Complementary colours are pairs of colours that contrast with each other more than any other colour, and when placed side-by-side make each other look brighter

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  • Claude Monet, 'Woman Seated on a Bench' circa 1874
    Claude Monet
    Woman Seated on a Bench circa 1874
    Oil on canvas
    frame: 900 x 720 x 85 mm
    support: 737 x 559 mm
    Presented by the Art Fund 1926
  • James Dickson Innes, 'Arenig, North Wales' 1913
    James Dickson Innes
    Arenig, North Wales 1913
    Oil on wood
    support: 857 x 1137 mm
    Presented by Rowland Burdon-Muller 1928
  • Henri Matisse, 'André Derain' 1905
    Henri Matisse
    André Derain 1905
    Oil on canvas
    support: 394 x 289 mm
    frame: 550 x 471 x 75 mm
    Purchased with assistance from the Knapping Fund, the Art Fund and the Contemporary Art Society and private subscribers 1954© Succession Henri Matisse/DACS 2010

In colour theory complementary colours appear opposite each other on colour models such as the colour wheel. The colour complement of each primary colour (primaries are red, yellow and blue) can be obtained by mixing the two other primary colours together. So the complementary of red is green (a mix of yellow and blue); the complementary of blue is orange (a mix of red and yellow); and the complementary of yellow is violet (a mix of red and blue).

Artists began to become particularly aware of the significance of complementary colours after the development of scientific colour theory in the nineteenth century. This theory played an important part in the development of impressionism and post-Impressionism as well as fauvism and much modern painting thereafter. The impressionists were the first to note that shadows are not neutral but are the complementary colour of the light that throws them. So yellow sunlight throws a violet shadow. This can be seen very well in Claude Monet’s Woman Seated on a Bench in the crease of her arm and the pool of shadow at her feet.