Many, including Fred Astaire, blamed director Francis Ford Coppola for cutting off Astaire's feet during filming of his dancing scenes, but it was Warners who decided, after the filming had been completed in 35mm, to convert the film to the wider 70mm and promote it as a "reserved-ticket roadshow attraction." This was achieved by cropping off the tops and bottoms of the film frame, including some shots of Astaire's footwork.
Because of its satire on racism, this popular 1947 Broadway musical was considered such a hot potato in Hollywood that studios would not touch it unless they were allowed to change the story. Its original creators, E.Y. Harburg, Burton Lane and Fred Saidy, held out and by 1968 it was able to be filmed with very few changes.
According to the commentary track on the DVD, choreographer Hermes Pan was fired part of the way through production because Francis Ford Coppola felt his choreography was too old-fashioned. Pan was replaced by a much younger choreographer, Claude Thompson, who was familiar to many of the dancers in the film.
The original Broadway production of "Finian's Rainbow" opened at the 46th Street Theater (since renamed the Richard Rogers) on January 10, 1947, ran for 725 performances and won the 1947 Tony Awards for the Best Actor (David Wayne), Music Director and Choreography.
One early attempt to film the musical was as an animated feature to be directed by John Hubley. It was during development of this unfinished project that Hubley first collaborated with future wife Faith Hubley (then Faith Elliot). The soundtrack for the animated film was already completed and the entire film had been storyboarded. The voice talents included Frank Sinatra (as Woody), Barry Fitzgerald (Finian), Jim Backus (Senator Rawkins), Ella Fitzgerald, Louis Armstrong and from the original Broadway cast Ella Logan (Sharon) and David Wayne (Og). The project died when Hubley refused to "name names" when he testified before The House Un-American Activities Committee. Hubley was blacklisted and Chemical Bank, which was providing the financing, withdrew funding for the proposed film. Artwork done for the movie appears in the PBS documentary "Independent Spirits - The Faith and John Hubley Story" and the Sinatra prerecordings are available on the CD Box-set "Sinatra in Hollywood 1940-1964."
The actor and actress who played the roles of Finian and his daughter in the original musical were still alive at the time the movie version was made but died within a year of each other shortly after it came to theatres.
Not heard in the film is a soulful rendition of "Necessity," taken from the Burton Lane-E.Y. Harburg 1947 Broadway score and sung by Brenda Arnau with a chorus. Fortunately, this version has been preserved on the soundtrack LP from Warner Bros. Records, and more recently, on the soundtrack CD from Rhino Handmade.