Colour mixing follows simple rules. The same methods apply to any type of paint, dye, coloured pencils, crayons or pastels. They even apply when layering coloured tissues, cellophane, glass, or similar solid medium. Colour theory is usually demonstrated with a colour wheel. Different shades of colour blend into one another around the wheel. All colours comes from just three primary colours: yellow, red and blue. Mixing these gives us the secondary colours: orange, green and purple which are positioned between the primary colours on the wheel. Tertiary colours are obtained by mixing any secondary colour with an adjacent primary colour.
Take some red and mix it with an equal amount of yellow on the palette. Stir together with the brush until it is a uniform orange. Wash out the brush between colours using water for water-based paint and mineral spirits for oil-based.
Place another blob of red on the palette. Wash out the brush and load it with blue. Mix blue and red together on the palette to obtain purple.
Repeat the process using blue and yellow paint. Mix together to form green.
Mix slightly larger volumes of the secondary colours using the above method. Add more red to some of the orange to make deeper orange. Experiment with adding more yellow to the remaining orange to make brighter, golden orange.
Using clean brushes, do the same with the green paint. Add more blue to some, and more yellow to a portion of the rest. See how many different shades of green you can make by subtle alterations to the balance of blue and yellow.
Repeat for purple. Add more blue to create indigo. Add more red to obtain brighter, redder purples.
Place blobs of the primary colours onto the palette. Experiment with adding white to these and to the secondary and tertiary shades mixed in the steps above. Make pastel versions of all the colours this way.
Create peach or apricot shades by adding white to oranges. Create lemon or primrose yellow by adding white to yellow. Mix pinks by adding white to red; lilacs by adding white to purple.
Create apple green by adding white to a mid-greens. Make soft lime by adding white to yellower greens.
Add white to blue to obtain shades of pale blue. Create turquoise by adding a hint of yellow to the light blue.
Brown, Grey and Darker Shades
Place some white on the palette, with a clean brush. Add a spot of black to make grey. Add gradually increasing amounts of black for darker greys. Reverse this if the grey becomes too dark, by adding more white.
Mix brown in several ways: mix all the primary colours together to obtain 'mud'; mix orange with green or try adding a touch of black to red. Experiment with browns – in nature brown comes in shades including rust and terracotta. Add more orange or red to brown to create these shades.
Add brown or black to darken any of the shades already mixed. Add only tiny amounts of black and beware of adding black to shades already containing white, as the result will be greyish.