The colour wheel

Primary Colours

The three hands on the colour wheel 'clock' indicate the three Primary colours. Red, Yellow, Blue.
In theory mixing two colours together, that two of the hands on the colour wheel point at, will give the second colour, i.e. in between the two hands. The Secondary colours as they are known. For more information about mixing these colours click the link.

Secondary Colours

These hands of the colour wheel 'clock' point to the secondary colours, as they are referred to Orange, Green, Violet. A list of suggested colours can be found by clicking the link.

If you mix a Primary colour with it's adjacent Secondary colour on the colour wheel this will give a Tertiary colour, classed as third in order.

Warm Colours
These are the warm colours of the spectrum from red through orange to yellow. You can use a small amount of a warm colour to warm the temperature of a cool colour and vice versa. The warm colours tend to come towards you, or feel closer to you, and come forward in a painting.
Use this knowledge in your work to advantage, for instance, cool blue colours to show distant land and a warm brown for land near to you.
Cool Colours

The cool colours of the colour wheel tend to go away from you, or feel distant to you, and recede in a painting. As with the warm colours, you can use a cool colour to change the temperature of a warm colour, just use it's opposite on the colour wheel.
You can use warm and cool colours side by side to contrast with each other

Complementary Colours

Complementary colours are opposite each other on the colour wheel, as shown by the hands on the colour wheel 'clock'. The same two colours that are opposite each other, when put side by side, contrast with each other. Complementary colours when mixed together produce a neutral or grey colour, sometimes with a leaning towards one colour. You can use a colours, complementary colour, to dull and darken the original colour instead of using black.