HTML Colours are defined using a hexadecimal notation (Hex) for the combination of Red, Green, and Blue colour values (RGB). The lowest value that can be given to one of the light sources is 0 (in Hex: 00). The highest value is 255 (in Hex: FF).

Hex values are specified as 3 pairs of two-digit numbers, starting with a # sign. The lowest value that can be given to one of the light sources is 0 (Hex: 00), the highest value is 255 (Hex: FF).