His comment hints at the true importance of this project -- building an accessible library of films that can give viewers an understanding of movie history.

Through the painstaking monotony of their task, Wang and his colleagues have accumulated a wealth of knowledge about Chinese films and grown to appreciate these cinematic works.

"We restored an animation in 2012, 'Rat and Frog', which was produced in 1931," he recalls. "The techniques and production standards were on par with the Walt Disney Company -- so it's hard to say who might have influenced whom."

Wang complains that younger restorers, though technically accomplished, lack understanding of old Chinese films, and the social and historical context.

"All the movies, once restored, must be evaluated by experts and directors," he says, noting that historical know-how is especially important to the work of CFA counterpart the Central Studio of News Reels Production, which works to restore vintage Chinese documentaries.

The CFA's digital library holds more than 30,000 Chinese feature films and 600,000 copies of works produced since 1922.

Li Tao, deputy head of the CFA's public affairs division, explains that the restorers prioritize badly damaged films with high historical value: "We are not willing to see these precious archives disappear."

The CFA has digitally restored some 7,000 films, including the earliest existing feature-length Chinese movie, "Labor's Love".

Despite the success, the CFA faces challenges. It receives annual government funding of 35 million yuan (about 5.6 million U.S. dollars), but still needs more donor assistance.

"It's common practice internationally for film restoration work to get financial support from production companies or nongovernmental bodies as it's considered a public service," according to Li. "In China, we need to attract more private capital into film preservation."

The CFA is also short of skilled technicians. "The intensive and tiring nature of the work keeps many young engineers away," he says.

"A good film restorer should have understanding of the film's chemical and physical nature, be skilled at using computer software, and know Chinese film history -- not many people have all that."

His summary of the job may be the biggest recruitment draw. "Legends survive on film. What we do is keep legends alive."