The 33 retells the story of the Chilean miners who were trapped in a gold and copper mine for 69 days in 2010. Half the film was shot miles underground in a stand-in mine in Columbia. 

Darkness was an integral part of the story, and it also defined the environment in which the filmmakers worked, seeping into their consciousness. The other half of the story unfolds aboveground, in Chile’s stunning Atacama desert, one of the driest places on earth, where the blinding sunlight and blowing sand dealt the filmmakers other challenges.

With these extremes in mind, the director, who is Varese’s wife, Patricia Riggen, warned him early on not to squander the project’s powerful visual potential.

“Our first conversations after reading the script were related to the realistic sense that she wanted to imprint on this story,” says Varese. “I’m a firm believer that you have to start by anchoring yourself to some kind of reality, even in science fiction. That way, you can maintain the suspension of disbelief. I usually start by thinking of a painter, and in this case, the painter who came to mind was Caravaggio, because he has this chiaroscuro, with very dark and very bright areas in the frame.”

Varese also took inspiration from a series of photographs of Afghani coal miners taken by master stills photographer Steve McCurry (www.stevemccurry.com).

The cast included Juliette Binoche and Antonio Banderas. The decision to shoot in a real mine added authenticity but also complexity in terms of logistics, lighting, safety and other concerns. “But the way Patricia wanted to shoot it, there would never have been a stage big enough or a budget generous enough to contain it,” says Varese.

Varese and Riggen had made three previous feature films together, and they share long service in documentary film, Varese having worked in war zones through the 1980s. That experience informed their approach to the imagery as well, with plenty of handheld camera work. Varese operated the A camera himself.

Gaffer David Lee helped Varese plan and execute the lighting. In the mine, that essentially meant mimicking flashlights, industrial lamps, and an occasional candle, until in the story all the batteries die and the men are starving and desperately thirsty. Often the miners lit each other with headlamps that were slightly warm in colour. Varese shot on ARRI ALEXAs, using ARRIRAW recorded to Codex Capture Drives. The lenses were Ultra Primes and Angenieux Optimo zooms. Underground, the cameras were pushed to EI 1280 or 1600, sometimes under-exposing as much as five stops. Rental equipment was provided for the most part by Equipment Film and Design (EFD)’s Columbia branch.

The filmmakers spent about six weeks in each locale. Digital Imaging Technician Carmen Del Toro says that The 33 was “a life-changing project.”

“The images just give you the feeling that you are right there with them, watching everything happen,” she says. “Not only is the mine falling apart, but they begin to fall apart as humans.” For the first two weeks of the shoot, Del Toro sent Varese’s colourist, Stefan Sonnenfeld, ARRIRAW files so he could confirm that the 1600 rating was not resulting in unacceptable grain or noise. On the set, she used LiveGrade Pro to generate CDLs from the live feed signal. She would convert that to Rec709, which was then sent to video assist, where Sony BVM series OLED monitors, calibrated by Del Toro, presented the image to Riggen and her team. Each card gave about 40 minutes of record time. Off-load was away from the set, because computers and hard drives don’t take well to conditions in a salt mine. Corrosion was a major issue. And in the dry Atacama desert, Del Toro had to continually replace and clean the calcification off the connections.

Del Toro’s equipment included a Mac Pro tower with 96 gigs of RAM running Resolve, connected to a 48-terabyte RAID and a Codex Dual Dock.

“I thought it was important to have the negative verified by the same company that makes the Capture Drives, and designed the whole workflow, which is Codex,” she says. “So we used the Codex VFS to offload the material to the two rigs we had on the set. One copy would go to a shuttle drive and the other to the 48-terabyte RAID.”

Because CDLs weren’t being generated at the time of recording, Del Toro would generate CDLs for each scene and camera. The data manager would add the CDL info to the ARRIRAW files, which were then downloaded and verified inside Resolve. Each night, that Resolve project was shared with the lab, a company called Bling which provided dailies and did the final handoff to DI.

The brutal conditions tested Del Toro’s skills. In the blazing sun, she followed Varese into a crowd with 120 metres of cable, because the antennas were overheating and dropping out. She would open her Mac tower to find the green motherboard completely obscured by fine sand. She never lost a computer though. At one point, a RAID went down, but the material was backed up in three different places.

“Because we were shooting ALEXA XTs with Codex inside, we had one computer working on the camera instead of two,” she says. “The cameras were left in the mine overnight, covered, and they survived. We never had a camera issue.

“In the mine, you get grey hair quicker,” Del Toro says. “But I’m very confident with the ALEXA cameras and the Codex system. I just knew that the things that might break were things we could easily replace. Checco knew that he couldn’t bring the reality with those blacks, and that high contrast. It was a big challenge to do it well, to have it feel realistic, and yet give the audience the ability to see what’s going on.” Looking back on the experience, Varese says, “We did crazy things. There was no light. And everyone says, ‘Oh my goodness, it looks terrific.’ And besides that, it’s a fantastic movie.”

The 33 will debut in Chile in August, and opens in the United States in November 2015. It is in competition at Camerimage 2015.