Aging Acetate Microfilm

Across my desk comes a reminder of a growing problem. Aging acetate microfilm.

Prior to the early 1980’s, most microfilm used for preserving newspapers, documents and even movie film, was made with cellulose triacetate. “Acetate” as it is commonly known became the standard from the 1930’s to the late 1970’s when production ended. No one really had taken into account various methods of storage and handling, thus resulting in a wide-spread deterioration of all acetate-based microfilm.
This has resulted in a big problem.

In our industry many libraries, historical societies and others, have much of their preserved history on this material. This presents a financial problem as well as the risk of losing the historical information forever if acetate deteriorates further. So do you have acetate microfilm in your collection?

The first thing we must do is identifiy the material. The best way to begin is to look back at your records and see how much of your collection has been purchased prior to 1980 or so. If you bought reels prior to 1980, there is a good chance it is acetate. Film purchased after 1980 is likely current-day polyester based microfilm. There are other methods of acetate detection.

Hold your reel of film up to the light. If it is acetate, as you look through from the side of the reel, it will be opaque, or light will not easily pass through it. Acetate also had tendencies to curl across the width of the film. There are other scientific chemical tests one may do on their film, but they are usually very expensive and cost prohibitive.  So if you detect acetate and it is deteriorating, what do you do?

The first thing that can be done is move it physically to a different environment to hopefully retard further deterioration and damage. Store it in a cool and low humidty environment. Ideally below 50 degrees and humidity at 20%. Keep in mind that will only SLOW the deterioration.

The best long-term way to deal with this problem is to refilm. If originals are still available, it is advisable to refilm onto polyester microfilm and create a new master copy. Since most institutions and organizations destroy the origial hard-copy material, or it is simply not available, the only realistic method to move that historical or preserved information is to make a duplicate or “dupe.” This is assuming that the film has not deteriorated significantly.

Using a silver-negative film ensures the best quality and allows that information to be saved for future use.

So take a look at your material, be proactive to it’s demise and save your historical information properly. Let’s make it last for another 500 years.