An interesting process from before the 1st World War was UTOCOLOR. Dr. J.H. Smith of Zurich, Switzerland introduced Uto color paper as long ago as 1904. It worked on the principle (which Dr. Smith called) of the Bleach Out law."A coloured body sensitive to light will only be affected by the light it absorbs, but not by the light of it's own colour". This means, as regards to the process: that Red light will destroy a Cyan dye and leave red dye, and so forth with other colours. This was by no means an original theory. Grothus had written about a theory not unlike this as long ago as 1819. The paper was used to make prints from the very few colour transparencies of that time, notably Autochrome. There was no dev. or fix, after exposure to the trans. by contact printing, the paper was "stabilised" (!) in a Uto bath. I suppose today's equivelant would be a reversal colour print paper. Although there were improvements, (1906, 1911) I beleive the process died out before the 1st World War. But Utocolor marked the beginning of the "Silver Dye Bleach" process. The principal name associated with the process is Dr. Bela Gasper. "Gaspercolor Opaque" became "Cilchrome" then "Cibachrome" .