David Hockney: Drawing from Life review – stripping subjects down to their gym socks

National Portrait Gallery, LondonFrom joyful sketches of old friends to a nude meeting with Picasso – when Hockney wields his pencil we see the undisguised truthWhen it comes to wielding a pencil, an etching burin or just a felt pen, David Hockney has no rivals. Lucian Freud’s etchings bore me senseless, Francis Bacon barely doodled, but Hockney is a graphic master. His retrospective of a life of portrait drawing is the most dazzling display of his art I have ever seen.Forget the ran