The following questions and answers are excerpted from a conversation that followed the NBR screening of Oppenheimer.

Subjectivity is very present in this film in many ways. The title is Oppenheimer as opposed to the longer, more academic title of the book. When you’re talking with Cillian about that and how you’re going to essentially be inside of his head for a lot of the film, what do you discuss about him embodying this man?
Christopher Nolan: I think the first and most important conversation was the one where we both agreed that we were not interested in some kind of impersonation. There’s a wonderful phrase from Ken Loach that he coined several years ago. He talked about the cinema of Madame Tussaud. There’s this idea that just by imitating or the facsimile of somebody, there’s inherent value in that somehow. And particularly with Oppenheimer, who was an iconic figure at the time. But the iconography is not even so well-known these days. I think Cillian slightly breathed a sigh of relief with that, that I was saying that we did not need an interpretation. We’re making a dramatic film, not a documentary. We’re not trying to impress people with the similarity between what you are doing and what you can see on YouTube archival footage. I think he found that freeing. That said, having all of these points of reference and having months to be able to work on that gave him something to sink his teeth into. Listening to the way the real man spoke, the way he dressed, the way he moved. I think for the best actors, after you cast them, there’s this period where we’re building sets, we’re traveling the world, figuring out how to do things. We’re very busy while they’re sort of left at home waiting. You know, there are hair and makeup tests or wardrobe tests, but it’s few and far between. Sometimes there’s stunt training. I believe that anything that gives an actor something to grab a hold of, to really work at will help them use that period productively. And he certainly came to set the first day with an incredible amount of knowledge and a very fully developed take on the character.

This is a film about consequences

Your physical sets are incredible and you’re well known to be someone who uses practical effects as much as possible. Emma, knowing that this is the case going in, what was your thinking about how to best produce these major set pieces? Especially the Trinity sequence. 
Emma Thomas: We had worked with an amazing visual effects supervisor before called Andrew Jackson. Particularly on Dunkirk, where we had many big sequences with explosions, but also with the planes and so on. We did as much of that as possible practically. We revisit perhaps slightly older methods of filmmaking. It works really well for us because the old becomes new again since the modern audience’s eye isn’t necessarily used to the way those effects look. On Dunkirk and then also on this film, the visual effects department very seamlessly integrates their work with the special effects department. In that pre-production period that Chris described, while Cillian was sort of getting his teeth into the character and we were location scouting and so on, we also had our visual effects and special effects departments working. Very similarly, actually, to the way it then ended up working on set. You know, anytime we would shoot makeup and hair tests, we would have the visual effects and the special effects department off in a corner working on their little miracles. It was almost like a whole other film was being made in parallel. And I don’t want to talk to you specifically about the way they did it because that, you know, you don’t want to know how the trick works. But it worked seamlessly and those were some of the first dailies that we looked at, and it was absolutely incredible. It was just magic watching this stuff that hadn’t been touched by a computer; it literally had just been shot in a corner on the stage. It was really miraculous.

CN: In very experimental conditions. Which, from Emma’s point of view, from a production point of view, it’s really tough to get any kind of experimentation into the framework of a big budget Hollywood film. It’s a strange paradox where the more money you have, the less you can actually just sort of turn up and go, well, what if we just experiment, we shoot a bit of this, or shoot a bit of that. The whole machine, the number of people you’re employing and everything fights that. We were able to find some very good ways because of Andrew. He’s done a couple of films with us—he won an Oscar for Tenet and he did incredible work on Dunkirk. For me, it’s the pinnacle of visual effects because everyone thinks we did everything for real! He’s getting away with all kinds of things that people just aren’t seeing. He knows computer graphics, but he also knows analog methods. He started in the special effects world like Scott Fisher, his partner on these films. He just wanted to be in a closet with his camera and some odd bits and pieces, but he knew that this was going to need to be him. I said, well, we can’t do quite that, but when we were shooting the security hearings, we were in a place with a very large parking lot next to it. So we put up a big tent and we let him kind of move in there and he’d borrow our cameras and give them back as needed, and they’d set all these kind of weird little things up and they’d just be shooting the whole time. It took many, many months of experimentation to get the visual language and the pieces that we needed to put together into the finish film.

When you read the book, what sort of small details gripped you about this character?
CN: Well, the book was written over about a twenty-five year period. The level of research and detail that Kai Bird and Martin Sherwin put into it is unparalleled. I’ve had an interest in Oppenheimer for some time. I included a reference in my last film, Tenet, in dialogue to the moment at which Oppenheimer’s fellow scientists at the Manhattan Project realized they could not completely eliminate the possibility that a chain reaction from the Trinity Test would destroy the world, and yet went ahead and pushed that button. And that’s the most dramatic situational scene that I’d ever heard of. After Tenet, Robert Pattinson gave me book of Oppenheimer’s speeches from the 1950s. Reading those speeches, reading the words of this person trying to wrestle with the consequences, the implications of something that he’d been a part of unleashing into the world was very frightening. And very moving. When I came to read American Prometheus there’s a moment relatively early in the book where you suddenly realize that Los Alamos, this place that’s so important to the history of the world—famous, or infamous, depending on your point of view—it was just a place that he and his brother liked to go camping. It was a place they would go pitch a tent and ride their horses around. And he thought it was one of the most beautiful places in the world. Realizing the relationship between the personal and the global, the massive significance of that, to me, that was uniquely traumatic. It hit me in a very profound way. And I think from that point onwards in reading the book, I knew that it was something I just had to do.

That makes me think of the moment in the film where he’s asked, what should we do with Los Alamos? And he’s like, “give it back to Indians.” It feels like that’s actually a thing he thinks could happen.  
CN:  Yeah, I mean the conversation with Truman is as best I can tell, pretty accurate to the actual sort of… I don’t know what you call a meeting of the minds that isn’t really a meeting! It’s a scene about misunderstandings and Oppenheimer has the type of naivete at times in this story that only really brilliant people seem to possess. You know, the intellect allowing him to sort of miss some really basic things. When he said that Truman, it wasn’t as a provocation. I was very happy with the way Cillian plays the scene with Gary. I was very happy with it because it’s not a provocation. I think this speaks to that earlier answer about the personal; he feels that Los Alamos is his place and that now that he’s done with it, they’ll give it back to him, give it back to the Indians, give it back to nature or whatever. He sees that the things will go back to the way they were. And there’s something very heartbreaking about that because this is a film about consequences. Unintended consequences, particularly.