Painter, printmaker, and sculptor. A native of Minden, Germany, he studied art in Hannover. After coming to the United States in 1925, he worked for federal art projects during the Depression. A government-sponsored painting, Abstract #2 (Smithsonian American Art Museum, c. 1934), suggests the power of industry by representing a single worker amid semi-abstracted machine and factory forms, such as gears, wheels, a gauge, smokestacks, and a water tower. Also during the 1930s, responding to constructivism, cubism, and other forms of modern expression, Kelpe refined a purely abstract style. An untitled work from about 1938 (Brooklyn Museum, on loan from the New York City Housing Authority) presents hard-edge geometric forms in a simple but dynamic arrangement that advantageously shows Kelpe's sensitivity to color. Pinks ranging from salmon to lavender, along with a creamy yellow, dominate the middle of the canvas, against backdrop planes of black, brown, and gray. Other works include organic forms, sometimes carrying surrealistic overtones. His abstract constructed reliefs from the 1920s pioneered works of this type created in the United States. He numbered among the founding members of the American Abstract Artists. In the 1950s Kelpe earned a PhD in art history at the University of Chicago. He taught at several schools, including the University of Texas in Austin, where he died.