Red, green, blue, abbreviated to RGB, is a computer colour coding system which is the closest to the hardware. Computer screens recreate a colour by additive synthesis from three primary colours, red, green and blue, forming a mosaic on the screen that is too small to be seen. RGB coding indicates a value for each of these primary colours.

The RGB colour mode is designed to reproduce the colour on screens and is therefore not suitable for correctly viewing the colours of a print.