Autochrome taken in the garden of Observatory House, Slough, 1911.
© National Media Museum / Science & Society Picture Library
Photograph by Sir William Herschel. 1911 was an extremely hot summer, which caused the emulsion on the plate to melt. Autochromes were the first commercially available colour proces, invented by Auguste (1862-1954) and Louis Lumiere (1865-1948) patented in 1904 and marketed in 1907. A glas plate was covered with potato starch, dyed green, red and blue, producing a random pattern of coloured dots and then coated with emulsion. This plate was then exposed in the camera with the glas side toward the lens, so that the starch acted as a colour filter on the light before it reached the emulsion.