The National Geographic movie 'Endurance' brings Sir Ernest Shackleton’s Antarctic expedition to life using colorized footage and cutting edge techniques, blending historical and modern narratives together into a seamless story.
Considered the world’s first documentary feature, South was a record of Sir Ernest Shackleton’s 1914 to 1916 Endurance expedition to Antarctica, during which the ship was crushed by ice, stranding the crew. Over a hundred years after the ship was lost beneath the ice and Shackleton had led his crew to safety in an epic feat of survival, a sponsored expedition organised by the Falklands Maritime Heritage Trust attempted to find and film the wreck.
They did so, with historian and presenter Dan Snow on board the South African icebreaker Agulhas II, to publicise the event. That 2022 expedition and the original heroic failure are the subject of new film Endurance (available on Disney+) which not only colourises the original footage but uses AI to bring Shackelton’s voice to back to life.
It’s directed by Elizabeth Chai Vasarhelyi and Jimmy Chin, Oscar-winning filmmakers of Free Solo and Emmy-winning documentary The Rescue, about the against-all-odds rescue of 12 boys and their coach from inside a flooded cave in northern Thailand.
Bob Eisenhardt edited both of those docs and is also a producer on Endurance. The production had access to the 4K restoration of South from the BFI that was released in 2019.
“We wanted to make sure we could tell the Shackleton story and give it weight in the film because it's just one of the greatest survival stories there is,” he says.
There was around 40 minutes of remastered footage but in the process of accessing it from the BFI they discovered another unrestored reel of 10 minutes.
“The Hurley footage is spectacular. It looks like it was shot yesterday, but unfortunately when they abandoned the ship, they abandoned the cameras. So we had half the story we could tell through Hurley and the other half of the adventure, the fight for survival, was dramatically reconstructed.”
They filmed original recreations in California and Iceland, on glaciers and recreated boats in actual ice and freezing temperatures.
The original footage from South was donated to the BFI in the 1950s and the archive began to restore it back in 1994. There was no one complete original negative source for South. Overall, 99 different copies of film relating to Shackleton in the Antarctic, varying in length and age, were examined to piece together a restored version as authentically as possible.
The restoration used original camera neg from the expedition, prints from the sound reissue, nitrate release prints from the EYE Filmmuseum in the Netherlands with colour tinting, as well as 18 photographic glass slides.
The original photochemical techniques for colour tinting and toning were also recreated by the conservation team. This was completed in 1998, then digitally remastered for the film’s centenary, with renewed inter-title cards and a newly commissioned score by Neil Brand, in 2019.
“For the longest time I was just looking at the footage as a 1.3:3 image in black and white and it felt like we should keep that as an artefact. But when compared to the other material it also began to look like you were looking through a little porthole,” says Eisenhardt.
“The first decision was to blow it up a little to 1.6:6 and as soon as we did that we could see what was happening in the images much better. Then we talked about how we could the whole story more immediate. The big problem with history is how you make it resonate for audiences. That’s when the idea of trying colour came in.”
Hurley had in fact tinted his original film with sequences in blue, green and amber. It looks somewhat crude today but was cutting edge for its time.
However, their agreement with the BFI explicitly forbade any colourisation. “We couldn’t touch the footage,” says Eisenhardt. “So we ran an experiment. We had our partners at BigStar use AI to colour a sample of the image and it looked amazing.
“I’d been living with the black and white footage for six months and suddenly the images jumped off the screen. You can see that they’re eating peas for dinner and there was Shackleton in the middle of the scenes which you never really noticed before.”
They still had to get permission from the BFI. “They were adamant against colouring it. The archivists were very afraid of the Peter Jackson effect - that we would be creating something completely new. We wanted to stay away from that too, but they also insisted that the colours be accurate. That was very complicated but we solved it by devising a colour wash. When the BFI saw the colour wash samples they allowed us to do it. The fact that we were able to use colour gave the story so much more life.”
Like Jackson’s work on the Imperial War Museum’s archive to make They Shall Not Grow Old however, they did use AI to interpolate or create new frames to enable the film to be presented at 24 fps.
“We did a lot of research around the colour of clothing, the colour of ships and other textiles and materials of the voyage,” explains Josh Norton, Founder, and creative director at New York-based creative agency BigStar (styled BGSTR) which previously worked on Free Solo. “We standardised those colours and spent weeks digital crafting each frame with some advanced software and AI to get to our final result.”
They determined that AI was not of a high enough fidelity to do all the work. “You can do an okay job quickly using straight out of the box AI approaches and effects - and there's a lot of different packages out there that do that,” Norton says, “but the amount of control that we needed to stay true to the material and to give a consistent result needed a large amount of manual craft work.
“This includes tracking clothing, and having just the right Burberry green for all the parkas, making sure that there was no fluctuation in the tones on the painted surface of the Endurance. There’s a degree of exactitude that needs to be achieved when it comes to the details of the tactile nature of that world. Every piece of linen and rope, every piece of wood, all the hair on the dogs, and the colour of the clothes needed very specific attention. AI processes as they exist right now cannot afford that attention.”
Norton says, “A wash technique really allows the black and white imagery to create all the value and contrast difference within the frame. We're just simply adding colour rather than adding any other kind of visual information or overriding the black and white. We didn't want to create a highly saturated result. We wanted the material to still feel aged.”
BigStar also did graphic design and title sequence for the show as well as taking in all the survey data and high rez photography to create a 3D model of the wreckage.
“The 3D model serviced several points throughout the film as far as explaining the status of the wreck and also giving us material for the title sequence itself,” Norton says.
The doc finds parallels with Shackleton's story and the recent expedition to find the sunken ship. “Thematically they were very similar,” says Eisenhardt. “Both expeditions got stuck in the ice, they suffered ups and downs and harsh weather. Both are tales of friendships. To make the story work, you had to find specifics that kind of spoke to each other. The idea of exploration as pushing the boundaries is a universal theme. But finding those moments in both the Shackelton footage and the new expedition that ‘talk’ to each other so that it would enhance both stories takes a lot of time. It took months to figure out the right percentage of each story to include.”
Footage of the 2022 expedition itself amounted to over 500 hours, the bulk of which was from shooting three cameras onboard the remote operated submarine that would spend six hours at a time underwater searching for and filming the wreck. The film’s co-director Natalie Hewit was onboard the Agulhas II to supervise.
“We watched everything, literally,” says co-editor Simona Ferrari. “We had a team that went through the footage shot 3000 meters below sea level so instead of having six hours’ worth we got maybe 2-3 hours per dive.”
The documentary also narrates portions of the 1914-16 expedition in the words of Shackelton and his crew who all kept diaries. “There were thousands and thousands of pages, some of it unpublished,” Eisenhardt relates. “All that had to be copied and sorted for the best material and from there we began a discussion about AI. It was a real discussion about whether using AI to voice their words was the proper thing to do. Our conclusion, was that AI is the perfect tool for this situation.”
The alternative might be to have some celebrity or actor pretend they're Shackleton but if they could use AI to replicate his voice speaking words he wrote, that felt closer to the truth.
It was easier said than done though. The only recording of Shackleton’s voice lasts just four minutes and was made on an Edison Phonograph wax cylinder.
“The noise on the recording was as loud as his voice, and he was speaking strangely since he was projecting into a giant megaphone. It was unusable.”
They turned to Ukrainian AI voice specialists Respeecher which, among other work, had resynthesized Mark Hamill’s voice for a young Luke Skywalker in an episode of The Mandalorian. They were able to scrub away the noise to leave a clean vocal track. Meanwhile, the crew’s diaries were whittled down to the raw material that they could exact dialogue from. They hired an actor with a neutral accent to record the dialogue, giving the appropriate intonations, from which Respeecher made a model. They then applied their AI app using the voices of Shackelton and his crew.
“Everybody knew the story of The Rescue because it had been headline news for over a week. People know the outcome of Shackelton’s heroism. I think what matters to me is finding out who these people are and what makes them tick. That means digging deeper into the characters and wondering why did what they did. We started from asking what their motivation is to do what they do and we build up from that.”
The same filmmaking team are already embarked on another project, this one about climbing Mount Everest / Chomolungma.