Digital effects, lip-readers, and artistic licence: how Peter Jackson made They Shall Not Grow Old

Despite being comprised of nothing but archive footage of the First World War, They Shall Not Grow Old is very much a Peter Jackson movie. With its hypereal digital effects, eye-popping use of modern technology and fascinating behind-the-scenes process, it is an unexpected if entirely fitting next step for the director best known for bringing the fantasy worlds of JRR Tolkien to vivid life.

Approached two years ago by the Imperial War Museum to sift through 100 hours of largely unseen historical footage of soldiers in moments between battle, Jackson was asked to fulfil just one brief: that he somehow use the footage “in a fresh way”.

Initially puzzled by the request, Jackson eventually pondered restoring the footage using the same technological prowess that has dominated his recent fictional output, with a test on four minutes of the material inspiring him to go further – a planned 30-minute special ultimately became a feature documentary, which will be broadcast this weekend on BBC One before being distributed to every secondary school in the country.

Through colourising the black-and-white film and digitally enhancing what was for years deemed unwatchable, the resulting documentary is arguably the closest modern audiences will get to the experiences of real World War One soldiers.

Accompanied by similarly unearthed voiceover of war veterans and dialogue spliced in using modern filmmaking trickery, the film marks a radical departure from much of what we’ve come to expect from historical documentaries. There are no jittery frames here.

“The First World War, for good or for worse, is defined in people’s imaginations by the film that is always used in all the documentaries,” Jackson told ITV News last month. “And it looks bloody awful, for obvious reasons. There were technical limitations and also a hundred years of age – of shrinkage and duplication and starches.”

A long-time World War One buff with a seven-strong collection of authentic battle planes purchased at auction over the years, Jackson grew up emulating his father’s own interest in the conflict, having seen his father recall his own memories of battle – Sergeant William Jackson, who died in the Forties, fought for the British army, with They Shall Not Grow Old dedicated to his memory.

“In a funny way, I am also a child of the First World War,” Jackson told the History Extra podcast. “My dad emigrated to New Zealand, where he met my mum, because his father had admired how the soldiers fought… I liked doing this movie because it was about the common experience of the soldier. I felt that I was learning about what my grandfather went through.”

Jackson has admitted that the hardest part of the restoration wasn’t in fact the elaborate sharpening or visual editing, but cleaning up the original black and white footage, much of which was damaged with scratches, tears and chemical splotches. To fix, images were sharpened and airbrushed, while much of the footage was retimed – 13 frames per second was the standard for historic films, compared to 24 frames per second today. That retiming meant that some frames vanished altogether, leaving empty spots of around three or four frames in between movements, ones that had to be filled in later with a computer.

“It amazed me how well they could do it now,” Jackson told the Daily Mail. “If you tell the computer that this is 15 frames a second but we want it to be 24, you just push a button. There’s no human involvement, the computer will actually take the frames before and after and create these frames that don’t exist with the original material. It create its own frames. It’s incredible the results that you get.”

Next was colourisation. Jackson has said that the process isn’t quite as difficult as it looks, rather being “just very labour intensive”, but the level of detail is staggering. Instead of merely painting in each frame, visual effects company Stereo D immersed themselves in research provided by historian Pete Connors, meaning each restored shot could feature soldier-specific details, from individual ranks to accurate uniform colours.

Jackson himself additionally went on several solo trips through Flanders and France taking photographs of many of the battlefields, eager to replicate specific colours and textures as authentically as possible. Other elements were more creatively inspired – when a soldier is seen wearing something not traditionally part of their uniform, such as a private dress shirt, Stereo D artists deliberately used colours that would help break up the visual monotony of traditional uniforms and create a more visually sumptuous frame.

“I would describe the colour process as mostly forensic but also creative,” Stereo D colourist Milton Adamou has said. “On one hand we’re recreating a photoreal world, striving to provide an accurate interpretation of the environment and the people within it. Everything in the frame is dissected and analysed, then cross-referenced against records from multiple sources… Then on the other hand we had some creative freedom to hone in on details that will be visually interesting to the audience.”

The process as a whole involved something known as “rotoscoping”, in which every element of a frame is traced and isolated before being coloured and shaded. 3D tracking from computer-generated models were additionally mapped onto the frames in order to enhance facial detail. It creates an effect that occasionally stumbles into “uncanny-valley” territory, with almost too much detail in certain shots, but it’s still undeniably impressive.

Such a process has been a controversial one, however, with some critics arguing that “colourising” black and white footage often disregards accuracy in the pursuit of more modern audience-friendly aesthetics. But Jackson has insisted his decision to “colour in” World War One had a purpose beyond the purely visual.

“The war was a colour war,” he told the Daily Mail. “We were trying to make a film where you’re listening to the people that were there and you’re seeing it as they saw it. They saw it in colour, not in black and white.”

Jackson’s interest in capturing the sights and sounds of the men themselves extended to the film’s mode of storytelling. Unlike the typical documentary style we’re most familiar with, there is no overriding narrator in Jackson’s film, no voiceover or talking head offering context. Instead the soldiers themselves act as our guides, Jackson and his team culling audio recorded for a 1964 BBC series titled The Great War, which featured over 120 veterans speaking about their experiences in the conflict.

These recollections, recorded just a few years after the war itself, are awash in detail, with many of the interviews being heard for the very first time. Jackson and his team listened to over 600 hours of audio footage in order to find the most vivid and moving snapshots to include.

“It was their lack of self-pity that surprised me,” Jackson told History Extra. “We look on these guys with an enormous sort of pity now. We think that we sent these men into this industrial grinding machine. But they certainly didn’t think that was what was happening to them – there was no feeling sorry for themselves.”

Speaking further to The Sunday Times, Jackson added that the audio means we can now “see the clowns, the troublemakers, the grumpy ones… There are a lot of laughs. Many veterans say it was an escape from a boring home or dull job. An incredible adventure. They don’t quite talk in the way you would expect people from the war to speak. It was the first time many had travelled overseas. It was like a Boy Scout camp. That’s what comes across.”

Audio from The Great War makes up the bulk of They Shall Not Grow Old’s soundscape, but other elements are faked: the various shouts and dialogue snippets heard in much of the documentary’s archive footage were supplied by professional actors, reciting scripts put together by a forensic lip reader who had studied hours of silent footage and filled in the missing audio.

Particularly striking is how innocuous much of the dialogue is – soldiers making small talk and laughing, with generic discussion of strategies or “the mission” noticeably absent. Among the dozens of programmes and documentaries commissioned this year to commemorate the centenary, it is debatable whether our veterans have ever been more humanised.

“I wanted to reach through the fog of time and pull these men into the modern world, so they can regain their humanity once more,” Jackson told Sky News. “Rather than be seen only as Charlie Chaplin-type figures in the vintage archive film. You don’t really notice them when they’re all sped up and jerky, but [now] suddenly they just come into focus.”

They Shall Not Grow Old is in cinemas across the UK and will be shown on BBC Two on November 11, at 9.30pm