James Franco was cast to play Ralston — cast after Cillian Murphy was reportedly approached first, a detail that invites speculation about which film might have resulted. Franco committed to the role with evident intensity. He described the physical demands of the shoot as leaving him with real scars, and said the experience became “more of an experience that I went through” than a conventional performance. The physical realism of the key sequence was achieved through the work of makeup effects designer Tony Gardner and Alterian, Inc., who created prosthetic effects that the director considered essential to the audience’s investment in the material. Franco reportedly found seeing the prosthetic’s simulated blood genuinely difficult to look at, and his reactions in those scenes were, by his own account, genuine responses rather than performed ones.
Danny Boyle made several directorial choices that shaped the film’s aesthetic character. He hired two cinematographers — Anthony Dod Mantle, who had worked on Slumdog Millionaire, and Enrique Chediak — and divided the shooting roughly equally between them, creating a visual texture that combined the approaches of two distinct artists. He planned to open the film without dialogue, establishing the visual environment before characters and language intruded. He brought A. R. Rahman back from Slumdog Millionaire to compose the score, creating a musical continuity between two very different films united by a shared focus on extreme human experience.
The film premiered at the Telluride Film Festival on September 4, 2010, and subsequently at the Toronto International Film Festival on September 12. The response at Telluride included a well-documented incident: two audience members required medical attention during or after a screening — one was carried out on a gurney after becoming lightheaded, and another had a panic attack. Reports of audience members fainting or becoming physically distressed followed the film through subsequent screenings at Toronto and at a Pixar-hosted showing. The reports became part of the film’s marketing context, an inadvertent testament to the realism of the amputation sequence.