In a three-way phone interview, Mr. Zimmer and his collaborators, Benjamin Wallfisch and Lorne Balfe, described the process of creating what Mr. Zimmer called “the most intimate” work he’d ever made with Mr. Nolan. He was speaking from New York, where he was due onstage for his concert tour, and Mr. Balfe and Mr. Wallfisch from Los Angeles. Mr. Nolan spoke separately, from Vietnam, where he was taking a brief break from promotional duties. These are edited excerpts from the conversations.

Did you want the tension in the music to ever resolve?

HANS ZIMMER No. I have to believe that the tension will be unbearable and the outcome will be tragic, and in a way I have to pretend they will never get off the beach. If there are Method actors, I suppose I’m a Method composer. I went to the beach [at Dunkirk]. This sounds insane, but I was in the neighborhood, and I went knowing they were shooting there on the grayest, most foul day. I picked up a handful of sand and put it in a jar and took it with me. There was something good about having that next to me. And just generally when I start on a movie, the agonizing deadline, the unsolvable things, I’m tense most of the time.

Did you have other reference points?

ZIMMER It was very important to forget any other war movie I’d ever seen. This movie is more about time than any other movie we’ve ever done, about time running out.

LORNE BALFE I never thought of it as a war movie. I always thought of it as a thriller.

CHRISTOPHER NOLAN I asked Hans not to write any emotional music. What I said to him was I wanted objectivity — the way I wanted to make the film was, it’s all about suspense and tension and not at all about emotion. [The music cues he sent during shooting] were not emotional cues, they were very much about pacing. We could [use them via an iPad] when we were thinking about what the rhythms of the shots would be. This entire film was really very much about rhythm.

Did you use any unusual instrumentation?

ZIMMER There’s a double bass that’s played in the extremes, high register. I try to keep a small group of musicians playing always at the extremes of capabilities.