A couple of researchers test out David Hockney’s theory that Old Masters used optical devices to assist in their work. They registered a van Euck painting using a computer. “If the two arms had been painted in perfect perspective they would align well; they did not. Therefore the Arnolfini chandelier is not painted in perfect perspective. If van Eyck had used a concave mirror to project an image of a chandelier onto his canvas and had then traced the image with a pencil, later covering over the evidence with paint, his chandelier should be really accurate. Why cheat if you can’t get good results?”