"Pochoir is a refined stencil-based technique employed to create prints or to add color to pre-existing prints. It was most popular from the late 19th century through the 1930's with its center of activity in Paris. Pochoir was primarily used to create prints devoted to fashion, patterns, and architectural design and is most often associated with Art Nouveau and Art Deco." -- "The pochoir process is the hand-coloring of an individual black outline prints. The was done with the help of a thin zinc or copper cut-out stencil guide. Each color is applied separately brushed by hand on each print, one stencil for each color."Vibrant Visions: Pochoir Prints in the Cooper-Hewitt, National Design Museum Library - at the Smithsonian Institute.
Also: George Barbier at artophile and Pochoir artists at Art Deco Prints & Posters. [and previously]