Preventing "vinegar syndrome" - the catalytic chemical reaction that occurs when cellulose triacetate-based motion picture film begins to break down, releasing acetic acid - is a key challenge faced by film archivists.

Traditionally, archivists have controlled vinegar syndrome in two ways. First, they keep film cold and dry. Second, they isolate film that has begun to deteriorate so it doesn't trigger the reaction in neighboring reels. As a last resort, archivists also may transfer the photographic record to a new master film.

Archivists now have a powerful new tool: zeolite molecular sieve technology. Molecular sieves scavenge acids, moisture, oxidants and solvents that are generated by stored acetate, polyester and nitrate films. This prevents those chemicals from further reacting with the film, which in turn helps to slow the degradation process.

One film archive that uses this technology to protect its holdings is the International Museum of Photography and Film at the George Eastman House in Rochester, New York.

The Eastman House holds one of the largest motion picture film collections in the United States. Its 20,000-odd titles include "classic Hollywood" -era films from MGM and Warner Brothers Studios as well as extensive collections of documentary, independent and avant garde films, and early American silent movies. The museum also houses private collections, including over 5,000 titles belonging to Martin Scorsese.

The museum stores its collections at two facilities. Its nitrate collection - the fourth largest in the United States - is kept in a facility, The Louis B Mayer Conservation Center, opened last year on 3 1/2 acres in the Rochester suburb of Chili. The acetate collection is stored at the museum. That eight-year-old facility includes three vaults, plus a staging area where films being moved to or from storage are conditioned.

Edward E. Stratmann, assistant curator of film collections for the museum, explains that housing films in a museum is different than caring for newer, more homogeneous collections. Among the Eastman House films are prints that date to 1895. The condition of films in the collection vary greatly. "We have 100-year old films that are in perfect condition," Stratmann says, "and films from the 1940s in much poorer condition."

To further complicate the task, films donated to the collection often have uncertain origins. "When we create prints ourselves for preservation purposes, we know their history," Stratmann explains, "but we may not know how films donated to us have been stored. We still get people coming in off the street, believe it or not, saying 'my father died and this was in the basement next to the furnace.' Just a few years ago, somebody walked up to the receptionist at front desk of the museum. She was busy with other visitors, so he handed her a bag, and left. When we opened the bag, we discovered a nitrate print of The Great Train Robbery."

That donated print was actually in better shape than the one already in the Eastman House collection, but that is not always the case, Stratmann observes. When films that were stored improperly in the past are donated, the museum risks endangering the rest of its collection. Careful monitoring of the collection is Stratmann's first line of defense.

"Once a year, we inspect the collection," Stratmann says. If the presence of acetic acid is noted, either by smell or testing, that reel is flagged on the museum's computer for special attention. That attention includes placing molecular sieve pouches in the film canister. Stratmann views the molecular sieves as a complementary strategy to controlling storage conditions on a macro level.

"Molecular sieves help control the micro-environment - the conditions in the can," Stratmann says. "They don't replace proper storage conditions, but they are one more way to fight vinegar syndrome."

After "treating" problem reels with molecular sieve pouches for a period of several weeks, Stratmann's staff re-tests the film. This procedure has verified that molecular sieve technology does reduce the presence of degradation by-products. "Obviously, this practice can't restore film that has begun to deteriorate," says Stratmann, "but it can slow the reaction down significantly, giving us time to make a copy of the film, if necessary."

The Eastman House also puts sieves in all newly acquired films, to protect them and to ensure the safety of the rest of the collection.

"Ever since vinegar syndrome was discovered, archives have been looking for some kind of an answer," says Stratmann. "While research is still going on as to the cause, we do know that once the reaction has begun it will continue even if you do control the storage environment."

Molecular sieves, he says, give his facility a new way to slow that reaction and protect its archives. "We're proud to have films in our collection that have passed the 100 year mark," he concludes. "Molecular sieve technology is one more tool we can use to maintain our preservation standards."

For information about purchasing molecular sieves, please call 1-800-621-3456 within the US. Outside the US, call FPC, Inc. at 213-468-5774, fax 213-468-5771 or write to FPC at 6677 Santa Monica Blvd., Hollywood, California 90038.