Debra Granik likes to take her time. Since her first, award-winning short, Snake Feed, debuted at the Sundance Film Festival in 1998, the 55-year-old director has made just three features and a doc in the intervening 20 years. Indeed, in the gap between her latest movie and the last, Winter’s Bone, Granik has seen that film’s breakout star, Jennifer Lawrence, win an Oscar and get nominated for three more.

Making its international premiere in Directors’ Fortnight, the new film, Leave No Trace, stars Ben Foster as an army veteran who lives a nomadic existence with his teenage daughter (a terrific performance from newcomer Thomasin McKenzie). Unusually for Granik, the project was not self-generated.

“Two producers gave it to us,” she says. “They had loved the story—the novel My Abandonment by Peter Rock—and then passed it [to us]. They asked me and my producing partner—she’s someone I write with as well, and her name is Anne Rosellini—whether we liked it and whether we would want to be involved. And we really responded very strongly. We liked both the characters very much, loved the setting, loved the intensity of the insularity of the story.”

But why did it take so long to follow up Winter’s Bone? “The process of starting up a new film is one of looking through a lot of material and trying to find something you really like,” she says. “And it does sometimes take a minute. We’re always on the search for a novel, or a source, or an existing screenplay, or writing something ourselves that turns us on. But because films cost a lot of money to make, and a huge amount of effort to get the people to rally, you have to really like it; you can’t just semi-like it. Getting to ‘really like’ is the part that takes the minute.”