Most movie theaters go to great lengths to tell patrons to keep their cell phones off and their comments to themselves. But when the Library of Congress screens films, they want the audience to bring along their laptops and tablets, chat with one another and yell comments so that everyone can hear. At least they do during the "Mostly Lost" Silent-Film Identification Workshop, essentially a film festival for movie-history buffs, which will be taking place for the fifth year at the Library of Congress’ Packard Campus for Audio-Visual Conservation in Culpeper, Virginia, from June 16 to 18.

The two-day event is crowdsourcing at its best, bringing together academics and members of the public interested in silent films. The Library will be screening a slate of five to ten film clips despite not knowing the titles or key information about them. The hope is that someone in the audience will be more familiar and be able to identify an actress, a filming location or a plotline that will help conservationists correctly identify the movies.

Biographies, film buffs and IMDB have seemingly catalogued every bit of minutiae of Hollywood history for decades. But the silent film era has been badly neglected. According to a report issued by the Library of Congress in 2013 only 14 percent of the 10,919 silent films released by major studios between 1912 and 1929 still exist in their original format. Another 11 percent exist as poor-quality copies. The other 75 percent is missing, either gone for good or sitting in an archive unlabeled and unknown, its volatile cellulose nitrate film literally disintegrating away.

David Pierce, author of the report and founder of the Media History Digital Library, called attention to the importance of the silent film era to the history of cinema in the study. “The silent cinema was not a primitive style of filmmaking, waiting for better technology to appear, but an alternative form of storytelling, with artistic triumphs equivalent to or greater than those of the sound films that followed,” he says. “Few art forms emerged as quickly, came to an end as suddenly or vanished more completely than the silent film.”

Since the Library began hosting the Mostly Lost festival for five years running, Neda Ulaby at NPR reports that the crowd has able to provide invaluable tips that has led to identification of half the films shown at the first festival in 2011. When Ulaby attended in 2014, the crowd was able to identify a film as German because of the raccoon-like eye makeup used in the video, as well as placing a filming location in Alaska and correctly identified the name of a French comedy, Zigoto Gardien de Grand Magasin. At last year’s event, Los Angeles Times reporter Noah Bierman wrote that attendees were able to say a film came from the Thomas Edison Studio because of the font used on the caption placard.

This year, the unidentified films will come from the Library, as well as the Royal Film Archive of Belgium, George Eastman Museum, Lobster Film Archive and the Museum of Modern Art. The crowdsourcing sessions will be broken up with presentation on film preservation topics, like how to identify still photos from films and history lessons about notable characters from the silent era, including pioneering camerawoman and studio head Angela Murray Gibson. During the evenings of the three-day event, the Library will screen restored prints of silent films including “Bride’s Play,” a 1922 film starring William Randolph Hearst’s lover Marion Davies produced by his film company.

The fact that so many films are lost or undiscovered isn’t necessarily a doom and gloom scenario. In fact, for many film buffs it keeps the genre fresh and interesting. “It’s almost as if they’re still making new silent movies,” Pierce tells Ulaby. “Because there [are] always films you haven’t seen.”