Christopher Nolan eschewed CGI in favour of practical effects for his latest film.

By Patrick Cremona

Published: Friday, 14 July 2023 at 12:00 am


Given that Christopher Nolan’s new film Oppenheimer is a character study of the man credited as the ‘Father of the atomic bomb’ it’s no spoiler to say that it includes a couple of almighty explosions.

Nolan has been clear during interviews that no CGI was used to create these scenes – which at one point in time led to some rather outlandish speculation that the director had detonated an actual atomic bomb in New Mexico during production.

Of course, those rumours don’t actually have any bearing in reality, and Nolan in fact worked extensively with Oscar-winning special effects supervisors Scott Fisher and Andrew Jackson to create the nuclear fire and mushroom cloud that is seen in the film.

Read on for everything you need to know about what effects were used for these sequences.

How did Christopher Nolan’s Oppenheimer film atomic bomb sequences?

If you’re familiar with Nolan’s work, you’ll probably already be aware that he has a strong preference for practical effects – and so it’s no surprise that he was determined to avoid resorting to CGI for the atomic bomb sequences.

Speaking in the film’s press notes about putting together the Trinity test sequence, the director said that he always knew it “was going to be one of the most important things for us to figure out”.

He explained: “I had done a nuclear explosion via computer graphics in The Dark Knight Rises, which worked very well for that film. But it also showed me that with a real-life event like Trinity, which was well documented using new cameras and formats developed for recording that event, computer graphics would never give you the sense of threat that you see in the real-life footage.

“There’s a visceral feeling to that footage. It becomes tactile, and in becoming tactile it can be threatening as well as awesome. So that was the challenge. To find what you might call analogue methods to produce effects to evoke the requisite threat, awe, and horrible beauty of the Trinity test.”

"Cillian
Cillian Murphy is J Robert Oppenheimer in Oppenheimer, written, produced, and directed by Christopher Nolan.
Universal Pictures

And so a number of experiments were carried out by Jackson and Fisher, which included such relatively low-tech ideas as smashing ping pong balls together and throwing paint at a wall.

These experiments were filmed in super-close-up using small digital cameras at various frame rates before Nolan would provide feedback and ask them to work out a way to recreate these effects on a bigger scale – using massive IMAX cameras.

Alas, if you’re wanting to know exactly what techniques were eventually used, you’re out of luck: Nolan and co have opted to keep the process top secret, which almost serves as a nod to the Manhattan Project itself.

But whatever the techniques, cinematographer Hoyte van Hoytema said that Jackson and Fisher’s unit was “one big science project” adding that he was “very jealous that they got to play around so much with all that kind of stuff”.