Two men playing chess, c 1842.

Photograph by William Henry Fox Talbot (1800-1877) showing a game of chess, probably between Henneman and Pullen. Talbot invented the first negative/positive process for producing photographs between 1835 and 1839. This meant that, for the first time, any number of prints could be made from the same shot by transferring the negative image on to special paper to make a positive print. Talbot's process for achieving this is known as the calotype process.