NEW YORK — Paul Thomas Anderson premiered his first documentary, “Junun,” on Thursday at the New York Film Festival, unveiling a sonically rich portrait of Indian musicians recording an album with Radiohead’s Johnny Greenwood.

The film, just under an hour long, plunges into their recording sessions, along with Israeli composer Shye Ben Tzur, during a threeweek trip to Rajasthan in northwestern India. With scant interviews, and hardly any words from Greenwood, “Junun” instead captures the musicians in full thrall while recording in a 15th century hilltop fort in between occasional power outages.

“Junun,” which roughly translates as “madness of love,” will be released on the movie subscription platform MUBI on Friday. Its premiere at the New York Film Festival, where Anderson last year debuted his Thomas Pynchon adaptation “Inherent Vice,” was a lowkey affair without a Q&A with Anderson.

The film, too, came with little explanation. Greenwood, who has scored Anderson’s last three films (“There Will Be Blood,” “The Master” and “Inherent Vice”), would be considered by many to be the star of the documentary.

But the Radiohead guitarist remains largely in the background, thrust forward no more than the horn and percussion players of the Rajasthan Express. Their musical ability, sowed in generations of tradition, has a powerfully hypnotic effect.

Shooting digitally, and occasionally experimenting with drones that hover above the fort, “Junun” focuses on their intimate sessions of the East-West collaboration. When the electricity is running, there are few interruptions other than a handful of birds and the occasional nap.

“No toilet. No shower. But full power,” says one musician.

The resulting album, produced by Nigel Godrich, is to be released by Nonesuch in November.