I really must say something regarding the van Eyck. As a painter, I can tell you how he did the painting. Let me point out some things about the work. The cloth and the metal objects are way better than the flesh. Why? The people move. This alone says he did the work without optical devices/photos, etc. He could spend days getting the non-moving things right. His perspective is way better than many later painters, by the way. I think he tried harder and understood more. I assure you he would have worked out this complex object Mr Hockney
mentions slowly on paper and likely tranferred it to canvas (from cartoon to canvas or panel) just as Bouguereau did years later with his figures. If painters don't do this the canvas is cluttered with the lines, adjustments, ERRORS that happen while we draw.
It is the weak stuff in the van Eyck like the dumb hands that tell me the work WAS done from life. A photo or optical device would have made all parts equally well done. Maybe some other painters can say this better than me ... Virgil? Juan?
