Vinegar syndrome
Last month staff at the Archives discovered that some of our photograph collections are in danger. We learned that some images — negatives and prints — from the 1950s were being affected by vinegar syndrome. This was discovered when a box of negatives was brought from storage for a researcher. When opened, we smelled a strong odour of vinegar.
Negatives with cellulose triacetate supports break down over time, sometimes at an alarming rate. This format was common from the 1930s to the 1950s. When the damage becomes severe, acetic acid, the main component of vinegar, is formed.
The smell is not the only problem. This deterioration causes the plastic base of the film to shrink and buckle, making the emulsion, the part of the photograph that holds the image, crack. This can destroy the image. To add to the problem, this syndrome is contagious. Like dominoes, as one negative begins to break down, acetic acid affects others nearby and causes the process to begin there as well.
As soon as we knew some of our negatives were in danger, we devised a plan to save as many photographs as possible. We also wanted to save our intact photographs from a similar fate.
Because the syndrome is contagious, we looked at all of the surrounding materials. At least 2,000 images are impacted. We isolated these so that the problem will hopefully not spread. We are also testing our other negatives.
We aim to scan as many of the images as we can before it’s too late. By scanning at least a sample of the images (for example, two views of a wedding party), staff and researchers can continue to access images even when the negatives are frozen. Freezing is the only way to slow vinegar syndrome down enough to save the photographs for future generations.
Freezing negatives is not as simple as piling boxes from shelves into freezers. Each negative needs to be put in an acid-free envelope, then placed in an air-tight plastic bag with specially-treated mat board to absorb any condensation so ice crystals do not form. The negatives are then slowly frozen over 24 hours and are kept at temperatures well below freezing.
By identifying the negatives most at risk and getting them scanned and frozen, we hope to preserve these records of our community for years to come while keeping them accessible to you.
Philip Pype is Archivist at the Esplanade.