This exhibition opened in June, but I’ve only just got round to seeing it. Although it focuses on painting rather than textiles, it’s definitely worth a visit.
It begins with a brief introduction to the concepts of primary colours and the colour wheel, and how painters over the years exploited the combinations of complementary colours (those which are opposite each other on the colour wheel, such as purple and yellow, or green and red) to create striking visual impressions.
This is followed by sections on each of the main colours – blue, green, yellow, red and purple, plus gold and silver.
The earliest pigments were mostly from ground-up minerals. Lapis lazuli, or natural ultramarine, used for blue, was at one time more expensive than gold, so became popular for painting the robes of the Virgin Mary, as a sign of devotion. Red vermilion (cinnabar) was a mercury ore, green came from verdigris, while ochre produced yellow.
The Virgin in Prayer by Giovanni Battista Salvi
The Romans famously made Tyrian purple from shellfish, but their method doesn’t seem to have outlived them. However, other creatures used to produce dyes came to be used for paint pigments too, notably the “red lake” pigments such as cochineal, kermes and stick lac – all came from types of insects (madder and brazilwood were other sources).
Not all pigments were equally stable. Smalti, a form of cobalt used as a cheaper alternative to ultramarine, was not very stable, resulting in grey skies rather than blue in many old paintings.
Similarly, the red lakes derived from dyes tend to fade in light. Analysis by the National Gallery shows that the grey sheet on which Venus reclines in Velázquez’s famous painting was originally purple – but the red in the mixture of pigments he used has faded over the years.
The Toilet of Venus by Diego Velazquez
The colour also depends on the medium used to mix the pigments. In Renaissance Italy they used green tempera, or egg yolk, as the base colour for flesh, with red and white highlights on top. However, the red and white have faded over time, resulting in some figures looking literally green around the gills. On the other hand, verdigris mixed with oil discolours to a dark brown or black, making landscape or trees look very dark rather than green.
The development of more stable synthetic pigments varies according to colour. Artificial vermilion was available as early as the 9th century (or possibly before), while yellow pigments were manufactured in Renaissance times from compounds of lead, tin and antimony, originally for use in making ceramics. Anthony van Dyck’s portrait of Lady Elizabeth Thimbelby shows her sister Dorothy resplendent in yellow silk.
Lady Elizabeth Thimbelby and her Sister by Anthony van Dyck
But it wasn’t until the 19th century that synthetic versions of ultramarine, emerald green, verdigris and purple (mauveine) were produced (although Prussian blue was available in the 18th century). No longer did artists have to painstakingly grind up their own pigments – paints could be mass produced in consistent colours and sold in tubes.
Greater accessibility to a greater variety of colours led some painters to change their approach to painting. As Renoir said, “Without tubes of paint, there would have been no Impressionism”.
There’s also a short film looking at the way we perceive colour, including a fascinating demonstration of chromatic adaptation (there’s a similar example here).
Making Colour runs at the National Gallery until 7 September 2014. I highly recommend it – you’ll never look at a painting in the same way again!