‘Bit’ is a contraction of ‘binary digit’. In the binary system there are only two digits, 0 and 1, so that 2 in the denary (base 10) system is represented by 10, 3 by 11, 4 by 100, 5 by 101, and so on. In electronics, a bit can be represented by a switch that is either off (0) or on (1). Eight bits represent 28 (256) different numbers (a byte). A kilobyte (kb) is 1, 024 bytes, a megabyte (Mb) is 1, 024 kb, and a gigabyte (Gb) is 1, 024 Mb. The full file size of a digitally recorded scene is roughly three bytes per pixel, so that a 3-million pixel CCD array uses c.9 Mb of storage space, and a 10-million one c.30 Mb. However, this number can be greatly reduced by one of the various forms of compression.
— Graham Saxby
Bibliography
- Saxby, G., The Science of Imaging: An Introduction (2002)
