This article is from Artists and Illustrators magazine.
Its great article, and I just had to re-post it.
Colour theory is a tricky subject for artists. The problems arise as soon as we start putting paint on our palette. What about hues, tones, tertiaries or warm and cool colours? How many colours do we really need? And how can we use the expertise of scientists to inform our practice as artists?
Experts in science and art have long agreed that a colour exists not as an isolated entity but through its relationships with other colours. Last century, Josef Albers developed a set of exercises using coloured paper to see and appreciate colour relationships, taking us full circle to Aristotle’s observation that “the appearance of colours is profoundly affected by their juxtaposition with one another.”
Such juxtaposition starts on the palette. A painter’s palette, can, and should, be a thing of beauty, for it contains the essence of the relationships and excitement that is to unfold. A few carefully prepared and considered colours go a long way. We don’t need what Matisse dismisses as “an avalanche of colour” – Bridget Riley often used only three colours on a canvas because she knew that an individual colour changes its identity through its juxtaposition with another.
The goal is to set up colours that sing; that resonate with each other and with our intentions. Not so easy perhaps, but if even Van Gogh worried about how to use colour, we can at least take reassurance that we are in good company.
Primary and Secondary colours
In colour mixing, primary colours are the three that cannot be made by mixing other colours together – red, blue, and yellow. If you mix two primary colours together, you create a ‘secondary’ colour. Mixing blue and yellow creates green, and so on.
The complement of a primary colour is a mix of the remaining two primaries. So the complementary colour of red is green, for example. When placed next to each other, complementary colours will appear brighter and more intense. In the 19th century, Goethe said the shadow of an object should contain its complementary colour – for example, the shadow of a green apple will contain some red.
The Colour Spectrum
Sir Isaac Newton discovered that all colour comes from light but white and black were not part of this spectrum. When painting bright light, adding white paint tends to dull a colour, rather than doing the opposite. For highlights, we need adjacent colours on the spectrum, also known as analogous colours.
When a tube of paint says ‘hue’ on it – for example, cadmium red hue – it means that the colour will look almost identical to genuine cadmium red, but the pigment is something different. A paint labelled as a ‘hue’ is usually a cheaper or blended version, or maybe the original colour is no longer produced.
Warm and Cool Colours
The red-yellow side of the colour wheel is said to be warm. These colours appear to advance towards
you when viewed from a distance. The green-blue side of the colour wheel is said to be cool, and these colours appear to recede. A knowledge of how warm and cool colours behave is useful when arranging colours in a landscape to create an illusion of depth.
Colour and Tone
When tonal values are equal, for example a bright red next to a bright blue, we see the contrast between the colours clearly. However, when tonal contrast is strong, for example between a light yellow and a dark blue, the difference in hue is less noticeable as the opposition of light against dark dominates.