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Complementary and tertiary colours

Complementary colours are colours that are opposite each other on the colour circle, such as orange and blue.

'Complement' means to make whole. Blue and orange (made by mixing red and yellow) contain all three primary colours (red, blue and yellow). When you mix any secondary colour (such as orange) with any opposite primary colour (such as blue), the resulting colours are called tertiary colours - they have all three primary colours in them.

Complementary colours react to each other in a similar way as black and white do.

  • When black is next to white the contrast enhances them, making white seem lighter and the black seem darker.
  • When you mix them together they neutralise each other to create grey.

Blue and orange, when placed next to each other, enhance each other. When mixed they neutralise each other and make a dark neutral colour between brown and black. It is the same for yellow with purple and red with green.

mixtures of blue and orange mixtures of yellow and purple mixtures of red and green four shades of grey
The top row of colours shows mixtures of blue and orange. The bottom row shows some of those colours with white. The top row of colours shows mixtures of yellow and purple and the bottom row those mixtures with white added. The top row of colours shows mixtures of red and green and the bottom row those mixtures with white. These greys were made by mixing all the left over paints on the palette after mixing the tertiary colours.


Find out for yourself how many different colours you can mix between orange and blue, red and green, and purple and yellow. Try adding touches of white to some of these colours.