A Hard Day's Night, Richard Lester's madcap Beatles film, has been so pervasively influential – on music videos, TV commercials, and of course other movie directors and editors – that today its innovations seem almost commonplace. This was not the case when the film premiered in London 50 years ago – on June 6, 1964, to be precise, in the full roiling ecstasy of Beatlemania. Then, the picture's electrifying jolt of pop energy was a fanfare for a new era, and it was soon embraced almost universally, even by critics who up until that point had resisted the Beatles' music. As Roger Ebert later recalled, "I started letting my hair grow while I was watching that movie." The new restoration of A Hard Day's Night, which opens today in 50 cities across the country, brings us as close to that long-vanished period as we're likely to come any time soon. Kurt Loder says it's an extraordinary feat of digital salvage, blowing away all the dust and grit and warps and scratches from the original camera negative (and two master prints) to restore the film's sumptuous grayscale and its crisp black-and-white gleam in ultra-high 4K resolution.