We have already touched on the topic of complementary colours a few times on this website. But just what makes this complementary effect so special? Underlying this phenomenon is a physiological explanation. The optic nerve that translates incoming information into shapes and colours has a very distinctive property that helps it to process colour. Each colour that falls upon the retina is perceived as if it were an attack that must be weakened. The eye does this by instantly creating a matching filter in a complementary colour in order to protect the optic nerve from irritation. This filter in a complementary colour acts to somewhat neutralise the original colour. Try the following experiment on a sunny day. Take a large sheet of clean white paper, and paint a bright red dot on it. Hold the paper in the sunlight and stare closely at the red dot for 20 seconds. If you then close your eyes, you will see an after-image of the dot; instead of red, however, it will be green, which is the complementary colour of red. The reverse is also true – a bright green dot will produce a red after-image. If you take one of the other two primary colours – blue or yellow – the after-image formed will be in their respective complementary colours, orange and violet.
You may be asking yourself ‘So what?’ Yet painters who understand this phenomenon, and take it into consideration in the colour composition of their paintings, can achieve interesting effects. The previously mentioned physiological phenomenon means that complementary colours have a strong effect on each other: a splash of orange on a blue plane reinforces both colours. A patch of green against a red background produces a brighter contrast than it would against a brown background. Take a good look at Van Gogh’s paintings, especially those from his time in the south of France, such as Self-Portrait with Bandaged Ear. The background in this self-portrait is made up of two main colours: orange and red. These form a powerful contrast to their complementary colours blue, used in the hat, and the green of the overcoat. This was a deliberate choice of colours by Van Gogh, as we know that the walls in his studio in Arles were white.
This use of contrast can also be more subtle and varied, as in pointillist paintings, a technique Van Gogh experimented with during his time in Paris. Pointillism works because when we look at a painting, we do not keep our eyes tightly fixed on one point. Instead, our eyes roam across the image absorbing what we see, and this brings our optic nerve in a constant state of confusion. It has to continually adapt and change the filter in an instant. This produces an interesting effect that is particularly heightened in pointillist paintings, a kind of optical vibrato without actual movement. Take Van Gogh’s painting Bank of the Seine, painted in the summer of 1887, a fine example of his experimentation with painting using stippling, which in his case would evolve into a technique using stripes. In this work small dots of red light up against the green planes of the leaves, pink hues are used near to soft shades of green, stripes of orange in varying degrees of brightness have been placed alongside blue ones and so on. Every square centimetre is a symphony of colours.
This technique has many more practical applications that can be used to good effect. If, for example, a single colour – orange – is predominant in a painting of a field of wheat, then grey stripes of shadow among the wheat will be perceived as blue-violet, even if the painter has used a neutral shade of grey. This is because the optic nerve activates its blue-violet filter to compensate for the orange-yellow colour, and the grey is then seen through that filter. This is known as simultaneous contrast. So a painter who has a good understanding of this process and uses it to his advantage in choosing the colours for shadow areas can produce brilliant effects.
Pointillists tend to work with large planes, and are able to use complementary colours and simultaneous contrast to create very interesting colour perceptions, such as a fascinating tone of grey emerging from a plane filled with carefully positioned orange and blue dots. To really see this effect at work, start by looking at the painting from a distance, and see how it changes as you get closer.
There is much more that can be said about these physiological effects on the eye and the publications on this subject by Johannes Itten (1888-1967), artist and teacher, make fascinating reading. Wikipedia also lists interesting links to information on different types of colour contrast.
By Rob Bouwman and Teio Meedendorp