true colour

(graphics)

true colour - A system where the red, green, and blue components of a colour are stored in display memory, as opposed to storing logical colours and using a colour palette to convert them to red, green, blue components. The advantage of true colour over a palette is that it does not restrict the range of colours which can be displayed on screen simultaneously. For example, if eight bits are used to store each component of each pixel then a total of 2^24 (about 17 million) different colours can be displayed at once which would require a (very expensive) palette with 3 * 2^24 bytes (about 50 megabytes) of memory. The disadvantage of true colour is that image transformations which would normally be done by changing the palette must be done to every pixel of the image which can be much slower. Compare high colour.