The Open Door, 1843.
© National Media Museum / Science & Society Picture Library
Photograph by William Henry Fox Talbot (1800-1877). Salted paper print from a calotype negative. Fox Talbot invented the negative/positive proces 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. Dimensions 14.2 x 19.4cm