-Contributed by Arlie Belliveau
After 24 grueling hours of waiting for the A-D test results, I finally got to open up the first set of film canisters! If the strip stays blue (a rating of 0-0.5), then the film is still in good condition. A green strip (a rating of 1-2) means that the film has begun to decay and is at risk (within 5 years) of warping, shrinking, and becoming brittle. A yellow strip (a rating of 2.5-3) means that there has likely already been irreversible decay, and the film requires immediate attention.
The first strip came back with an acidity rating of 1.5 (green). I had expected the 1934 film, titled “Decorticate Dog – Behavior and incidental CR”, to have that kind of result. However, to my surprise, when I opened the film canister for the 1929 Eastman Kodak educational film “Frequency Curves”, I saw that the strip had remained blue! With an acidity rating of only 0.5, this film is still quite viable.
So, I spent the last week testing a small sample of 100 16mm films for acetate decay. The films in my sample ranged in age from 36 to 91 years old, with an average age of 64 years. I was pleasantly surprised to find that most had an A-D test strip result of 0.5
Hoping to get a better understanding of the chemistry behind the process of acetate decay, I met with Polymer Science graduate student, Joey Scavuzzo, who specializes in Polymer Synthesis .
We discussed just what an acetate film was, and how it comes to generate acetic acid vapor. Apparently, film is a polymer (meaning a molecule made up of a long chain of chemical bonds)! Most of the bonds in that chain are strong; however, when they come into contact with heat and water (for example), the bonds holding the acetate gas side groups can break down. It is when those molecules break free that the film properties change (warping, shrinking, breaking).
“So why don’t we just store all the films into the break room freezer?” I asked. Well, that would be good and fine, he replied, so long as we could control the relative humidity of the freezer, and so long as we never opened the door. He explained that the cooler air in the freezer would have lower humidity than the air outside. And so, just like in the wintertime when you walk inside with your glasses on, water from the more humid room would condense onto the surface of the films. This, of course, would just accelerate the acetate decay.
After a very informative afternoon, I thanked Mr. Scavuzzo for his help and asked if he had anything that he would like to tell my readers about his experience with the film collection. Without skipping a beat he stated, “It’s good, and I hope it lasts forever!”
My cleaning and preservation supplies should be arriving early next week. And once I put some of the elasticity back into the films, flatten out any warping, splice up any tears, and add some leader tape, I might actually get to watch (and digitize) some of these delicate artifacts from psychology’s past.