The Tri-Ergon sound-on-film system was developed from around 1919 by three German inventors, Josef Engl (1893–1942), Joseph Massolle (1889–1957), and Hans Vogt (1890–1979). The system used a photoelectric recording method and a non-standard film size (42mm) which incorporated the sound track with stock 35mm film. With a Swiss backer, the inventors formed Tri-Ergon AG in Zurich, and tried to interest the market with their invention. There were a number of companies which used the Tri-Ergon name: