Archival photographs of Marley are just some of the sources in a new documentary.

Bob Marley wouldn’t have liked the idea of someone making a film about him. A notoriously reluctant interviewee, Marley seldom spoke to reporters on camera. This posed a challenge for Kevin Macdonald, the director of “Marley,” an exhaustive new documentary about the legendary reggae singer.

“You can’t rely on his voice in the film,” Macdonald says. “So, I had to rely on the voices of other people. It became this oral history.”

Macdonald traveled to Marley’s home country of Jamaica to interview dozens of people who knew him best: his wife, Rita, children Ziggy and Cedella and members of his band, the Wailers. Macdonald also tracked down Marley’s first music teacher, his mistresses and even his white cousin, Peter Marley.

“I thought the way of building up a portrait of him, of showing the man behind the myth and the legend, is by talking to all these people and building up a mosaic image of Bob,” Macdonald says.

Spanning Marley’s entire life — from his birth to Cedella and Norval Marley in 1945 to his death from cancer in 1981 — “Marley” sets out to create a definitive portrait of the man who brought reggae to the masses. With unprecedented access to photographs and music through the full support of the Marley family, Macdonald wanted to show the Marley beyond the iconic image on a T-shirt. The film’s release follows a path as unconventional as the singer’s: It will be available for viewing Friday in its entirety on Facebook, the same day it arrives in theaters.

Macdonald delves particularly deeply into Marley’s mixed-race heritage. Very little is known about Marley’s father, a white Englishman who left Marley’s mother shortly after marrying her. “I found out enough to know he was a bit of a fantasist,” Macdonald says. “He called himself Captain Marley but he wasn’t ever actually a captain. He was only a private in the army, and he never saw active service.”

Macdonald thinks Marley’s mixed-race background and outsider status pushed him toward music and Rastafarianism.

“Music was a way of finding an identity and a way of expressing himself,” Macdonald says. “The reason he managed to pull himself out of his background and the enormous poverty he was born into was imagination and incredible willpower and determination.

“But I think also that the aspect of him being from the third world is so important,” Macdonald adds. “He speaks to people. If you grew up in the slums, Bob speaks to you. Bob speaks to you because he understands hardship and he understands what it’s like to not be one of the chosen people.”

Landmark E Street Cinema, 555 11th St. NW; $8-$11; 202-452-7672. (Metro Center)