By January 2022, pre-production was underway in New Mexico, where a two-day casting call was held in Santa Fe and Los Alamos for residents, military personnel, and scientists.
In February, another casting call was held. Hoyte van Hoytema served as cinematographer for the 57 days of principal photography that began in late February 2022. Gary Oldman stated that he would be on set for one day in May to film “one scene and a half page.” As part of a vision from Oppenheimer, Nolan’s eldest daughter, Flora, filmed a scene in which she portrayed a young woman in an explosion. His intention in including the set was to convey that “the point is that if you create the ultimate destructive power, it will also destroy your loved ones,” he believed this was the most effective way to say it.
The film was shot on a 65 mm and 65 mm IMAX combination. It is also the first film to use IMAX black-and-white photographic film, which Kodak and FotoKem developed explicitly for the film. During the second week of April, the Institute for Advanced Study in Princeton, New Jersey, served as the location for filming. Filming occurred in California, primarily on the University of California, Berkeley campus. The production crew filmed scenes in Belen, New Mexico, with Murphy climbing a replica of the Manhattan Project’s original 100-foot steel tower, and filming concluded in May 2022.
They were filming with actual explosives instead of computer-generated imagery to recreate the Trinity nuclear test. Gasoline, propane, aluminum powder, and magnesium were used to create a specific set. The miniatures used for practical effects were referred to as “ligatures” by the film’s special effects supervisor, Scott R. Fisher because the special effects team attempted to make the models as large as possible. The team utilized forced perspective to make the models appear closer to their intended size. For the film, a 1940s-style town was constructed from scratch because modern Los Alamos looks very different today. The interactions between atoms, molecules, and energy waves and the depiction of stars, black holes, and supernovas have been visualized using practical techniques. Nolan asserted that the film has no computer-generated effects. Additionally, scenes were filmed in Oppenheimer’s restored original cabin. Murphy’s performance as Oppenheimer on set impressed Kai Bird.