The American Society of Cinematographers

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Return to Table of Contents November 2013 Return to Table of Contents
Presidents Desk
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Gravity Workflow
Gravity Q&A Subscriber Only
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Webber adds that the camera moves for a few of the shots were motion-captured with a small rig that the filmmakers moved in a real space to create moves within the CG environment. “We wanted the camerawork to have a natural feel,” says Webber. “So, rather than have everything key-frame-animated, we did some virtual camerawork in a small motion-capture studio. Alfonso, Chivo and I could take the rig and just wander around, controlling the camera and framing up shots, and we later tweaked it a bit to make it feel more like zero gravity.”

Lubezki believes that the long take (plano sequencia in Spanish) brings the audience into the movie in a striking way. “The main thing about the plano sequencia is that it is immersive. To me, it feels more real, more intimate and more immediate. The fewer the cuts, the more you are with [the characters]; it’s as if you’re feeling what they’re going through in real time. This is something Alfonso and I discovered on Y Tu Mamá También and Children of Men.”

Cuarón notes that whenever he was tempted “to do a camera move just because it was cool, Chivo would not allow that to happen.” He cites the example of the opening take, which ends with Stone drifting away toward open space. “When we were doing the previs, as she started floating away, I said, ‘We don’t need to cut. We can keep following her in the same shot, so the first two shots would be just one shot.’ But Chivo said, ‘I think when she’s floating away is the perfect moment to cut. If this were the chapter of a book, this would be the last phrase of the chapter.’ And he was right. Otherwise, we would have started calling attention to the long take and creating an expectation that that’s what the film was about. But that’s not what it’s about. The camerawork serves … I don’t want to say it serves the story, because I have my problems with that. For me, the story is like the cinematography, the sound, the acting and the color. They are tools for cinema, and what you have to serve is cinema, not story.”

In another memorable camera move, the frame starts on Stone’s point of view, looking through her helmet and its reflections, and then goes through the headpiece glass, ending on an external wide shot. Cuarón explains, “There’s a purpose there. At the beginning of the film, we wanted to present a kind of objective reality, where we just see a routine mission. After disaster strikes, we continue to follow Stone objectively until we grab a POV and go to a subjective experience. The interesting thing is that from the moment it comes out of that helmet, the camera is no longer either objective or subjective. It becomes an immersive experience, as if the viewer is right next to her.”

After the creation of the previs animation with virtual camera moves, the next stage was the prelight, when Lubezki defined the CG lighting in concert with the team at Framestore. “Working with a lot of digital gaffers, I was able to design the lighting for the entire film,” says Lubezki, recalling that there were about a dozen people working on the lighting of different scenes.

Paul Beilby, a CG lighting supervisor, notes that the prelight with Lubezki was designed for speed and was much more involved than the process had been on any previous Framestore project. “We worked directly with Chivo,” he says. “We used rough interpretations of very primitive objects because he is used to very quick feedback in terms of what the light’s going to look like.”

Senior visual-effects producer Charles Howell explains that Gravity’s lengthy shots required the filmmakers to make many decisions early in the process. “I think there were only about 200 cuts in the previs animation, [whereas] an average film has about 2,000 cuts. Because these shots had to be mapped out from day one, many of the lengthy shots didn’t really change in the three years of shot production. Because we did a virtual prelight of the entire film with Chivo, the whole film was essentially locked before we even started shooting.”

Lubezki emphasizes that Gravity’s blending of real faces with virtual environments posed a tremendous challenge. “The biggest conundrum in trying to integrate live action with animation has always been the lighting,” he says. “The actors are often lit differently than the animation, and if the lighting is not right, the composite doesn’t work. It can look eerie and take you to a place animators call ‘the uncanny valley,’ that place where everything is very close to real, but your subconscious knows something is wrong. That takes you out of the movie. The only way to avoid the uncanny valley was to use a naturalistic light on the faces, and to find a way to match the light between the faces and surroundings as closely as possible.”

This challenge led Lubezki to imagine a unique lighting space that was ultimately dubbed “the LED Box.” He recalls, “It was like a revelation. I had the idea to build a set out of LED panels and to light the actors’ faces inside it with the previs animation.” Lubezki conducted extensive LED tests and then turned to Webber and his team to build the 20' cube and generate footage of the virtual environments, as seen from the actor’s viewpoint, to display inside it. While constructing the LED Box, the crew also solved problems involving LED flicker and color inconsistencies.

Inside the LED Box, the CG environment played across the walls and ceiling, simulating the bounce light from Earth on the faces of Clooney or Bullock, and providing the actors with visual references as they pretended to float through space. This elegant solution enabled the real faces to be lit by the very environments into which they would be inserted, ensuring a match between the real and virtual elements in the frame.

For Lubezki, the complexity of the lighting from the Earth source was also essential, giving nuanced realism to the light on the faces. “When you put a gel on a 20K or an HMI, you’re working with one tone, one color. Because the LEDs were showing our animation, we were projecting light onto the actors’ faces that could have darkness on one side, light on another, a hot spot in the middle and different colors. It was always complex, and that was the reason to have the Box.”

Lubezki also needed to add a moving hard light that would serve as a sun source and match the CG sun in the prelit animation. To achieve this, he had his crew place a small dolly and jib arm alongside the actors, with a lightweight Robin 600E Spot on a remote head. Key grip Pat Garrett moved the dolly and jib during each take according to the progression of the virtual sun, and camera operator Nick Paige controlled the head to keep the light trained on the actor.

Lubezki used a technique similar to the LED Box for a live-action scene in which a fire breaks out in the space capsule. To light Bullock, the cinematographer diffused an LED panel that displayed the CG fire, ensuring a perfect match of the color and rhythm of the firelight source and how it played on Bullock’s face in the final scene.

Lubezki shot most of the live-action material in the film with Arri Alexa Classics and wide Arri Master Prime lenses, recording in the ArriRaw format to Codex recorders; the package was supplied by Arri Media in London. (Panavision London provided a Primo Close Focus lens that was used for a single shot.) He filmed a scene set on Earth on 65mm, using an Arri 765 and Kodak Vision3 500T 5219, to provide a visual contrast to the rest of the picture.


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