When editor Pietro Scalia arrived in London two weeks before principal photography began on “Prometheus,” he needed to discuss workflow plan with the camera department. He also needed to calibrate the monitors so the same high-definition 3D images that director Ridley Scott and cinematographer Dariusz Wolksi captured with the new Red Epic camera system would be re-created accurately in the dailies and the editing suite. But what he really wanted to do was to step aboard the bridge of the titular spacecraft and production designer Arthur Max’s other giant sets that were overflowing from the cavernous soundstages at Pinewood Studios.

“It’s good to feel the geography of it,” Scalia says. “You can’t duplicate that volume and space just by all the mathematics of CGI, and I felt that I wanted to use that as much as possible.”

To further that goal, Scalia decided he would view the film in 3D as he cut it.

“I notice very early on that the space (created by 3D) itself is another element, just like color or movement,” Scalia says. And cutting in 3D, “you could see that a certain movement would feel more musical or graceful and the way that certain things were lit felt better, and that influenced my choices in takes.”

“Prometheus” is Scalia’s first film in 3D, but his eighth for director Ridley Scott, stretching back to 1997’s “G.I. Jane.”

Scalia says, like any good collaborative relationship, theirs is based on trust and compatibility.

“A lot of times, the trust is about choosing takes and performances, building the scenes, and the creative freedom that Ridley gives me, I value a lot,” says Scalia, who has won Oscars for Scott’s “Black Hawk Down” (2001) and Oliver Stone’s “JFK” (1991).

Scalia spent nearly six months in London working on “Prometheus,” four months during shooting, cutting sequences as Scott shot them, then another eight weeks with Scott honing a director’s cut. The initial assembly edit was done a week or so after principal photography wrapped.

“Ridley likes to work fast,” Scalia says.

Scalia also had the typical editor’s task of picking out a temp score for his rough cut, some of which — including his use of Chopin’s Prelude No. 15 in D Flat Major for a scene in which the android David (Michael Fassbender) walks the ship alone — made it into the final cut. He also spent 2 1/2 days on set with a splinter unit shooting insert shots.

But the biggest extra weight in his workload was the exponentially larger personnel and data management issues that came with shooting in 3D.

Scott shot with four 3D rigs, each of which had a separate camera for each eye, and “every single shot would go through this process of alignment and color correction,” Scalia says. “It was the biggest crew I’ve had in terms of assistants, stereographers, visual effects compositors and visual effects editors. You’re dealing with a dozen different vendors and a huge number of zeroes and ones.”

Scalia found that 3D also affected the rhythm of his editing.

“The eye takes a little more time to settle in space,” Scalia says, so fast cutting can be “hurtful and distracting. However, certain action scenes needed to have a faster rhythm, so we decided we can do it faster, but later on in the digital intermediate we’d have to reduce the depth of the 3D.”

Scalia believes that the extra work he put into the edit will save audiences members from the dreaded 3D headache.

“I think you get a headache if your eye has to shift very drastically (depth-wise) from cut to cut,” Scalia says. “If the 3D was wrong, I would send it back and say, ‘We need to fix this.’ ”

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