The textbook is specific about Life magazine (begun 1936) and Look magazine (begun 1937) as the large-circulation picture magazines that “provided an outlet and a vast audience for documentary work.” The Great Depression of the 1930s provided the subject matter: the Farm Security Administration (FSA) under Roy Stryker commissioned photographers including Walker Evans, Arthur Rothstein, Russell Lee, and Dorothea Lange to document Depression-era America. World War II further developed photojournalism — photographers including Margaret Bourke-White, Robert Capa, W. Eugene Smith, and Edward Steichen documented the global conflict. The development of the 35mm “candid” camera by Oskar Barnack (Leica, first marketed 1925) made documentary photographers “infinitely more mobile and less conspicuous.” Colour film for transparencies was introduced in 1935; the Polaroid Land camera in 1947.