Gosford Micrographics offers to firms a Microfilm Integrity Test & Audit Service. Contact Gosford Micrographics and we will evaluate your archival microfilm library, and put forward an immediate solution. Film produced between the 1940s and early 1980s used cellulose acetate as its film base, replacing nitrate. At the time, the acetate film was called “safety film” because it was comparatively more stable and less flammable than its predecessor. Acetate was used as a film base almost exclusively until the early 1980’s, when it was replaced by stable polyester.
Regrettably acetate is not chemically stable and will deteriorate under normal conditions, slowly at first and then with accelerated speed (with a vinegar-like smell in the final stages). The legacy of acetate is large parts of film collections exist on an unstable film base, and this is a serious concern. The accepted method to slow the deterioration rate is cold storage (5–10°C at 20–30% humidity) — this buys time to assess more interventional options such as duplicating, scanning or re-filming. However, there is not much time left to take urgent action when the film is in the “vinegar state”. Should a library inadvertently wait too long the film layer carrying the optical information will tear and split off from the film base.
What happens at normal room temperature:
In average room storage conditions—in the presence of moisture, heat and acids— the cellulose acetate base can break down. The chemicals combine with water to form acetic acid, the compound that gives vinegar its familiar taste and odour. The result:
The film base loses its dimensional stability and becomes brittle. The microfilm may curl, shrink and buckle, degrading or destroying the preserved images.
The good-news is that film produced after the mid-1980s is not prone to vinegar syndrome though some manufacturers did not stop production of the triacetate film until 1994. That’s when film manufacturers began migrating to a rugged polyester plastic base. These polyester microfilms have a minimum life expectancy of 500 years when properly processed and stored.
Vinegar syndrome is usually the sign that there is something catastrophic happening. It’s a clear sign that your vital microfilm records are in danger.