Mastering Colour and other tricks

High definition colour feels like an entirely modern invention. Saturated manipulated photos, flat screen LCD tvs and 3D cinematic experiences combine to produce a visual pummelling apparently like never before. We have become so accustomed to synthetic colour that we take it for granted, like a cake addict, we are immune to the occasional treat.

So when we emerged blinking from the national gallery basement last night, our eyes had been reset and our brains reattuned to the special nature of the colours around us. The ridiculously blue cock and the bright flags of Trafalgar Square shining in the sunshine had taken on a new significance. They seemed to be a continuation of what we'd seen in Making Colour. A colour wheel of life, perhaps.

Vibrancy and rich texture is almost a given when talking about the National Gallery collection. But in a pre 19th century world with a limited synthetic colour palette, the scientific explanation for the silky blues, red velvets, green damasks is an eye opener. Now sadly murky landscapes would have glistened with spring flowers; sallow complexions would have been rosy pink. Over time the colours have reacted with internal and external chemicals, and we are left with paintings that have mellowed with age. Only the most expensive materials remain constant; lapis and gold. Proving the adage, at least in art, that money talks, and speaks to us over the centuries.

Recently I've been looking intensively at an object of art decorated with one of the most organic materials available. Using thirty different types of wood, European and exotic, the marquetry maker 'painted' a wide range of effects, emotions, and environments. Careful selection of wood colour and grain, with a small amount of chemical knowhow for adding shades of green, has resulted in an artwork as richly 'coloured' as any mineral based painting. And I have no doubt that it has experienced inevitable colour deterioration.

This is not something that I would have necessarily thought about prior to the exhibition but I am curious about how much wood fades. How much colour has it lost, given that it looks, to my eyes, richly vibrant and perfect? Kept in the right conditions, away from direct sunlight and munching beasties, with care I imagine wood 'living' on indefinitely. It's never going to be as stable and permanent as a painted slice of lapis but it will outlive us.

The most astonishing painting was kept for the end of the exhibition. It's incredible  effectiveness used gradations of the most simple tones. Lamp black and lead white artfully applied produced a shimmering covering for Mary Magdalene. This proves that the brain is easily fooled by the simplest brush tricks. I feel that there is a warning here. I'm sensing I'm now inserting or reading colours into parts of the wood which aren't actually there; my eyes have adjusted to the woods. In that image I saw silver. Silver which is more real than the tarnished grey metal on the Uccello painting next to it.

This exhibition is infinitely fascinating from a science of art point of view. To see the chemical analysis, and the lethal lengths to which artists went to give their illusions life. But above all it alerts you to the fact that your brain is easily tricked. Furthermore if you're going to look at some thing for a long time, you need to step back because you're probably seeing something that isn't there.