Definition: 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.

 Bits
 per   Bits
 Sub   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