Toronto. Once daguerreotypes gave us fine detail in mono colour or hand painted images, the holy grail became automatically coloured photos.
The first processes used various filters over a common mono colour (black and white) plate. The best commercial process in the early 1900s was the Autochrome. Created by the Lumiere brothers in France, Autochromes created additive process colour slides using dyed potato starch bits sprinkled on standard dry plates.
The plates were very slow like all the additive processes, and with relatively large potato starch bits, rather grainy. This process resulted in a hazy, dreamy colour image.
PHSC member and contributor to this site, Sarah Shrigley, reminded me of the Autochromes and offered this link to gorgeous samples taken the period from 1907 – 1925 by British photographer John C Warburg (1867 – 1931) and displayed on the Mashable web site.