LOS ANGELES (AFP).- In the Spanish colonial-style environs of Hollywood's Roosevelt Hotel, around 100 film buffs chew pencils, polish spectacles and furrow brows in the flickering glow of long-forgotten silent movies.
These cinema sleuths are being shown a selection of snippets from thousands of old films stored lovingly by the US Library of Congress -- despite no one having the foggiest idea what most of them are.
The library hosts annual "Mostly Lost" workshops at its Packard Campus in the foothills of Virginia's Blue Ridge Mountains, where scholars and plain old enthusiasts gather to find out as much as possible about the unknown, or little-known, films.
"The Library of Congress is intensely committed to investigating, identifying, preserving and making accessible our silent film heritage, so much of which is still unknown," said Greg Lukow, head of the national audiovisual conservation section.
The library has gone on the road to bring its work to the TCM Film Festival, a celebration of Golden Age Hollywood held every year in the spiritual home of American cinema.
Attendees quiz neighbors, consult databases on tablets and smartphones and shout out the names of actors, locations, car models and anything else they recognize as piano maestro Ben Model accompanies the clips.
"That's Balboa Park in San Diego!" yelled a middle-aged woman in a red baseball cap as one clip played. "There's a gas tank like that in east LA!" another added breathlessly.
These film buffs are relying on knowledge amassed over a lifetime, information that cannot simply be culled from the Internet Movie Database or crowdsourced on Twitter.
We're very proud'
"Anyone recognize that typewriter?" Library of Congress technician Rachel Del Gaudio asked hopefully, poised with pen and pad as those present scrutinized the grainy monochrome footage.
"Some attendees have a great knowledge of film history already but that's not required. Sometimes people just have a great memory for stories," Del Gaudio said.
"Maybe somebody happens to know that the film playing on screen is some forgotten-about tale from the 17th century. Or maybe you're a world class researcher. Maybe you're like one of our star attendees who easily recognizes faces. Or sometimes butts."
She's talking about Steve Massa, of the New York Public Library for the Performing Arts, a legend at "Mostly Lost" since he named a fat silent actor two years ago after seeing just a few frames of his backside.
The 45-acre (18-hectare) Packard Campus, about 75 miles (120 kilometers) southwest of Washington, houses 7.5 million films, TV and radio shows and other recordings, on more than 90 miles of shelving.
A little over half of the 763 clips shown since 2012 have been identified, in the workshops themselves and through further research.
"We're very proud of that. Some of those films exist elsewhere in more complete form, but with quite a few of those, that is literally the only known existing material of that title," Del Gaudio said.
A 2013 study for the Library of Congress showed three-quarters of nearly 11,000 silent films released by major studios between 1912 and 1929 have been lost.
Experts argue, however, that many were likely forgotten for a reason and, even if their identities are restored, would not be held up alongside "Ben-Hur," "The Gold Rush" or "The Ten Commandments."
Feature films -- stored in metal cans before digitization -- can consist of 150,000 frames or more, across numerous reels, any of which could be lost through nitrate deterioration, fires or floods.
Picture houses failing to return prints, poor handling, silent-era bootleggers and faulty projectors were among the hazards a studio would face trying to hang onto its beat-up movies.
Among the more high-profile gems uncovered by "Mostly Lost" are a 1928 Walt Disney cartoon, a 1933 Three Stooges color short, a 1927 comedy by John Ford and "The White Shadow," the earliest surviving film credit for Alfred Hitchcock.
A stolen baby mixup vignette screened at the Hollywood event -- recently revealed to be "Toodles, Tom and Trouble" -- is amusing enough but comes across in these less innocent times as kind of creepy.
Experts were able to narrow down its 1915 release date and New York location by the fashions of its actors, products in shop windows, an English-language newspaper, gas streetlamps, brickwork in a park and more.
In another clip, a long camera shot and painted scenery narrow down the era while in a third a calendar in the background shows the date May 28 falling on a Saturday, meaning the movie was most likely shot in 1921.
"We are fortunate that we have many, many non-film resources both in print and, now, online," said moving image curator Rob Stone, the originator of the workshops.
"It really has been a game changer for us with 'Mostly Lost,' once we got WiFi in our theater."
© Agence France-Presse