Colourised footage brings WWI to life in Peter Jackson's new film Thou Shall Not Grow Old

Incredible colourised footage has brought the First World War to life after a painstaking project to memorialise troops by Kiwi director Peter Jackson.

Grainy video of soldiers in the bloody battle has been carefully remastered and turned into colour footage for the first time to mark the centenary of the conflict between 1914 and 1918.

Three-time Oscar-winning Lord Of The Rings film-maker Jackson used 100-year-old footage from Imperial War Museum archives to show it in previously unseen detail.

Over four years the award winner edited hundreds of videos to produce the final piece, which masterfully melts black and white scenes into brightly coloured clips.

The premiere in London next week, which will be attended by the Duke of Cambridge, will be followed by a Q&A with Jackson.

Jackson said: "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 - rather than be seen only as Charlie Chaplin-type figures in the vintage archive film."

The 90-minute film is narrated with interviews from 120 veterans, from 600 clips recorded in 1964. Jackson was adamant the soldiers should tell their own stories.

Old film was meticulously restored. Computers were used, not only to add colour to black and white footage, but to remove imperfections, fill splices and reconstruct missing frames from film that was shot with fewer frames per second than today.

Forensic lip readers, who usually work with the police determining what people say on silent security camera footage, were able to decipher the conversations that took place in the trenches and on the battlegrounds 100 years ago. Actors were hired to give the soldiers on screen a voice.

"There's been lots of documentaries made on the First World War...and I just decided for this one to strictly just use the voices of the guys that fought there," Jackson, director of the Hobbit and the Lord of the Rings series told Reuters on Tuesday.

"It's not the story of the war. It's the story of the human experience of fighting in the war."

Jackson told Sky News he was inspired by a life-long interest in the war in which his grandfather was a serving solider in the British Army.

"You didn't really notice them when they were all sped up and jerky, but suddenly they just come into a focus," he said.

Jackson said he reached through "the fog of time" to pull soldiers' First World War stories into the modern world in revitalised archive footage to be premiered in 3D at the BFI London Film Festival.