828 film was Kodak’s unperforated 35mm paper-backed roll film, introduced in 1935. 828 was intended to avoid some of the problems of the early perforated 35mm films. The smaller diameter spool and lack of need for a sprocket allowed for much smaller camera designs. Kodak’s Bantam camera series used 828 film.
Other paper-backed 35mm film formats have included Bolta and the film Konishiroku produced for the Konilette.