Oppenheimer’s 'real' bomb sequence was created using balloons – and an aquarium

gamesradar.com:

Oppenheimer may have blown away all expectations at the box office, but its climactic scene – involving the atomic bomb being tested for the first time at Los Alamos – is something that’ll likely linger for far longer than opening weekend.

Now, Oppenheimer director of photography Hoyte van Hoytema has revealed how that incredible sequence came to life. Partially revealed, anyway – he’s still keeping some of Nolan’s secrets.

"Obviously, we couldn’t make an explosion the size of the actual explosion so we used trickery," Van Hoytema told Variety. 

Van Hoytema outlined the process, which featured everything from balloons to ping-pong balls – and camera tricks.

"We created science experiments. We built aquariums with power in it. We dropped silver particles in it. We had molded metallic balloons which were lit up from the inside," Van Hoytema said. 

"We had things slamming and smashing into one another such as ping-pong balls, or just had objects spinning…We had long shutter speeds, short shutter speeds, wide negative color, negative overexposure, underexposure. It was like a giant playground for all of us."

Nolan had previously told Total Film that he and his team recreated the Trinity test "without the use of computer graphics," something which he admitted was a “huge challenge.”

The director explained: "Andrew Jackson – my visual effects supervisor, I got him on board early on – was looking at how we could do a lot of the visual elements of the film practically, from representing quantum dynamics and quantum physics to the Trinity test itself, to recreating, with my team, Los Alamos up on a mesa in New Mexico in extraordinary weather, a lot of which was needed for the film, in terms of the very harsh conditions out there