Wayne Sleep, the choreographer and old friend, put it more simply. Hockney never leans on what he already knows. He pushes every medium he touches, even a fax machine if it keeps him working. Joe Simon, a friend of both Hockney and me, offered a glimpse of that drive. He told me David’s greatest dislike is looking backwards. “If it doesn’t push him forward he doesn’t rate it.” Joe’s portrait is my favourite in the room. I know him well and saw the person I know framed in gold, his name painted neatly like a celebration. Each sitter feels promoted, honoured even, as though Hockney is advertising the people he loves. He reshaped Joe’s face with a slab of white paint and left the correction visible. It is an honest act, not a flourish. Joe said sittings can feel intimate. David leans close, squints, clicks his tongue, looks from eyes to canvas, then when he is done he smiles and lights a cigarette.