hectograph

thumb|A 19th-century hectograph advertisement thumb|Unissued stock certificate of the Hektograph Manufacturing Company of New York, 1880s

Hectography is a printing process that involves transfer of an original, prepared with special inks, to a pan of gelatin or a gelatin pad pulled tight on a metal frame. A machine employing this process is a hectograph, also known as a gelatin duplicator or jellygraph.