London library eyes digitization to rescue local history from deteriorating microfilm

The London Public Library is in a race against time to digitally save more than a century's worth of local history from a vinegary grave.

"The clock is ticking. Inevitably, this will all be an unusable mess of vinegar-soaked acetate," said David Caloren, the library's co-ordinator of central adult services.

Caloren was referring to the hundreds of reels that make up the library's microfilm collection, containing generations of reporting published in newspapers including the London Free Press, London Advertiser, and The Dawn of Tomorrow, dating back to the mid-1800s.

A majority of the collection is in the early stages of degradation, a result of the material the microfilm is made of — cellulose acetate.

Introduced in the early 20th century to replace highly-flammable nitrate film, cellulose acetate-based film, also known as safety film, was used for decades for photography, film production, and for microfilm.

While more stable than nitrate, it comes with its own problems including that it breaks down, a contagious process called acetic deterioration, or "vinegar syndrome" for the smell of the acetic acid it gives off.

Staff at the library first noticed an issue with the older microfilm in February, and tests of random reels with acid detection strips, or A-D strips, found it to be widespread.

Most of the reels are in the early stages of vinegar syndrome, however, some are actively degrading, necessitating they be stored in a freezer to slow the decay and keep them from impacting other reels.

For the rest, the library has closed the microfilm room and is running two air conditioning units inside – something that will slow, but not stop the process.

"They're still all usable. Thankfully, they don't have the brittleness or the buckling... But we know we have a closing window of time in which to do something about it," Caloren said.

"Maybe 5–10 years before we start noticing damaged reels that are breaking, strips that cannot be loaded or moved through the machines."

Heat and humidity hasten the onset of vinegar syndrome, causing the film to shrink and become brittle, with early detection and cold storage "the most effective defences," the U.S. National Film Preservation Foundation said.

Safety film has since been replaced by polyester film, which can last upwards of 500 years. Caloren says this is what makes up the microfilm received since the early 1980s.

With so much history at risk, the library is looking to digitize the collection, a process that will take time and resources. 

Sending the collection off to be scanned could cost upwards of $250,000, library officials said, and librarians and the broader public wouldn't be able to access the reels during that time.

Doing the work in-house is an option, but each roll takes about three to four hours to scan with the library's newer microfilm readers. It would also require at least one staff member, taking them away from other work.

"We've been gathering information about what our options are, and we'll have to make some decisions based on costing and time for staff and other issues," said Elizabeth Sutter, manager of community services and branch operations.

"I'm not sure we have the financial resources to ship it all out, so whether we make that decision for the more degraded materials... I'm hoping we'll have this decision made for the fall."

Caloren said he planned to begin scanning reels himself as soon as possible to get the ball rolling until a decision is made.

While much of the microfilm is public domain, some is under the copyright of Postmedia, Sutter says. In addition, Western University owns the copyright to several decades of the paper's photographs.

There are provisions in copyright law around preservation, but Caloren says things get murky in making that scanned microfilm accessible online.

The newspaper's former owner donated 1.6 million negatives spanning 1936 to 1992 to the university's archives between 1984 and 1997.

Tom Belton, head of archives and special collections at Western Libraries, said vinegar syndrome had been an issue with hundreds of negatives from the 1950s that were digitized by the university.

Scanning all of it would cost close to $4 million, he said.

"[The] cost of scanning, processing files, and associated digital preservation is challenging as we have limited capacity and funding to do much more than respond to user requests."

Up to 70,000 negatives have been digitized so far, carried out between 2013 and 2019. However, Belton said systemic digitization has been put on hold to focus on preserving already-digitized material.