Given the Beatles' place in pop music over the past half-century, it's hard to believe that anything relating to the Fab Four might have gone missing.
But while creating a 50th anniversary digital restoration of the band's beloved feature film debut, "A Hard Day's Night," technicians at the Criterion Collection and Janus Films had to work around missing chunks from the first and last reels of the original negative.
Producer Giles Martin, son of original Beatles producer George Martin, also had to compensate for a missing stereo master of their early single "She Loves You," and instead use the existing monaural recording as part of a new audio mix of the film's dialogue and soundtrack.
All of which serves as a reminder that, early in 1964 when Beatlemania was exploding worldwide, musical immortality wasn't yet assured for the four lads from Liverpool.
"It was never my dad's intention to be digging this up after 50 years," Martin says. "I know it was his view that there would be more Beatles projects coming along down the line, and that some other young act would find the Beatles' spark, and the same phenomenon would be replicated.
"Now the Beatles have become this cultural phenomenon, and they are stamped in history, and that hasn't washed off in any way," Martin adds.
The younger Martin's mission in the restoration project was to create a surround-sound mix for what was initially a low-budget, black-and-white film with monaural sound. It "wasn't to be a modernized version of 'A Hard Day's Night,'" he says. "It's not as if I'm mixing 'Avatar.' It still should sound like it's 1964."
He adds that one "advantage of 5.1 (technology) is that you can actually be more faithful to the mono. ... The film was in mono, and I found it weird that we would be listening to the Beatles talk, and have it all come out of the center channel, but then the band would play, and the music would come out of the left and right speakers."
The restored version expands some of the sonic elements but keeps the Beatles' voices at center stage. "It makes for a more immersive environment," Martin says. He also notes that on the DVD and Blu-ray home video versions released three weeks ago, viewers have the option of choosing between a monaural audio mix or the 5.1 surround version.
The discs also include bonus features -- the documentary "Things They Said Today" and a commentary track drawn from interviews conducted by Beatles expert Martin Lewis for the 2002 DVD release of "A Hard Day's Night."
The film itself "has never looked this good in theaters," says Criterion Collection President Peter Becker, because "the prints made in 1964 were two or three generations away from the original 35-mm negative."
"When you're working on the Beatles, it's really a double-edged sword," says Lee Kline, who headed the Criterion film-restoration team that located the best existing sections to sub for the missing original negative in the restoration.
"You're working with things so many people are excited about, and something that's very important to people's hearts," Kline says. "You can't talk to Beatles fans without some of them overwhelming you with how excited they are, and you take that into consideration."
The business of putting pop-music performers on the big screen was spotty before the Beatles came along. The earlier movies often put the musicians in awkward settings, and the directors often had no feel for the exuberant energy of rock music.
Richard Lester, director of "A Hard Day's Night," and screenwriter Alun Owen avoided those pitfalls by channeling the Beatles' personal charm and sense of humor into the script, and allowing John Lennon, Paul McCartney, George Harrison and Ringo Starr to improvise many of their lines.
"In this case, the fifth Beatle was Richard Lester," Becker says, referring to the 82-year-old director, who has given his approval to the new restoration. "They trusted him, from his work with Peter Sellers and Spike Milligan and the Goons, which they totally loved. The level of freedom you feel in the film -- a lot of that is from some of the things Lester introduced."
Becker says he hopes the wide theatrical release of "A Hard Day's Night" will echo the shared international experience the initial release of the film created.
"There are ways to mess up a restoration," he says. "You can overproduce things, and overprocess them to where they start to lose their shimmer, lose their grace, lose their energy. For this film, that would have been a complete tragedy.
"This is all about life and liberation and freedom," Becker adds. "The Beatles are constantly breaking out of rooms; they are uncontainable in every way, which is how they were in life.
"Much of the humor in the film comes from people trying to get them to stay where they're supposed to be, and they're always running away to where they're not supposed to go," Becker says. "That freedom and freshness have to be there."