Peter Jackson proved himself to be something of a wizard by bringing J.R.R Tolkien’s The Lord of the Rings novels to life as a transcendent film trilogy. Now the filmmaker is using groundbreaking technical innovations to breathe life into the awful conflict that inspired Tolkien’s fantasy writings in the first place: World War I.

Jackson’s new 3D documentary film They Shall Not Grow Old premiered in the United Kingdom on Oct. 16 in what was supposed to be a one-night only event. But the critical response (“astonishing,” “revelatory”) and box-office returns (£2,260, or $2,953 average per screen across 247 screens—excellent for a documentary, especially one with little publicity to date) were so overwhelmingly positive that the film is now being eyed for extended US and international theatrical releases, Deadline reports.

The New Zealand director and his team combed through 600 hours of archival footage from the Imperial War Museums in England and audio from the BBC archives to craft a look at life in the trenches on the Western Front of World War I in a deeply personal way that reviewers are saying has never been done before. Jackson’s team restored and colorized the footage, and converted it to three-dimensional, 24 frames-per-second digital film. The team also hired lip readers to help voice actors determine what the soldiers were actually saying in the footage. The archived audio is combined with voice recordings from the veterans themselves.

Variety compared the colorized, 3D footage in They Will Not Grow Old to the moment in The Wizard of Oz when Dorothy steps out of her sepia-toned world into lavishing Technicolor. “If this sounds like the world’s most state-of-the-art educational video, that’s exactly what it is,” Guy Lodge wrote for Variety. In the Guardian, Peter Bradshaw calls it a “visually staggering thought experiment,” adding that “the soldiers are returned to an eerie, hyperreal kind of life in front of our eyes, like ghosts or figures summoned up in a seance.”

Such dramatic technical changes could have easily felt like a gimmick, but it sounds as though Jackson avoided that pitfall, instead using the restorations to bring an immediacy to a war that until now has only been seen in grainy black-and-white footage. According to reviewers, the film is unsparing in its depiction of the trenches, showing in detail the horrid realities of the day.

Those realities were experienced by Tolkien himself as a 24-year-old British soldier at the Battle of the Somme in 1916. It was in the trenches where the author first came up with some of the ideas for his fantasy world, which Jackson would adapt for film 85 years later.

In the UK, the BBC will broadcast They Will Not Grow Old on Armistice Day, Nov. 11—exactly 100 years from the end of the war. We’ll update this story when international release dates are announced.