14 October

David Hockney refers to the Ghent Altarpiece in his brilliant book on the possibly big use of lenses, mirrors and other optical technology by important painters, including Caravaggio. The Altarpiece is important says Hockney because it shows how much linear perspective has come to dominate how we think about images and space - this painting uses an entirely different type of perspective. Some simpletons have said it's a type of primitive perspective, but as Hockney says it's immensely sophisticated, giving the viewer the sense that everything in the painting is right at the front, so that there is a presence to every important element.