Category: GRAVITY

The LED Light Box

Early on it became clear that moving the actors through space on wires would not create the desired realism of weightlessness, and obviously they could not be whipped about and tumbled in ways that the film ultimately achieved. The actors would have to be relatively static, with the illusion of movement created through other means. One of the main challenges was to have the lighting on their stationery faces support that illusion. And it would have to be done perfectly in order to achieve the photorealistic depiction of space that the filmmakers were after.

Usually in watching a film heavily dependent on CGI, one notices elements that have been assembled into a single composition but don’t quite match each other. A matte painting that isn’t lit from precisely the same angle as all the other components stands out from the rest (as, it has to be admitted, happens in the best of CGI scenes, including those in The Lord of the Rings). The problem was solved for Gravity using the LED Light Box, a device frequently mentioned in the press coverage of the film but seldom explained. (See image at the top.) The concept is truly revolutionary, although I am not sure to what extent it would work for other films that did not present such peculiar challenges.

In American Cinematographer‘s article on Gravity, “Facing the Void,” cinematographer Emmanuel Lubezki explains why consistency of lighting is crucial and how he came up with his solution:

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 [special effects head Tim] 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 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.

This ingenious approach largely did away with traditional three-point lighting in the exteriors. As Lubezki explains in the AC article,

When you put a gel on a 20K or an HMI [Hydrargyrum medium-arc iodide], you’re working with one tone, one color. Because they 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.

The crucial point here is that the lighting was being created by playing the previs animation of the earth, space, the moon, and the large reflecting objects like the space shuttle on the sides of this 20′ by 10′ box. In other words, the moving images from the nearly finished special effects were used to light the faces of the actors, and those faces were later joined to those very same special effects, in a more polished form, to create the final images.

Lubezki gives an excellent description of the Box in his interview with Bryan Abrams, a series of responses which is worth quoting at length. Note that Lubezki refers to the Box as an LED monitor–essentially a giant television screen turned inside out and surrounding the actor:

Can you touch upon some of the pieces of technology and equipment that were created to make Gravity possible?

To make this movie we used many different methodologies. For one of them, we invented this LED box that you’ve probably read about, which is basically this very large LED monitor that is folded into a cube. So all the information and images that you input into this monitor lights the actors, and you can input all of the scenes that were pre-visualized to create the movie—all the environments that we had created—and you can input them into this large cube so space itself is moving around the actors.

So it’s not Sandra Bullock spinning around like crazy, it’s your cameras.

Yes, instead of having Sandra turning in 360s and hanging from cables, what’s happening is she’s standing in the middle of this cube and the environment and the lighting is moving around her. The lighting on the movie is very complex—it’s changing all the time from day to night, all the color temperatures are changing and the contrast is changing. There were a lot of subtleties that you can capture with the box, subtleties that make the integration of the virtual cinematography and the live-action much better than ever before.

The effects of the LED projections are visible in the changes on Stone’s face in the extended example above. Here’s a brief example of changes on Kowalski’s face in the opening shot:

The harsh light in the right frame above is a real lamp. The LEDs could not produce a local, hard light intense enough to simulate the sun. The team placed “a small dolly and jib arm alongside the actors” with a lightweight spotlight. This was moved “according to the progression of the virtual sun.” Such harsh light was necessary because outside the atmosphere there is nothing to filter bright sunlight. Several moments where the actors’ faces and suits are severely overexposed reflect this technique:

The Box also contained a large video monitor, visible to the actor, which displayed the previs animation. Lubezki explains: “This was wonderful in a couple of different ways. The actor sees the environment and how objects are moving in that environment, and at the same time we can see the interaction of that light on the actor. We capture true reflections of the environment in the actor’s eyes, which makes the face sit that much better within the animation.”

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Follow the bouncing axis

For much of the film, there is minimal spatial stability for the characters or for our viewpoint into the diegetic world. There is no ground, so we cannot imagine the camera resting on anything. When outside the space vehicles, the camera moves nearly all the time. In an interview with ICG Magazine, director Alfonso Cuarón was asked, “So with the camera and characters in constant motion and changing perspective, how did you figure up from down?” He replied:

There is no point of departure because there is no up or down; nobody is sitting in a chair to orient your eye. It took the animators three months to learn how to think this way. They have been taught to draw based on horizon and weight, and here we stripped them of both.

Undoubtedly many scenes contain an axis of action running between the characters, but it is not of a traditional kind. Unlike in a classically edited film, in Gravity‘s action scenes in space, the axis is in constant, fleeting motion, and any given center line between two characters must in quick succession run not only left and right but also up and down, diagonally, in almost any direction. Any given screen direction set up by the axis is ephemeral and offers little to help orient us spatially. Eyeline directions mean very little, since there are few cuts to things that the characters have seen offscreen. (True, when characters look offscreen, they establish eyelines, and the camera sometimes pans from Stone or Kowalski to some object they have been looking at. But a pan from a person to an object automatically establishes the spatial relations between them, whether or not the character is looking at the object.)

As a result, the spatial cues used in continuity editing system are not so much eliminated as made irrelevant for long stretches. That system is meant, after all, to guide our understanding of the story space across cuts. There are exceptions, such as a brief shot/reverse-shot exchange: Stone, loosely attached to the International Space Station (ISS) by ropes, pleads with Kowalski not to untether himself from her and float away to die in space, and he insists that it is the only way to allow her to live. When Kowalski and Stone, tethered together, travel toward the ISS, he is always at screen left, she at screen right, with the strap joining them stretched out as a sort of visible axis of action; straight cut-ins to close views of each character, and even at one point Kowalski’s point of view, obey the 180-degree rule and create an almost conventional scene. Actions inside the spacecrafts are more oriented as well. In the ISS Stone moves weightlessly through a series of pods, all the while maintaining screen direction. Similarly, inside the vehicles, especially late in the film when Stone is strapped into seats, she is usually upright, her head oriented toward the top of the frame. Some sustained actions in space also keep her right-side up, as when she removes the bolts holding the parachute cords to the Soyuz landing vehicle.

In part because of such orienting devices, we are seldom seriously confused about where the characters are, or at least not for long. Otherwise we would not be able to comprehend the story action. Still, compared to typical classical films, Gravity conveys little sense of spatial stability. The disorienting simulation of weightlessness for characters and camera dominates the scenes outside the vehicles and creates a style that can truly be called experimental.

Take the brief segment (about 14 seconds) below, from the 13-minute opening shot. Stone has been standing at the end of a large mechanical arm which gets knocked off the space shuttle by a piece of hurtling debris. It spins rapidly, with the camera framing it from long-shot distance. The camera is not entirely static, reframing slightly, but we can see the earth in the background fairly clearly. Stark sunlight comes from offscreen left, and as Stone’s body whips through space, the shadows move accordingly around her, with the back of her body in deep shadow in the first frame and then her front shadowed in the second:

The fact that the light source, the sun, is offscreen left during this spinning segment suggests that the camera and hence our viewpoint are in a stable position. Yet that position is maintained for only a short time. At this point in the shot, the camera is essentially waiting for her to draw near in order for it to execute a change that will govern the penultimate part of the lengthy shot.

That happens when, after she has spun wildly toward and away from us several times, the camera “attaches” to her, so that we are now seeing her in medium shot and spinning with her. Instead of seeing the earth clearly, we see her while the blurred surface of the earth and the blackness of space alternate rapidly. This was the technique that led me, when I first saw the film’s trailers, to compare Gravity to Michael Snow’s Central Region:

Being closer to Stone, we can see more clearly the shadows coming and going; her face is sometimes illuminated brightly by the sun and sometimes in near darkness:

 

The function of the attachment to Stone, apart from allowing us to see her fear and confusion, is to show us that her hands are working to detach her from the arm, as a tilt down reveals:

As she soars off the arm and tumbles into the black depths of space, the camera  leaves its “attachment” to her, and she spins away from it:

Cuarón’s commitment to the long take thus made him rely more than usual on events taking place within the frame–camera movement and figure movement in particular. Yet these movements had to occur in a microgravity environment radically different from the earthbound surroundings of Children of Men and Harry Potter and the Prisoner of Azkaban. This new constraint led to some technological innovations of remarkable originality.

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Arguably Cuarón had constructed nearly the most sparse narrative that can sustain the experimental style and motivate that style enough to hold the attention of a popular audience. Three characters, then two, then one, all with minimal backstories and simple goals.

Most Hollywood films have two parallel plotlines, usually one involving a romance. Here there is only one, and it primarily concerns an immediate situation, a cycle of deadly threats alternating with stages of Ryan’s progress toward safety. On balance, the focus is more on the suspense and terror of the situation than on the characters. Although there is a little mild flirtation between Stone and Kowalski, it’s more to generate humor and defuse the tension than to suggest any real possibility of mutual attraction.

One indication of the film’s minimal characterization is that fact that we never learn the nature of Stone’s experiment. That would be a logical initial goal for her character. Why has she set herself this particular task, which obviously involved not only scientific expertise in  a complex field but also elaborate training to become an astronaut? Where does she work? What might her test achieve? Some reviews have referred to her as a medical expert. As far as I can tell, this is based on one line when she and Kowalski are working together to activate the communications device that is her focus of attention in the opening scene. During the calm before the debris collision, she remarks, “I’m used to a basement lab in a hospital where trays fall to the floor.”  She also says that “It’s designed for hospital use.” That’s it. Normally a Hollywood film would redundantly give us information about her job. Here we don’t even get a sketch of it. And why is a medical experiment attached to the Hubble Space Telescope?

Incidentally, the Hubble is detached from the shuttle just before the debris cluster reaches it. We never learn whether it, too, is destroyed in the disaster. Might it have survived, with Stone’s experiment, perhaps activated during her brief delay before obeying the mission-abort command? Might she return to earth to find her experiment a success, with her initial goal miraculously achieved despite the tragic events in space. So little is the narrative concerned with the experiment as a significant goal that such questions are unlikely to occur to a spectator. They came to me only after three viewings.

Stone’s casual reference to working in a hospital lab typifies the limited sort of backstory we’ll get for the most part. Aside from Stone’s recollections of her daughter’s death and her aimless evenings of driving as her form of mourning, the moments of backstory are mere hints. In the opening we learn that Matt’s wife left him when he was in space on a mission. Might he be so obsessed with the beauties of space travel because he, too, is seeking to escape loneliness? We can’t know, since he treats the mention humorously, as if he has managed to shrug off his wife’s betrayal. Of the third character present on the spacewalk, Shariff, we learn that he has a wife and son, something revealed by a photo only after his death. This knowledge serves less to characterize him than to contrast this cheerful fellow with the wifeless Kowalski and childless, unattached Stone.

Stone’s mention of her home in Lake Zurich, Illinois and of her daughter’s death is the last piece of backstory that we get, and it comes slightly under half an hour into the film, during the calm interlude when she and Kowalski are slowly traveling toward the International Space Station (ISS). After this, I believe the only scrap of information from her past that we get is that Stone’s daughter had worried about a lost red shoe.

This lack of information about the characters is probably what led Foundas to say that the film has “barely” more of a plot than Central Region. In the same piece, he speculates, did the executives at Warner Bros. “wonder if they’d just gambled away $100 million on the most expensive avant-garde art movie ever made?”

Kevin Jagernauth reports on indiewire that the studio pushed for a more conventionally constructed film. Cuarón told him about some of the feedback he got from WB:

But at first, the studio suggested that [the Mission Control] team in Houston should get more face time. “…there were a lot of ideas. People start suggesting other stuff. ‘You need to cut to House and see how the rescue mission goes.’”

And that’s not all. Part of the emotional journey of “Gravity” rests on Stone’s backstory, which includes a daughter she lost, but this is all effectively communicated without breaking the single location concept. However, Cuarón was advised to perhaps include some flashbacks in the film and even more. “A whole thing with … a romantic relationship with the Mission Control Commander, who is in love with her. All that kind of stuff. What else? To finish with a whole rescue helicopter, that would come and rescue her. Stuff like that,” he explained of some of the ideas that were floated his way.

There’s that conventional second romantic plotline, which in the wake of the film’s success seems such a ludicrous suggestion. The studio’s attitude demonstrates how very much Cuarón was able to get away with and how much of a struggle it must have been. Audience and critical enthusiasm suggests that he and his team managed to include just enough classical storytelling to make spectators identify with the characters even while knowing very little about them.

Why would a film need to establish psychological depth for characters when most of what they’re going to be doing is struggling frantically for their lives, cast adrift in space and bombarded by hurtling space debris? They must summon what skills and psychological strength they have and get on with it. Thoughtful conversations and subtle complexities are irrelevant for the most part. We need to care about these people to be engaged by the film, but that is part of the point of having Sandra Bullock and George Clooney as the leads, playing to the likeable personal qualities that we already associate with these stars.

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Iris in

The Light Box technology is astonishing enough, but within its confined space there also had to be a way to photograph the actors. In Lubezki’s interview with Bryan Abrams, he explains:

So we built the box, but that wasn’t it.  To be able to shoot inside the box, we had to build a special rig that holds the camera and moves with motion control. So we had people build a very narrow, lightweight but sturdy rig to control the camera. If you imagine the big box of LEDs, it has a gap that is almost a foot and a half or two feet wide, and the camera has to go into the box and make all these moves to make the audience believe that Sandra is turning and turning, but it’s really the camera and the environment in the box that is moving. So we built the box, the rig, and then used a company called Bot & Dolly. These guys are from San Francisco, and they use robots from the automotive industry.  They redid all the software for us, so we were able to use these robots to move the cameras and the lights around the actors. It was just a big ballet of gadgets and new technology for the film.

Bot & Dolly is a San Francisco company specializing in robots for the automobile industry. It built or perhaps modified an elaborate rolling, multiply-jointed camera mount called Iris especially for Gravity. It has been used in other features and in ads since then. (See image at the bottom.) An impressive demo film shows the Iris gracefully writhing about, quickly pointing the camera in many directions. (The camera in the film is a Red, though Gravity used an Alexa.) According to ICG Magazine, “The firm devised a Maya-based series of commands that allowed Framestore animators to direct the robots in ways that matched previs action in precise detail.” (Maya is the industry standard computer animation program.)

Typically this camera was inserted through an opening in the Light Box and swooped around the actor, who stood in a gyroscopic basket, seen in the production photo below. The photo shows one side of the Box open, though this would not be the case during shooting:

The combination of the Light Box and Iris made it possible to blend the special-effects shots and the live-action photography of the actors so smoothly that there is no “uncanny valley” effect, no sense of an obvious matte painting stuck into the middle of an image. The shots in Gravity are all photorealistic to a degree that is rare, if not unique, in recent effects-heavy films.

Iris brings us back to the comparison with Central Region. Snow built a special camera mount (below) designed to allow his images to rotate freely in almost any direction. During the three-hour film the camera never repeated any of its trajectories. Some images were close views of the pebbles on the ground; others were upside views of the bleak Canadian mountains in the distance. A nighttime segment was completely black except when the moon occasionally swept through the frame. The one area that the camera didn’t survey was the camera support itself, the “central region” of the title.

 

The vital difference between Snow’s machine and Iris is that the new system has no fixed anchor. Not only does it slide on a track, but everything it photographs can be digitally altered to erase any traces of the machine. It moves with entire freedom through a constructed space that has no central region, no fixed point around which everything else revolves.

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Puppeteers and eyes

Gravity‘s utterly spherical space, beyond anything we normally find in commercial cinema, placed unusual demands not only on camera movement but also upon the actors’ blocking and performances. Our first entry on Gravity begins with a quotation from Sandra Bullock, which included the statement, “No character was like Stone, no film set was ever like these sets, not one member of this crew had ever done this before.” That may seem an exaggeration until one grasps how Bullock and Cuarón’s team built her character.

We all know from infotainment coverage that Bullock was isolated in the Light Box through entire days and that it was a trying experience. What doesn’t come through in such accounts is that she was often enclosed in the gyroscopic basket, visible in the photo of the Iris rig and Light Box above, as well as in the same setup visible behind Cuarón in this photo:

That was only the start of it. Anne Thompson’s interview with Cuarón and producer David Heyman reveals some of the details of blocking a character who is unrestricted by gravity:

AC: The physical aspect, not anybody can do what she did. On the one hand the physical discipline she went through to make this film, the training and the workouts. She also has an amazing capability for abstraction. Those emotional performances, it was as if they were an exercise in abstraction, like she was bonded to very precise cues. And physically that was very difficult: she trained and practiced like crazy, together with the stunt people and special effects. And the puppeteers from “War Horse” were helping her, supporting a leg or an arm, all the floating elements, they were creating approaching objects toward her in perfect timing. Then after she practiced so much her whole concern was only about emotions and performance.

Imagine a ballet dancer with really strict physical discipline in terms of what a body has to do, positions and precise choreography, who goes through months of training for one choreography so when they are performing they have expressiveness and emotion.

What was the most challenging scene to realize?

David Heyman: When Sandy comes into the ISS for the first time. She takes off her suit, then goes into fetal position, all in one shot. It was the most difficult. All the objects, getting the suit off, and into fetal position in such a way that it felt effortless, not as it was–she was sitting on a bicycle with one leg tied down leaning back in a 12-wire rig, with puppeteers. One of the things you forget about Sandy’s performance, which seems so truthful, is all the effort and physical exertion that went into making it, the precision of the technical aspects. She had to move her hands at a third of speed — zero G –while talking. Each shot connects with the next at very precise points where her head began and end and begin and end. She’s on a bicycle stringing uncomfortable with people moving around on 12 wires, through it all, with no gravity. Physically the body must not show the tension, so it looks effortless. What I loved about it is the performance behind the visor shines through, her eyes. You can’t slouch your shoulders to show sadness or weight, it’s just the eyes.

Bullock did all this with four 10′ by 20′ walls of LEDs projecting moving images of the earth and of exploding space stations around her. I think it is safe to say that this was a unique kind of performance.

 

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