One of the oldest photos in the archive is this c.1880 image of Mr Holman and his employees, printed on iron.
Tintypes or Ferrotypes were an early form of photograph. A sheet of thin, varnished iron (not tin, despite the name) was coated with photographic emulsion and exposed to light. This picture from the Geoff Holman collection shows his great grandfather, Thomas Holman, surrounded by employees of Holman Brothers Ltd.