The latest digital imaging techniques are literally throwing new light on the ingenious variety of materials that have been used over the centuries to create artists' paint pigments. A new exhibition at the National Gallery in London is looking at the history of colour making over time. Jane Reck has been finding out how preparations were given a helping hand with a state-of the art positioning easel that provides the ability to examine great works of art in unprecedented detail. Like this podcast? Please help us by supporting the Naked Scientists