It’s every film buff’s fantasy: to stumble over some rusty cans of nitrate film in an inconspicuous location only to discover that they contain the only print in existence of a lost silent classic. The thing is, it actually happens every so often.

The result of one such recent find – the long-lost 1922 Rudolph Valentino and Gloria Swanson vehicle “Beyond the Rocks” – has resurfaced and will be shown in New York on Friday for the first time in nearly 80 years at Anthology Film Archives in the East Village.

Directed by Sam Wood and adapted from a 1906 novel by the once infamous Elinor Glyn, whose prose merits a more descriptive epithet than merely “purple” (“mauve” might be it), the film tells the story of the ill-starred romance between Theodora Fitzgerald (Swanson) and Lord Hector Bracondale (Valentino).

But the plot is just an excuse for some nice scenery, much of it obviously fake, and an exorbitant number of costume changes by the notorious clotheshorse Swanson – although Valentino more than holds his own in this regard. He also gets to save her life twice – once from drowning, once from falling off a cliff, which gives you an idea of what kind of film this is.

The charm of “Beyond the Rocks” is in witnessing the chemistry between two silent legends at the top of their game appearing in the same film (a rarity at the time – pairing stars didn’t become commonplace until the sound era). In fact, these two never made another film together.

To understand just how enormous a star Rudolph Valentino was in the 1920s, you have to see him on a big screen, and preferably in a nitrate print. A few years ago I was lucky enough to see the film that made him a star, Rex Ingram’s “The Four Horsemen of the Apocalypse,” at the Museum of Modern Art. When that first big close-up of Valentino hit the screen, several women in the audience audibly gasped – suddenly, I understood the hysteria that greeted his untimely death in 1926. Likewise, those who think of Gloria Swanson only as Norma Desmond in Billy Wilder’s “Sunset Boulevard” (1950) will see just how glamorous she could be in her prime.

How the film survived at all is a story as intriguing as the film itself. Swanson wrote in her autobiography that “Beyond the Rocks” was one of the films she was asked about most often, but for decades all that survived of it was a one-minute fragment.

The death of an eccentric Dutch film collector living in Haarlem, however, provided the Nederlands Filmmuseum with the opportunity to go through his massive collection – 2,000 cans of film in various stages of decay. The man had so little storage space that he’d been sleeping with rusty cans of flammable nitrate film piled up on either side of him (which makes about as much sense as sleeping in a bed with 27 sticks of dynamite).

The cans contained pieces of a film no one recognized, until they checked the name of the main character on the title cards and realized that it was the missing “Beyond the Rocks.” Restorers at the Nederlands Filmmuseum were able, by putting together pieces stashed in separate cans, to compile a nearly complete print of the film (a few minutes are still missing).

The film has been given a barely serviceable music score by Henny Vrienten, former lead singer of Doe Maar, the phenomenally successful 1980s Dutch pop group. The decision to “stretchprint” the film – in order to make it appear to run properly when projected at sound speed – is also unfortunate.

Nevertheless, this is a film every film lover should see – either at Anthology or on the new Milestone DVD.

Friday, Sunday through Thursday, 7 p.m. & 9 p.m.; Saturday, 5 p.m. & 7 p.m.