Colour is what the eyes see when light is reflected off an object.

Colour has three properties:

Hue. Hue is the name of a colour, such as red, blue, or yellow.
Value. Value is the lightness or darkness of a hue (colour). The value of a hue can be changed by adding black or white.
Intensity. Intensity is the brightness or dullness of a hue (colour). Pure hues are high-intensity colours. Dull hues are low-intensity colours.

 

A colour wheel is the spectrum bent into a circle. It is a useful tool for organizing colours.

The colour wheel shows primary, secondary, complementary and intermediate colours.

There are three primary colours; red, blue, and yellow. Primary colours are hues which can be mixed to create all other colours.

There are three secondary colours; green, orange, and violet. Secondary colours are the hues between the primary hues on the colour wheel. the secondary hues are create by mixing two primary hues. To get orange, you mix equal parts of red and yellow. To get Violet, you mix equal parts of red and blue. To get green, you mix equal parts of blue and yellow.

 

Complimentary colours. Complimentary colours are colours that are across from each other on the colour wheel. Violet and yellow are complimentary, Blue and orange are complimentary, and red and green are complimentary.

Intermediate colours. There are six intermediate colours, red-orange, red-violet, blue-violet , blue-green, yellow-green, yellow-orange. These colours are created by mixing a secondary colour with a primary colour.

Warm colours. Warm colours express warmth; they are red, yellow and orange.

Cool colours. Cool colours have the feel of being cold or cool; they are blue, violet and green.