Their paths don't cross frequently these days, but put Paul McCartney and Ringo Starr in a room together and within a heartbeat they're displaying the easy but deep camaraderie forged more than half a century ago on their way to becoming the biggest rock band on the planet.

The friendship created some 60 years ago among four lads who grew up blocks apart from one another is one that's front and center in the Ron Howard-directed documentary about the Beatles as a performing unit, “Eight Days a Week: The Touring Years,” that opens nationally in mid-September.

“Eight Days a Week” chronicles the astonishing wild ride the Beatles were on during the first half of their eight-year life as a group, through the height of Beatlemania. Howard, who vividly recalls watching their live U.S. performance debut in 1964 on “The Ed Sullivan Show” just before he turned 10, agreed to direct the documentary in hopes of illustrating to a new generation just how extraordinary the group and their journey was.

“I felt it was incumbent upon me to try to do two things,” Howard, 62, explained. “One was to honor the fans who really would know the difference, the really dedicated fans, of which there are zillions.

“But I also thought it was even more important to try to tell a story that would convey to people who really have no idea — I'm thinking of the millennials, I suppose, people who have grown up with the music and think they know something of the story — the intensity of the journey and the impact they had.”

Much of the 95-minute film is built on crowdsourced material ferreted out over a long period. Those efforts date to the early 2000s, when a film archivist company, One Voice, One World, asked Apple executives to commission it to locate footage from fans who were using increasingly popular home-movie cameras flooding the market around the time Beatlemania erupted globally in 1964.

The project stalled, then was revived a few years ago by Jeff Jones, head of the Beatles company, Apple Corps Ltd., who brought in producer Nigel Sinclair to see it through for his Los Angeles-based White Horse Pictures. Sinclair had been a producer of the 2006 Martin Scorsese-directed Bob Dylan documentary “No Direction Home” and the 2011 George Harrison life story, also directed by Scorsese, “Living in the Material World.”

Along with the crowdsourced footage, “Eight Days a Week” incorporates new interviews with McCartney and Starr along with archival interviews of John Lennon and George Harrison and other material provided by Lennon's widow, Yoko Ono, and Harrison's widow, Olivia Harrison.

The making of the film turned into an opportunity to revisit and clarify some facets of what often was a giant blur when they were in the midst of it.

“The stuff you remember when you see the footage, and the old photographs, it helps,” said Starr, 76.

McCartney quickly picked up the conversation, saying: “It jogs all the memories. That's one of the joys about seeing the film.”

Both pointed to a section of the film that discusses a rider in the Beatles' concert contracts specifying that they refused to perform in segregated venues while touring the U.S.

“To see in the film that we actually put it in our contracts … we didn't remember that,” McCartney, 74, said. “I was very impressed with that. It was very cool.”

It was a revelation to Howard as well.

“I knew about their antiwar stances later,” he said. “But I had no notion (about their position on racial equality). That was courageous stuff at that time.”

Among many scenes that should be new even to the most ardent Beatles fans is footage of their final concert at Candlestick Park in San Francisco on Aug. 29, 1966. That was the moment they quit touring to focus on advancing their music in the recording studio. Acall was sent out to Beatles fans worldwide by way of traditional media and social media platforms soliciting film footage, photos or recordings any fans kept of the group from the short few years they spent touring the globe from 1963 to 1966.

“A proverbial little old lady called in. She said, ‘I went to Candlestick show, and I sat in Row 8, and I took my camera,'?” Sinclair recalled during a separate interview in Las Vegas. “She said, ‘Naturally, I filmed all of the last song and all of the end of the show. I've got it in a can. It's under my bed; I'm not sure if it still works. Would you like me to send it to you?'

“We realized that she didn't realize she had something she could probably sell, so we actually explained to her that we would pay her for it,” Sinclair said. “We sent somebody up to San Francisco to pick it up, because we didn't want to lose it, and it was the holy grail. For our story, we wanted to capture the boys running off the stage for the very last time in history. So we have a lot of things like that.”

It's already made a positive impression on at least one person familiar with the band.

“We never really heard the Beatles,” said McCartney, referring to the screaming that accompanied their performances. “We've certainly never seen them, because we were never out front. But I'd hear whoever I was standing nearest, whatever amp they were playing. … So it is kind of nice now to hear us mixed properly.”

The choice to stop touring struck Howard as a bold artistic move.

“One of the things I didn't anticipate was how, I thought, kind of courageous the choice was to leave, because that's how they were making (most of) their money,” Howard said. “They were hugely famous; this is what everybody wanted. Yet their creative integrity was what was driving them, and their sense of what's worthy of their time, just as people on the planet.”

randy.lewis@latimes.com