Colour

On the computer screen there is a Red Green Blue (RGB) colour system. This means that all colours visible on screen are a combination of different intensities of red (255, 0, 0), green (0, 255, 0) or blue (0, 0, 255). Hue refers to the actual colour, for example the colour orange (255, 127, 0) has an orange hue. Saturation refers to the level of white (255, 255, 255) that a colour has; how pure the colour is, de-saturated colours appear pastel. Colours with a high saturation have a very intense hue. The tone of a colour can become darker by increasing the value of the colour closer to black (0, 0, 0).

Complementary Colour Scheme
Complementary colours are opposite each other on the colour wheel. The corresponding values (R+R, G+G or B+B) will equal 255.

Monochromatic Colour Scheme
Monochromatic colours have one hue with different saturation levels or tones. For example the three monochromes of the swatch colour (below) have the same hue value (92), but with different intensity (saturation or tone) closer to white or black.

Analogous Colour Scheme
Analogous colours have different hues that are close to each other on the colour wheel.

Triadic Colour Scheme
Triadic colours use three hues that are equally apart on the colour wheel.

Alternate Complement
Alternate compliment colours are made up of a triadic colour scheme with an additional complementary of one of the triadic colours.

Colour Scheme for Colour Blind People
Colour schemes for colour-blind people require contrast between the foreground (top of half of the colour wheel) and background (bottom half of the colour wheel) colours. Below is an example of a 'colour blind' safe colour scheme. It is made up of a triadic colour scheme for the foreground colours, and a complement of the 'blue' combined with a monochromatic colour scheme for the background colours.

Triadic

Monochromatic