Asif Kapadia did more than 100 interviews with 80 people — friends, family and colleagues of the late singer Amy Winehouse — for his documentary Amy, about the iconic singer-songwriter. But it wasn’t easy.

“The biggest challenge initially was getting people to talk,” he tells The Hollywood Reporter of the film, which A24 will release in the U.S. on July 10. “It was a painful, recent memory. People hadn’t come to terms or dealt with what happened.”

Kapadia, who had the support of Winehouse’s music label Universal on the intimate film, would usually bring the subject of his interview into a recording studio, just the two of them, and speak to him or her in a small room with a microphone and the lights off.

“We’d just talk in the dark,” he says. “For many of them, it was a form of therapy to get things off their chest.”

Kapadia says the interviews were tough, but no one ever walked out and there were never any blowups while they were talking about the life of the singer, who died in 2011 at age 27 from alcohol poisoning.

Winehouse’s family, including her father, Mitch Winehouse, who was interviewed extensively, first saw a cut of the film in late 2014. But in April, just two weeks before the film would premiere in Cannes in a midnight screening May 16, the Winehouse family chose to “disassociate” itself from the film.

“I felt sick when I watched it for the first time. Amy would be furious,” said Mitch, who also accused the filmmakers of not sampling enough people from Winehouse’s life and blaming him for her addictions. But Kapadia says he’s tried to keep the focus of the film on Winehouse’s talent and passion for music.

“My angle was to make a film that was honest and truthful to Amy,” he says. “There was a lot of tension, a lot of voices around her that made it difficult for her to deal with issues. I think that is difficult for people to see because it’s turning the mirror around.”

Winehouse’s boyfriend at the time of her death, Reg Traviss, also has voiced his frustration with the doc, claiming that his presence was mostly cut from the project.

“The story is really about her and her creative period, which was in her earlier years,” says Kapadia, who says Traviss is included in the film, just not as much as in earlier versions. “Sadly, in the last five years of her life, she didn’t make any music. She stopped living, almost, and was stuck in a roadblock when it came to creativity.” [The Hollywood Reporter]