Autochromes Lumière
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The Autochrome Patent

The Autochrome Patent, A "Process of Colour Photography"
On December 17th, 1903, Auguste and Louis Lumière put in a request for a 15 year patent. At this time, the invention didn't yet carry the name Autochrome. It would take four years of work before being commercialised in Lyon, becoming the first colour photographic process produced on an industrial scale. The patent itself contained the following summary: "The invention consists of a stratified series of layers, characterised by the interposition, between the light-sensitive layer and the glass which acts as a support, of a layered screen composed of coloured elements as are described below, and having the effect of regulating at each point of the sensible layer the intensity of the impression, following the constitution of light rays at this point, according to which, after development and inversion of the negative, the plate shows an image in natural colours through its transparency."

Three Additions to the Initial Patent
Three additions went into completing the first patent. The first (n° 3891), requested on the 13th of January 1904, anticipated the possibility of a system of a single polychromatic strata. The second  (n° 4290), requested on the 9th of November 1904, focused on the employment of violet, green, and orange tinted particles. It also specified that the filling of the interstitial spaces could be realised with minute coloured particles or through the use of an opaque powder. The last addition (n° 7230), requested on the 5th of April 1906, was a matter of "obtaining continuity of the screen layer positioned between the sensitive strata and the glass support, without resorting to a filler of black power for the spaces remaining between the coloured particles... the coloured layer is subjugated at the same time as its support to a direct pressure or to a lamination that squeezes the adequately pliable, coloured granules, forcing them to fill in the spaces themselves."