Mat Collishaw can always find the intrinsically evil in photography. His subjects are often shocking and horrific – but it’s always the medium which is most disturbing. In The Eighth Day, Collishaw reproduces a photo of a real lynching found in an old book – but he does it in a monumental mosaic. Originally used in ancient times to immortalise gods, saints, and martyrs, mosaics were used to preserve timeless morals. But there’s something freakishly futuristic about Collishaw’s epic – black and white images are a modern invention, the miniscule tiles convincingly parody computer pixellation.