Earliest published representation of a photograph, 20 April 1840.
© Science Museum / Science & Society Picture Library
A William Fox Talbot (1800-1877) photogenic drawing of a fern published in 'The Mirror of Literature, Amusement and Instruction'. Fox Talbot invented the negative/positive process for making photographs between 1835-39. Any number of prints could be made from the same shot by transferring the negative image on to special paper; these prints were called calotypes or salt prints.