The American Society of Cinematographers

Loyalty • Progress • Artistry
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Return to Table of Contents November 2013 Return to Table of Contents
Presidents Desk
Gravity
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Gravity Workflow
Gravity Q&A Subscriber Only
ASC Close-Up

“The Alexa allowed me to shoot ASA 800 native, and it still looked great if I pushed it to 1,200, which made it possible to use the LED sources,” Lubezki notes. Also, the Alexa’s latitude enabled him to “deal with the overexposure of a harsh, hard sunlight. We didn’t want to lose any of that detail.”

To shoot the actors in the LED Box, the crew put an Alexa on a modified Mo-Sys remote head, which in turn attached to a large, motion-controlled robot arm that could be moved around the actor in a preprogrammed trajectory. This system enabled the filmmakers to take advantage of the relative motion between objects in space. Because there is no “up” or “down” in zero gravity, shooting a moving object with a static camera is visually equivalent to shooting a static object with a moving camera, and the filmmakers elected to make the camera perform most of the motion.

The robot arm was originally designed to assemble cars, according to Webber. He explains that Warner Bros. executive Chris DeFaria read about a San Francisco design-and-engineering studio, Bot & Dolly, which had used the arms to move a camera. Webber adds that the production worked with Bot & Dolly to add increased flexibility to the system, including the ability to adjust the speed of the preprogrammed moves so they could be adapted to the actors’ performances. To create even more options, they added a special remote head that was manned by camera operator Peter Taylor. Based on a Mo-Sys head, this remote unit was adapted to make it smaller and lighter, partly so that it would block less light. It could be operated live or set to play preprogrammed moves driven by the previs.

Gaffer John “Biggles” Higgins, who also worked with Lubezki on Children of Men, marvels that he has “never seen anything like the set of Gravity.” Apart from the LED Box, he notes, there were also other, slightly more traditional setups. For interiors of the space capsule as it hurtles to Earth, for instance, the filmmakers used an Alpha 4K HMI without its lens to simulate the sun, moving the source around the stationary capsule with a crane and a remote head. Higgins says they selected the Alpha because “it is the only head that can be operated shooting straight down.” He adds that Lubezki would provide ambient light by punching powerful tungsten 20Ks through 20'x20' frames, using two layers of diffusion, Half and Full Grid Cloth, as well as green and blue gels, to simulate sunlight. “These diffusions were mainly used on the real capsules,” explains Higgins. “The green and blue filters were stitched to the back of the closest diffusion, the 20-by-20 Full Grid.”

As the production footage of the actors was integrated into the CG imagery, some modifications were made to the virtual elements to reflect the actors’ performances or changes in the lighting on their faces. Lubezki adds, “I suggested to Tim that we add lens flares and chromatic aberrations in the CG so it would look as if the [entire] image had been captured with a camera.”

Once Framestore finished the rendering process to the filmmakers’ satisfaction, Lubezki and Cuarón supervised the final grade at Technicolor with supervising digital colorist Steven J. Scott. Scott, an ASC associate member, was struck by the duo’s passion for detail. He recalls, “Chivo and Alfonso would start with something that would look brilliant to 99 percent of the audience, but they’d say, ‘There’s a little too much cyan in the top of his backpack as we pass by.’ So, we’d do a rotoscope animation to isolate that area, then fade the cyan adjustment in for the brief moment it was needed, and fade it out as we went by. When you work with Chivo for weeks and weeks, you see that all those seemingly minor adjustments make a huge difference. The cumulative effect is inevitably a revelation.”

In turn, Cuarón enthuses that Scott “understands and completely respects and honors Chivo’s vision, but at the same time, he is also an artist with amazing technical resources. Steve has a great eye, and he understands what naturalism is all about.”

Looking back at Lubezki’s work on Gravity, Webber offers, “I’m not aware of any other prelight done anywhere near this level. I think this was a first. It was great working with Chivo, who is not only an incredible talent, but also very willing to use this new technology and embrace lighting within this new environment. Even though very little of the film is physically lit in the way Chivo would normally do it, his touch is all over everything.”

Cuarón and Lubezki share an appreciation for “the genius” that Webber brought to Gravity. They also note that cinematographer Michael Seresin, BSC filled in as director of photography when Lubezki had to leave the set for personal reasons. “Michael came into a very complicated set and adapted to it wonderfully,” Cuarón says.

Reflecting on his relationship with Cuarón, Lubezki offers, “The truth is that ever since I met him, Alfonso has always been one of my most important teachers. I worked with him in film school as his gaffer when he was the cinematographer, as his boom man when he was sound mixing, as his second AC when he was a first AC, and finally as his cinematographer when he became a director. I know him well. He’s my teacher and also one of my favorite filmmakers. I’m very lucky to work with him.”

“Chivo is my co-filmmaker,” says Cuarón. “He is not just doing what most people think of as the cinematographer’s job. On Gravity he was everywhere, collaborating every single step of the way.”


TECHNICAL SPECIFICATIONS

2.40:1

Digital capture and 65mm

Arri Alexa Classic, 765

Arri Master Prime, Panavision Primo

Kodak Vision3 500T 5219

Digital Intermediate

Stereoscopic Conversion


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