This was the first major Hollywood film to be shot in Panavision. The Panavision process faced its first major test when Audrey Hepburn expressed worries that the widescreen process would distort her already square face. Test footage made in Panavision revealed this not to be the case, and reportedly received applause when it was shown for Hepburn and others in a test screening.
Heitor Villa-Lobos composed a large-scale score for the picture, but most of it was rejected by the studio. Bronislau Kaper was commissioned to write a new score, but insisted on incorporating some of the Villa-Lobos music. Villa-Lobos reworked his score as a concert suite, "Floresta do Amazonas (Forest of the Amazon)".