Calotype by William Henry Fox Talbot (1800-1877). The player on the left is probably the photographer Antoine Claudet (1797-1867). Talbot invented the negative/positive proces for producing photographs between 1835-39. 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; these prints were called calotypes.
© National Museum of Science & Media / Science & Society Picture Library