Curtis Charles Senf (1873–1949), who signed his work C.C. Senf, was an American commercial artist and pulp illustrator. Born in Prussia, he came to the United States with his family in 1881 and grew up in Chicago, where he studied at the Art Institute. He later worked in commercial illustration and advertising, including an art agency he established with Fred S. Gould.
Senf became closely associated with Weird Tales. Beginning in 1927, he supplied pen-and-ink interior illustrations and painted 45 covers for the magazine; his final cover appeared in July 1932. He subsequently returned to commercial art in Chicago. His career links the city’s advertising trade with the visual identity of an influential fantasy and horror pulp.