Binary characters digits, "ones" and "zeros", are normally assembled into small standard-length groups just large enough to communicate a useful number. Such groups, normally consisting of eight bits, are known as bytes. One eight-bit byte can be used to represent an number in the range 0 - 255. The gaps in the binary numbers in the table below have been inserted purely to enhance readability.

In colour systems, such as the RGB colour model, primary colours are mixed in precisely-controlled proportions to achieve the large number of colours required to create an image. In the RGB system, the red, blue and green components are each allocated one eight-bit byte. This determines the mixture of primary colours required for each of the possible 16.7 million possible colour combinations. Each output of each sensor element, or pixel, therefore delivers three eight-bit bytes of information. This system, known as 24-bit colour, is illustrated in the example below which shows the data for a single orange pixel.