Brow Beat

How James Wan Sent Aquaman Underwater

Aquaman and Mera in a ship underwater.
Blub blub blub.
Warner Bros.

If the original Richard Donner Superman film promised that you’d believe a man can fly, James Wan’s Aquaman is dedicated to making you believe a man can swim really fast. The film follows the trials and tribulations of Jason Momoa’s Arthur Curry, a half-Atlantean hunk who spends much of the movie interacting with other children of Atlantis, all of whom primarily conduct their business underwater. The film thus lives or dies based on whether it can make the aquatic sequences seem natural and smooth. This was no easy task, as it turns out.

“The underwater world encompasses around two-thirds of this particular film,” Wan tells Vulture. “So we had to get it right technically so that it would be at least somewhat believable and so that it would look cool and so that you would actually be able to buy something that makes up such a huge chunk of the movie. If we didn’t get that right, it was going to be a problem in a big, big way.” To make matters more difficult, Wan—best known for his work on intimate horror pictures like Saw and The Conjuring—was an amateur with this sort of thing. As he readily admits, “Aquaman is really my first visual-effects-heavy movie.”

To begin, well before principal photography, Wan and his team just observed how things look under the sea. “We started by looking at humans swimming underwater,” he recalls. “We would put wigs and stunt doubles and props underwater just to see what they would look like.” Data thus accumulated, they got to work on re-creating that imagery on dry land, which is where the film was mostly shot.

“We had to make these rigs that would allow for our actors and stunt doubles to look like they were swimming,” Wan says. “It was a totally laborious process that involved putting these actors through some really uncomfortable situations. Not only are they having to act while they’re on a wire rig, almost all of them were having to do it while wearing these really outlandish costumes. And on top of that, they had to look like they were moving elegantly, you know? Moving around in the water is this very graceful and elegant thing for these characters. It’s a really uncomfortable thing to do as an actor.”

Because the actors were above the depths, there was all kinds of CGI mishegoss required to make their accoutrements look like they were swaying in the currents. “It was months and months and months of trying to develop the physics, trying to get the CGI to look believable, the movements of things like capes and costumes and hair,” Wan recalls—emphasis on hair. “And in the case of Jason Momoa, there wasn’t just the hair on his head—we had to figure out how to make his beard look like it was underwater, as well. And when you’re doing that, you’re actually physically affecting the actor’s face and how their performance comes across so that just took months and months.”

The hair-replication process was agonizing. “Sometimes, the effects house would come back with something that got the physics perfectly but didn’t make the actors look cool,” Wan says. “Other times, it just wouldn’t look right, it had to be redone. We’d have to go back to the drawing board and re-render every single strand of hair. We’re talking, like, hours to render one shot that could only maybe be a couple of seconds long.”

There was also the matter of not falling into the trap of turning the Atlanteans into Superman. “I learned very early on that actors could look like they were flying rather than floating in water, so that was something we had to be mindful of as well,” says Wan. “We had to figure out ways to remind the audience that they were underwater, which we did by developing these simple but effective visual cues, like adding bits of floating particulate—something that we’ve all seen in swimming pools before. We added in little bits of debris, just as a way to remind people that, Right, yeah, this is all happening in water. And, of course, bubbles and stuff.”

There was actually an entire approach to the swimming effects that Wan used, then discarded at great expense during the production process. “We think about people swimming, and there’s this very slow-motion quality to it,” Wan muses. “I shot a lot of the movie like that before I ultimately realized that that was just not correct for the look of the film. Atlanteans would not be moving in slow motion, despite being underwater. Through the course of research and development and principal photography, we realized it was just not the right look. The whole movie would have been just way too slow.”

The finished product is definitely not slow—everyone zips around beneath the waves like they have bubbly Saturn V rockets on their feet. The whole movie is something of a visual marvel, and Wan hopes to take the hard-won lessons forward as he swims through Hollywood. “Now I know how long these things take, the processes involved,” he says. “I learned even just giving notes on a shot can have an unraveling effect to all the stuff that had been done before. It can have a kind of snowball effect. That’s something that I’m definitely going to take with me down the line.”

See also: See Aquaman for Its Trippy Undersea Visuals and You Won’t Be Disappointed