Colour theory

The first colour wheel was create by Sir Isaac Newton in 1666, it is a useful guide to colour mixing and being able to see the visual effects of certain colour combinations. Colour harmonies are when certain colour combinations are visually pleasing. 
The primary colours are red, yellow and blue, the idea is that by mixing these colours together you can create any other colour, these are called the secondary colours. The secondary colours are orange, green and purple and by mixing these you create the tertiary colours, by this theory the range of colours it is possible to create by mixing these are endless.
Colour context is how colours behave in relation to other colours and shapes. For example;
the red square stands out most on the black background and also looks larger than on the other backgrounds due to the high contrast.
 

 
Complimentary colours are those opposite to each other in the colour wheel, for example; red and green. These colour combinations create the maximum contrast and looks best when a warm colour is placed against a cool colour, e.g. red against green-blue.

Analogous colours are those next to each other on the colour wheel, they go well together and are visually pleasing to the eye. It is quite similar to the monochromatic theme.

Monochromatic colour schemes include all the shades and hues of one colour from lightest to darkest. I like this colour scheme as you can choose to go either very dark, bright and garish or subtle and muted. For example:

The achromatic colour scheme  is very similar to monochromatic, but it only involves white, greys and all the shades in between to black with no colour present.