In the early nineteenth century Scottish scientists James Clerk Maxwell and David Brewster played a major part in the development of the techniques of photography. Pioneering photographers included chemist Robert Adamson (1821–1848) and artist David Octavius Hill (1821–1848), who as Hill & Adamson formed the first photographic studio in Scotland at Rock House in Edinburgh in 1843. Their output of around 3,000 calotype images in four years are considered some of the first and finest artistic uses of photography. Other pioneers included Thomas Annan (1829–1887), who took portraits and landscapes, and whose photographs of the Glasgow slums were among the first to use the medium as a social record. His son James Craig Annan (1864–1946) popularised the work of Hill & Adamson in the US and worked with American photographic pioneer Alfred Stieglitz (1864–1946). Both pioneered the more stable photogravure process. Other important figures included Thomas Keith (1827–1895), one of the first architectural photographers, George Washington Wilson (1823–1893), who pioneered instant photography and Clementina Hawarden (1822–1865), whose posed portraits were among the first in a tradition of female photography.