The "Warsaw Rising" docu-fiction, which hit Polish screens on Friday, chronicles the country's 63-day insurrection against its Nazi German occupiers.
The remastered silent footage — enhanced by modern colouring and an audio track — brings to life the World War II rebellion that sparked bloody Nazi reprisals, destroyed much of Warsaw and left 200,000 of its residents dead.
The script revolves around two fictional cameramen, brothers Witold and Karol, who risked their lives to document a city mired in combat.
Their faces are never shown, but their narration guides the viewer through the events of the uprising, starting with the battles, the early victories, the enthusiasm of the insurgents and civilians.
Then come the setbacks and the revolt's eventual failure, leaving Poland's occupied capital as little more than a smouldering heap of rubble.
The Warsaw uprising was launched by the Home Army on August 1, 1944. Around 50,000 insurgents in the city were secretly mobilised by the London-based Polish government set up in exile after the 1939 Nazi invasion.
Adding in the audio track of battle sounds and dialogue was "one of the great challenges of the film", said Jan Komasa, who penned the storyline.
Police experts pieced together the dialogue by reading the lips of the insurgents, civilians and German soldiers. Actors then dubbed it in.
"In the scene where the residents carry slabs of sidewalk to build or reinforce barricades, our actors actually did the same when recording the dialogue to convey the effort and emotions," Komasa said.
"We didn't just want to record it in a studio."
The insurgents hid the film reels after the war, as the Warsaw uprising was a taboo topic under Stalinist rule.
One of the fighters smuggled some of the 20-hour footage over to the West, but a good chunk of the remaining stash was confiscated and destroyed by the Communist regime.
The Warsaw Uprising Museum acquired six hours worth of the black-and-white footage and pared it down to make the 1.5-hour colour film, said museum director and film producer Jan Oldakowski.
The museum also launched a parallel effort to identify the individuals in the footage. To date they have named 130, including 92-year-old Witold Kiezun.
"I have a very clear memory of when I was caught on camera," he told AFP, recalling the risk the real cameramen took to record the tragic weeks.
"It was a moment of victory after a battle that lasted six hours and enabled us to seize a command post and get hold of an automatic gun, which was worth more to us than gold."