Schneewittchen, a film by Stanley Schtinter based on a text by Robert Walser, opens with a shot of a man in black lying in a field of snow, supine, one arm thrown out. The scene emulates photographs taken on Christmas Day 1956, when Walser left the asylum where he had spent 23 years to go for a walk, never to return. The images have inspired many reconstructions. The one in Schneewittchen has the director playing the writer. Not everyone who came to the film’s UK premiere at the BFI last month realised that Schtinter was in it.