color (24-bit color) is required for photorealistic images and video, and modern graphics cards support this bit depth.

Per Pixel or Per Subpixel
The color depth of a screen can be referenced by the number of bits in each subpixel or by the total bits per pixel. For example, 8-bit color and 24-bit color often mean the same thing (see table below). The 8-bits refers to each red, green and blue subpixel, while 24-bit means all three. Likewise, 10-bit color subpixels and 30-bit color pixels are the same. See indexed color and bit depth.

Bitsper BitsSub per Total Common Pxl. Pxl. Colors Designation 1 2 (monochrome) 2 4 3 8 4 16 (VGA) 8 256 (Super VGA) 5-6** 16 65K (High Color) 8 24 16.7M (True Color) 8 32 16.7M (True Color + alpha) 10 30 1.1G (Deep Color) 12 36 64G (Deep Color) 16 48 256T (Deep Color) ** Red/Blue 5 bits; Green 6 bits

See color depth