A documentary based on a home movie shot by an American in 1938 provides a look at the vibrancy of a Jewish community in Europe just before the Holocaust.AMSTERDAM — Glenn Kurtz found the film reel in a corner of his parents’ closet in Palm Beach Gardens, Fla., in 2009. It was in a dented aluminum canister.Florida’s heat and humidity had nearly solidified the celluloid into a mass “like a hockey puck,” Kurtz said. But someone had transferred part of it onto VHS tape in the 1980s, so Kurtz could see what it contained: a home movie titled “Our Trip to Holland, Belgium, Poland, Switzerland, France and England, 1938.”The 16-millimeter film, made by his grandfather, David Kurtz, on the eve of World War II, showed the Alps, quaint Dutch villages and three minutes of footage of a vibrant Jewish community in a Polish town.Old men in yarmulkes, skinny boys in caps, girls with long braids. Smiling and joking. People pour through the large doors of a synagogue. There’s some shoving in a cafe and then, that’s it. The footage ends abruptly.Kurtz, nevertheless, understood the value of the material as evidence of Jewish life in Poland just before the Holocaust. It would take him nearly a year to figure it out, but he discovered that the footage depicted Nasielsk, his grandfather’s birthplace, a town about 30 miles northwest of Warsaw that some 3,000 Jews called home before the war.Fewer than 100 would survive it.Now, the Dutch filmmaker Bianca Stigter has used the fragmentary, ephemeral footage to create “Three Minutes: A Lengthening,” a 70-minute feature film that helps to further define what and who were lost.“It’s a short piece of footage, but it’s amazing how much it yields,” Stigter said in an interview in Amsterdam recently. “Every time I see it, I see something I haven’t really seen before. I must have seen it thousands and thousands of times, but still, I can always see a detail that has escaped my attention before.”Almost as unusual as the footage is the journey it took before gaining wider exposure. All but forgotten within his family, the videotape was transferred to DVD and sent to the U.S. Holocaust Memorial Museum in Washington in 2009.“We knew it was unique,” said Leslie Swift, chief of the film, oral history and recorded sound branch of the museum. “I immediately communicated with him and said, ‘If you have the original film, that’s what we want.’”The Holocaust museum was able to restore and digitize the film, and it posted the footage on its website. At the time, Kurtz didn’t know where it had been shot, nor did he know the names of any of the people in the town square. His grandfather had emigrated from Poland to the United States as a child and had died before he was born.Thus began a four-year process of detective work, which led Kurtz to write an acclaimed book, “Three Minutes in Poland: Discovering a Lost World in a 1938 Family Film,” published by Farrar, Straus and Giroux in 2014.Glenn Kurtz, who found the original footage shot by his grandfather in his parents’ closet in Florida, later wrote a book about the significance of the film.Stigter relied on the book in completing the film, which is co-produced by her husband, Steve McQueen, the British artist and Academy Award-winning director of “12 Years a Slave,” and narrated by Helena Bonham Carter. It has garnered attention in documentary circles and has been screened at Giornate degli Autori, an independent film festival held in parallel with the Venice film fest; the Toronto International Film Festival; Telluride Film Festival; the International Documentary Film Festival Amsterdam; and DOC NYC. It was recently selected for this month’s Sundance Film Festival.Nasielsk, which had been home to Jews for centuries, was overtaken on Sept. 4, 1939, three days after the German invasion of Poland. Three months later, on Dec. 3, the entire Jewish population was rounded up and expelled. People were forced into cattle cars, and traveled for days without food and water, to the towns of Lukow and Miedzyrzec, in the Lublin region of Nazi-occupied Poland. From there, they were mostly deported to the Treblinka extermination camp.“When you see it, you want to scream to these people run away, go, go, go,” Stigter said. “We know what happens and they obviously don’t know what starts to happen, just a year later. That puts a tremendous pressure on those images. It is inescapable.”Stigter stumbled across the footage on Facebook in 2014 and found it instantly mesmerizing, especially because much of it was shot in color. “My first idea was just to prolong the experience of seeing these people,” she said. “For me, it was very clear, especially with the children, that they wanted to be seen. They really look at you; they try to stay in the camera’s frame.”A historian, author and film critic for a Dutch national newspaper, NRC Handelsblad, Stigter worked on this film, her directorial debut, for five years. She started it after the International Film Festival Rotterdam invited her to produce a short video essay for its Critic’s Choice program. Instead of choosing a feature film, she decided to explore this found footage. After making a 25-minute “filmic essay,” shown at the Rotterdam festival in 2015, she received support to expand it into a feature film.“Three Minutes: A Lengthening” never steps out of the footage. Viewers never see the town of Nasielsk as it is today, or the faces of the interviewees as talking heads. Stigter tracks out, zooms in, stops, rewinds; she homes in on the cobblestones of a square, on the types of caps worn by the boys, and on the buttons of jackets and shirts, which were made in a nearby factory owned by Jews. She creates still portraits of each of the 150 faces — no matter how vague or blurry — and puts names to some of them.An image from the home movie showing Moszek Tuchendler, 13, on the left, who survived the Holocaust and became Maurice Chandler. He was able to identify many other people in the footage of the town where he grew up.United States Holocaust Memorial MuseumMaurice Chandler, a Nasielsk survivor who is in his 90s, is one of the smiling teenage boys in the footage. He was identified after a granddaughter in Detroit recognized him in a digitized clip on the Holocaust museum’s website.Chandler, who was born Moszek Tuchendler, lost his entire family in the Holocaust; he said the footage helped him recall a lost childhood. He joked that he could finally prove to his children and grandchildren “that I’m not from Mars.” He was also able to help identify seven other people in the film.Kurtz, an author and journalist, had discovered a tremendous amount through his own research, but Stigter helped solve some additional mysteries. He couldn’t decipher the name on a grocery store sign, because it was too blurry to read. Stigter found a Polish researcher who figured out the name, one possible clue to the identity of the woman standing in the doorway.Leslie Swift said that the David Kurtz footage is one of the “more often requested films” from the Holocaust Museum’s moving picture archives, but most often it is used by documentary filmmakers as stock footage, or background imagery, to indicate prewar Jewish life in Poland “in a generic way,” she said.What Kurtz’s book, and Stigter’s documentary do, by contrast, is to explore the material itself to answer the question “What am I seeing?” over and over again, she said. By identifying people and details of the life of this community, they manage to restore humanity and individuality.“We had to work as archaeologists to extract as much information out of this movie as possible,” Stigter said. “What’s interesting is that, at a certain moment you say, ‘we can’t go any further; this is where it stops.’ But then you discover something else.” More