More than 65 years after it was suppressed by the Army, a powerful and controversial John Huston documentary about soldiers suffering from the psychological wounds of war has been restored by the National Archives and debuts Thursday on the Web.

“Let There Be Light” portrays GIs just back from the battlefields of Europe and the Pacific — trembling, stuttering, hollow-eyed and crying. Using a noir style, Huston filmed dozens of soldiers in unscripted scenes from their arrival at an Army psychiatric hospital on Long Island through weeks of often successful treatment, culminating in their release to go home.

The restoration “reveals the film’s full force,” said Scott Simmon, a film historian and English department chairman at the University of California, Davis.

Even after the Army approved its release in 1980, the poor quality of the prints and, in particular, the garbled soundtrack made it almost impossible to understand the whispers and mumbles of soldiers in some scenes.

The restored soundtrack “makes the film speak in a way it never could before,” Simmon said in an interview.

The film is striking for its potential relevance for a new generation of veterans returning from Iraq and Afghanistan, showing soldiers struggling to cope with what was then commonly called shell shock, and more formally labeled psychoneurosis, but is now known as post-traumatic stress disorder.

“We hope that by making ‘Let There Be Light’ freely available — and by drawing attention to it — that the courageous documentary will find the audience it was intended to serve,” said Annette Melville, director of the National Film Preservation Foundation, which funded the restoration.

The film, commissioned by the Army near the end of the war, was intended to prepare Americans for the realities of what combat had done to those sent to war but also to show that their psychological wounds could often be treated with therapy.

But when it came time to release the film, the Army balked, claiming it violated the privacy of the soldiers involved. Huston never bought that explanation.

“I think it boils down to the fact that they wanted to maintain the ‘warrior’ myth, which said that our Americans went to war and came back all the stronger for the experience, standing tall and proud for having served their country well,” Huston wrote years later in his autobiography.

Sympathetic portrayals of wartime post traumatic stress “were swept under the rug” until after the Vietnam era, Simmon said in an essay he wrote about the film’s restoration for the preservation foundation. “Let There Be Light” is considered groundbreaking in documentary film history for its almost unprecedented use of unscripted interviews, according to Simmon.

The film is also striking for showing the free and casual interaction of African American and white soldiers being treated at the integrated Army hospital. After the film was pulled, the Army commissioned a remake using actors to reenact the scenes filmed by Huston, giving all the speaking roles to whites.

“Let There Be Light” was the last in a World War II trilogy commissioned by the U.S. Army Signal Corps from Huston, who had already achieved some renown as the director of “The Maltese Falcon” when he joined the Army after Pearl Harbor.

His first Army film, “Report from the Aleutians,” caused relatively little controversy but the second, “The Battle of San Pietro,” was nearly shelved for its harrowing combat footage in Italy before Gen. George C. Marshall, the Army chief of staff, intervened.

For his third production, Huston shot close to 70 hours of film, using multiple cameras running continuously on doctors and patients. Huston had his father, the actor Walter Huston, narrate.

The Army wanted to call it “The Returning Psychoneurotics,” but Huston thought a phrase from the biblical creation story was more appropriate. “Let There Be Light” conveys the narrative arc of the film, from “noir-inflected shots” of gangplanks and smoke-filled hospital interviews to the sunlit baseball field shown in the film’s uplifting conclusion, Simmon noted.

Huston considered the film “the most hopeful and optimistic and even joyous thing I ever had a hand in.”

But to his dismay, the Army restricted screenings to a few military venues. All the soldiers shown in the film signed releases, according to Huston, who said he later discovered the signed documents had “mysteriously disappeared.”

The Museum of Modern Art in New York arranged for a public premiere in June 1946, but minutes before the show, two military policemen confiscated the print.

Huston directed some of his finest movies soon after leaving the Army, including his second film after the war, “Key Largo,” in which Humphrey Bogart portrays a disillusioned veteran who confronts gangsters.

Over the years, there were calls from Hollywood for the Army to release “Let There Be Light,” an effort that succeeded in 1980 with backing from Vice President Walter Mondale and Jack Valenti, president of the Motion Picture Association of America.

It received mixed reviews, in part because the once-innovative documentary techniques seemed badly dated, Simmon said. Moreover, the editing of the film, compressing hours of therapy into a few minutes, makes some of the cures appear “strangely easy,” as Simmon noted, leading to criticism that the movie raised unrealistic expectations for miracle fixes to serious mental trauma.

In 2010, “Let There Be Light” was placed in the Library of Congress’s National Film Registry to be preserved because of its historic significance.

The soundtrack was restored by Chace Audio by Deluxe, which converted it to digital audio files and used restoration technology to remove the hiss and pops and correct irregularities. The print was restored by the National Archives’ motion picture preservation lab in College Park, which produced a new negative using a “wet-gate” process that removed scratches and abrasions.

“In some senses, it was routine, but knowing the history of the film, we gave it additional attention,” said Christina Kovac, a supervisory motion picture preservation specialist.

The film will be available on the National Film Preservation Foundation Web site through August.