Definitions for "Colour depth"
Keywords:  depth, pixel, grey, true, bit
Number of bits associated to each pixel to define the colour. The number of colours available is based on the 2bit per pixel formula. With 24 bits per pixel (that is 16,777,216 colours) you have a true colour, that is a real colour.
Amount of data used to create colour on a monitor display.
This refers to the maximum number of colours that can be recorded by digital cameras and scanners or that can be displayed by graphics cards. A true colour representation can be achieved at a colour depth of 8 bits per primary colour, that is a 24 bit colour depth. In this case, 256 bits are available for one pixel. With an RGB signal, this value is then multiplied by a factor of three so that a total of 256 x 256 x 256 = 16,777,216 colours can be displayed. High-end scanners, graphic cards etc. provide a minimum colour depth of 24 bit.