Primary Colours

There are three primary colours: Red, Blue, and Yellow. They are called primary colours because they cannot be created by mixing other colours. Primary colours form the basis for colour theory or colour mixing, as by using these three colours it's possible to mix most other colours.
A primary colour can be any of the Red, Blue, or Yellow pigments available to an artist. Each combination will give you a different result, and that's part of what makes colour mixing so interesting.
A primary colour can be any of the Red, Blue, or Yellow pigments available to an artist. Each combination will give you a different result, and that's part of what makes colour mixing so interesting.
Secondary Colours

A secondary colour is a colour made by mixing two primary colours together: Yellow and Red to get Orange, Yellow and Blue to get Green, or Red and Blue to get Violet (Purple). The secondary colour depends on how much of each primary colour is used.
For example, if more Red is added than Yellow, you get a reddish Orange, and if more Yellow than Red is added, you get a yellowish Orange.
For example, if more Red is added than Yellow, you get a reddish Orange, and if more Yellow than Red is added, you get a yellowish Orange.
Tertiary Colours

These colours are created when mixing one secondary and one primary colour together.
For example, Blue and Violet (Purple) make Blue-Violet
Three or more separate colours are mixed (one primary and one secondary – (the combination of two primaries), and in this colour wheel each tertiary colour being created will be an equal combination of the two colours, left and right, surrounding an open segment.
The tertiary colours are: Yellow-Orange, Red-Orange, Red-Violet, Blue Violet, Blue-Green, and Yellow-Green.
For example, Blue and Violet (Purple) make Blue-Violet
Three or more separate colours are mixed (one primary and one secondary – (the combination of two primaries), and in this colour wheel each tertiary colour being created will be an equal combination of the two colours, left and right, surrounding an open segment.
The tertiary colours are: Yellow-Orange, Red-Orange, Red-Violet, Blue Violet, Blue-Green, and Yellow-Green.
Here are examples of how Primary and Secondary colours can been used in paintings.