70 mm Grandeur film, also called Fox Grandeur or Grandeur 70, is a 70mm widescreen film format developed by the Fox Film Corporation and used commercially on a small scale in 1929–31. It was a forerunner of the Todd-AO 70mm system which was introduced in 1955 and is still in limited use (albeit with significant modifications) today.
A small number of shorts and features were produced in Grandeur 70. These included several issues of Fox Movietone News called Fox Grandeur News first shown May 26, 1929. Features shot in Grandeur include Fox Movietone Follies of 1929, the musical Happy Days (1929), directed by Benjamin Stoloff, Song o’ My Heart (1930), a musical feature starring Irish tenor John McCormack and directed by Frank Borzage (Seventh Heaven, A Farewell to Arms), and the Western The Big Trail (1930), directed by Raoul Walsh, in which John Wayne played his first starring role.
Song 'o My Heart was double-shot in both conventional 35mm and Fox Grandeur, with all action and singing performed separately for the two processes. Production began in November 1929, and the 35mm version debuted on March 11, 1930, in New York. The Grandeur version, however, shipped from the labs on March 17, 1930, was never released and may no longer survive, according to film historian Miles Kreuger.