At John Stezaker’s studio in Kentish Town an entire wall is given over to a photographic archive the artist bought about thirty years ago. Britain’s cinemas had been going out of business for decades, and with them the picture agencies that supplied the industry with film stills and actor portraits. Stezaker snapped up the contents of one such doomed establishment, but has done nothing with them since. (Though he has plans, he says.) Look around the studio, and you get a queasy sense of the fate that might await those black-and-white prints. There are forgotten starlets half decapitated, neatly enucleated character actors, scenes from long-lost B-movies invaded by lurid portions of landscape or Kodachrome bouquets. And here and there a scalpel, threatening the surface of an intact print.