Photography - History of Photography

To John Herschell is due the use of the compound usually termed "Hypo"; really Sodium Thiosulphate; as a fixing agent. This was adopted in practice and its introduction marks an important epoch. Although glass plates had been used incidentally by Wedgewood and others in photographic experiments, the suggestion of their use, instead of paper, in producing negatives, seems to have been Herschell's also. The very important "Blueprint" or Ferroprussiate process, so extensively utilized in modern industrial and engineering work is another of his contributions to photographic progress.