They knew the question before I was finished asking it. I was talking with filmmakers Aaron Aites and Audrey Ewell at the launch party for their documentary Until the Light Takes Us at The Knitting Factory. I was starting to inquire as to why a party celebrating a film about black metal bands wouldn’t include some, you know, black metal bands. Both began to smile, and Ewell laid it out for me in disarmingly simple terms.

“The distributor said to us, ‘Let’s have a party to promote the film,’” she explained, “and we said, ‘Let’s have our friends play it.’”

It turns out that their musically-inclined cronies have more of a penchant for chilled-out guitar ballads and looping, textured instrumental pieces than the head-thrashers chronicled in Aites and Ewell’s movie (opening at Cinema Village Dec. 4).

Not that this seemed to bother anybody at the well-attended show, which featured Papa M, Soft Circle, Rain Machine and Kevin Barker.

“It doesn’t really make a difference that the music played tonight isn’t the music in the movie,” observed Phil Gasper, 24, of Bushwick. “To meld the film and the party, you would have to fly in some actual Norwegian black metal bands, which I’m assuming isn’t feasible.”

Arthur Polendo, 44, all the way from Harlem, said that the draw for him wasn’t the film at all, but the chance to see Papa M. He reminisced about listening to the band’s 1999 album, Live from a Shark Cage, when he lived in San Antonio earlier this decade, getting lost in its hypnotic repetitions as he laid down cement for his parents.

“That album holds a sense of importance to me,” Polendo told me between sets.

The whole night had a feeling of laid-back magnanimity, with each act pausing to applaud the filmmakers. Kyp Malone, the TV on the Radio singer/guitarist and sole member of Rain Machine, literally raised the glass he brought on stage to toast the duo (he and Aites are both members of another band, Iran).

Malone also advised the warm but sedate crowd that it was all right to loosen up a bit, suggesting behavior that might not be out of place at a black metal show.

“If you ever just want to take your clothes off or light something on fire or just be a part of the show, don’t be afraid,” Malone told the audience, who responded with a few well-meaning whoops but, alas, no acts of public nudity or pyromania.