Botanical specimen, c 1841.
© Royal Photographic Society/National Media Museum/Science & Society Picture Library
Photograph taken by William Henry Fox Talbot (1800-1877). Fox Talbot invented the first negative/positive process for producing photographs between 1835 and 1839. 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.