I realised on Friday that the big exhibition of Francis Bacon 'Portraits and Heads' which I've been meaning to visit all summer was about to end, so I went to see it. I used to really like Bacon's painting but lately I've felt less enthusiastic for some reason. I think I hoped that seeing this show would rekindle my enthusiasm, and in a way it did. However, I don't think seeing his paintings en masse is necessarily a good thing. As an artist he's pretty much a one-off, a maverick, and that may be one reason why his paintings seem to work best in isolation or small groups. Seeing so many hanging cheek by jowl tends to emphasise his stylistic limitations. It's not that when you've seen one Bacon you've seen them all, but in the portraits you do become aware that he constantly projected his own tortured self-image onto his sitters. Even so, I came away with a renewed respect for him; for the uncompromising way in which he explores the mysteries of painting itself, and - like his Irish contemporary, Samuel Beckett - the darker side of existence. Bacon's vision may be bleak, but the portraits from the middle of his career (usually 'studies', in groups of three) are strangely beautiful too.