Most composers spend a few weeks, sometimes even a few months, on a film score. Ludwig Göransson spent a year and a half on Christopher Nolan’s “Tenet.”

The time-shifting spy thriller, last year’s cerebral challenge from the maker of “Inception” and “Interstellar” (currently being promoted for multiple craft awards, including Göransson for original score) forced the Swedish composer to come up with sounds and textures that had rarely, if ever, been heard in mainstream movies.

Göransson — an Oscar winner for “Black Panther,” an Emmy winner for “The Mandalorian” and a double Grammy winner for Childish Gambino’s “This Is America” — created more than five hours of music, a little more than two hours of which wound up in the movie. The mixture of guitar, synthesized sounds, processed and distorted orchestra is unlike anything he has written before.

The work started nearly two years ago, in February 2019, when composer and director met and spent “six or seven hours” just listening to, and talking about, music. “It was very clear, early on, that he really wanted to experiment,” Göransson tells Variety. This was three months before Nolan began shooting “Tenet.”

Göransson began by creating a 10-minute piece in his studio. “I tried to push it as much as possible, using tricks and things that I had collected during my years as a producer that I hadn’t really seen in films,” he says. Nolan liked it and encouraged the composer to continue.

“One of the first pieces I wrote was this big action sequence,” Göransson recalls. “He wanted something fast, propelling and aggressive.” Göransson worked on the composition for two months and one day received a call from Nolan in Tallinn, Estonia, where the director was shooting the movie’s terrorist-attack prologue.

“‘Can you make it more aggressive at the two-minute mark?’” Göransson remembers Nolan asking. The composer complied. Only months later, when he was invited to an early screening of edited footage, did Göransson realize that Nolan had paced the entire sequence to that early demo. “It was almost like a music video,” the composer says.

Throughout production and post-production, Göransson continued to write music based on the script and talks with the director. When he finally saw footage, he, Nolan, producer Emma Thomas and editor Jennifer Lame met every Friday for six more months after their return from Nolan’s many international locations to nail down the finished version.

Because one of the film’s key plot points is the concept of inverting time, Göransson pursued the notion of creating music that would play the same forward and backward. It was easier said than done, particularly when it involves musicians and not machines.

Göransson had three percussionists play a specific rhythm, which he then reversed in his computer. He played it for the musicians and asked them to emulate it, which he recorded and then reversed once more. And when he asked an entire orchestra to perform a similar task — during the pandemic, when 70 musicians were recording individually in their home studios, with their contributions to be mixed together later — it was even more complicated, requiring weeks of trial-and-error recordings during the late spring and early summer 2020.

What surprised Göransson was how effective the pandemic recordings turned out to be. “They created these interesting textures that worked perfectly for the sound Chris and I were after — something not of this world,” the composer says.

Much of the score is not recognizable as either electronic or traditionally orchestral. “So many of the elements are manipulated, processed or stretched,” Göransson explains. “I wanted it to sound like what the film looks like — very jarring to the ear. The music is very intense. It definitely takes you on a journey.”

There are even vocal sounds interpolated: Not just Travis Scott’s end-title vocal, which is sprinkled throughout Göransson’s score, but Nolan’s own breathing sounds. “We wanted something nasty and uncomfortable-sounding to represent Sator” (Kenneth Branagh’s Russian bad guy), the composer reports. “I recorded my breaths, but they weren’t raspy enough. So we recorded Chris Nolan’s. That worked.”