Chicago-based Hawthorne Roofing Tile Company originally manufactured its tile from slabs by a hand-process. These concrete roofing tiles depicted in the 1929 Sweet's Architectural Catalog imitated French and Spanish clay tiles. They were produced with automated power-driven equipment, and the colors were impregnated on the tile surface. (Sweet's Architectural Catalogue, 1939. Courtesy of the Sweet's Group-McGraw Hill Companies, Inc.)