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Safety film has since been replaced by polyester film, which can last upwards of 500 years.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.