<hardware, graphics> (bpp) The number of bits of information
stored per pixel of an image or displayed by a graphics
adapter. The more bits there are, the more colours can be
represented, but the more memory is required to store or
display the image.
A colour can be described by the intensities of red, green and
blue (RGB) components. Allowing 8 bits (1 byte) per
component (24 bits per pixel) gives 256 levels for each
component and over 16 million different colours - more than
the human eye can distinguish. Microsoft Windows [and
others?] calls this truecolour. An image of 1024x768 with
24 bpp requires over 2 MB of memory.
"High colour" uses 16 bpp (or 15 bpp), 5 bits for blue, 5 bits
for red and 6 bits for green. This reduced colour precision
gives a slight loss of image quality at a 1/3 saving on
memory.
Standard VGA uses a palette of 16 colours (4 bpp), each
colour in the palette is 24 bit. Standard SVGA uses a
palette of 256 colours (8 bpp).
Some graphics hardware and software support 32-bit colour
depths, including an 8-bit "alpha channel" for transparency
effects.
(1999-08-01)
Nearby terms:
bit rot « bit slice « bits per inch « bits per pixel » bits per second » bit string » bit stuffing
