THE documentary Under African Skies, which opens this week in New York and Los Angeles, will remind many people of what they love about Graceland, the Paul Simon album whose 25th anniversary the film celebrates. Seeing it will also be a jolt for those who have forgotten the world of bitterness into which it was born.

Most of the film is music and motion and commotion: Ladysmith Black Mambazo high-stepping and smoothcrooning, the guitarist Ray Phiri doing his swivel-hip thing, drums and bass pulsing under Simon’s rolling, tumbling New-York-surreal lyrics. People singing and swaying at huge open-air concerts in London and Lesotho.

Others marching and getting beaten in Johannesburg. Penny whistles and accordions. Billy clubs and tear gas.

You watch and think, how long ago 1986 feels. Nelson Mandela was still in prison. South Africa was a pariah.

Anger over apartheid raged in Congress and on college campuses. Ronald Reagan vetoed a tough sanctions bill, but Congress overrode him; even Republicans were willing to embarrass the president to stay on the other side of that evil. “We have waited long enough for him to come on board,” Senator Mitch McConnell, R-Ky, then in his first term, said of Reagan.

This was the maelstrom Simon entered, on a mission having nothing to do with politics. He had South African music in his head, planted there by a bootleg cassette of “accordion jive” by the Boyoyo Boys, strangely similar to the 1950s rock ‘n’ roll he had grown up with. Eager to trace the sound to its source, he went to Johannesburg with his engineer, Roy Halee, in 1985. They gathered musicians and recorded much of Graceland there, despite a UN boycott that forbade any cultural involvement with the apartheid regime.

“I was very aware of what was going on politically,” Simon says in the film, though later he admits he really wasn’t.

Harry Belafonte had urged him to get the blessing of the African National Congress before going, which he didn’t do. Simon bristled at such constraints, and decided that the welcome and cooperation he got from black musicians was all the approval he needed.

Graceland was his biggest hit, a global phenomenon, but success made it a target. Anti-apartheid protesters picketed the world tour.

African-American college students accused him of doing what white musicians always do when they find black music that’s irresistibly good.

Boycott leaders deplored the thought of an outsider sidestepping their global campaign without permission or apology and bringing a group of South African artists along with him.

That dissonance gives the film its most riveting sequence, filmed last year in Johannesburg. Simon is sitting on a couch next to Dali Tambo, son of the African National Congress leader Oliver Tambo and a founder of Artists Against Apartheid, a leading force for the boycott.

Maybe so, though at that time, to that government, he was far more equal than they were. His remark about wages is revealing. These were essentially session guys hired to make a Paul Simon record, though the film makes clear that he came to see them as collaborators and friends. Some accused Simon of going on “cultural safari,” though he has a ready answer. “A ‘safari’ is already derogatory,” he said in a phone interview the other day.

“You’re going to passively observe or to kill. I was going to learn.” Learn he did, not always happily.

Simon tells a story in the film of how easily racial stereotyping could poison even the making of music, and how easily irritation could bleed into something uglier. “I significantly underestimated what it would be like,” he told me. “I had no experience; I sort of related it to our country and then put a multiple on it, but it was insufficient. Racial tension doesn’t really describe it. What it was, was fear.” That’s one of the wonders of Graceland, a work of art created at a time of hatred and rancor that burst above it anyway. Nothing in Graceland explicitly challenges white supremacism, though all of it does. The regime is dead; apartheid’s defenders are gone and forgotten. Reagan is remembered for other things. Righteous anthems like Peter Gabriel’s “Biko” are trapped in their time.

But Graceland is not. It’s as alive and surprising now as it was then, when South African artists shared their genius with Simon. I hope it doesn’t spoil the ending of the encounter between Tambo and Simon to say it affirms the power of music, the value of graciousness in disagreement, and the wisdom of moving on.