Omnicolore was a very early additive colour photography process that produced positive images on glass plates.
It was based on a process patented by Louis Ducos du Hauron in 1906 and was introduced to the market in 1907 by the Jougla company in France, a few months before the Autochrome process was introduced by the Lumière brothers.
Omnicolore used the screen process like Autochrome, but used a grid of lines (blue lines with broken lines of red and green) to form the colour screen rather than random starch grains. This made them more sensitive than Autochrome and allowed for shorter exposure times, but the colour quality was reduced over Autochrome.
Jougla produced Omnicolore plates in a range of sizes, and also in stereoscopic formats, but due to competition in the small market for colour photography, Jougla merged with Lumière in 1911 and the Autochrome process won out with Omnicolore disappearing in 1912.