Brewster on chess. 1840s calotype salted paper print of British physicist Sir David Brewster (1781-1868) playing chess. The print is dated July 1842. Brewster wrote on chess in his work 'Letters on Natural Magic' (1832), two pages of which discussed the celebrated chess automaton 'The Turk', exhibited from 1770 to 1854. Photographed by British pioneer of photography William Henry Fox Talbot (1800-1877). Calotypes used paper coated with silver iodide to capture photographic images. Salted paper prints were produced using paper coated with silver chloride. Both photographic processes were invented by Talbot.