There is nothing quite like the smell of a brand-new book. The crisp pages and the new ink can send the senses reeling. Some archivists and librarians would also say there is nothing like the smell of older books as well, though taking a deep breath of the old stock might bring on the coughing and wheezing associated with the accompanying layer of dust. But what happens when walking through the stacks you take a deep breath and – uh oh – that’s not supposed to smell like that!
In the best of circumstances, archivists can control the environment in which documents are kept. However, there is still a degree of natural decay that different record mediums go through over their lifetime. In particular, when laminate and microfilm deteriorate they produce a strong vinegar or ammonia odor, called vinegar syndrome. Unfortunately, once vinegar syndrome starts, it cannot be stopped and any nearby collections are at risk as the off-gassing process may cause stable records to begin deteriorating.
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| This laminated document is part of a 1837 petition. The translucent lamination material is visible around the edge of the document and in the gap by signature fifteen. Record Group 60. Tennessee State Library and Archives |
Lamination as a means of stabilizing, repairing, and strengthening papers on a large scale was popular from the 1930s through the 1970s. The process involved deacidifying a document, layering it between tissue and thin sheets of plastic, and fusing them together in a heated process. [WARNING! Do not laminate your precious records! You would not use heat or tape to preserve your records, so why laminate them?] The most popular laminate, cellulose acetate, does its job in the short term – it strengthens the records it encapsulates. However, it is also inherently unstable and causes irreparable damage to the record. Cellulose acetate decomposes through a chemical reaction that causes the bonds of the cellulose acetate molecule to break down and release acetic acid (signified by the vinegar odor). Not only does lamination warp documents with heat and chemical decay, it could exacerbate the problems the process was meant to fix. If those issues are not reason enough, the long-term deterioration of laminate further puts documents at risk. Remember, lamination drives the laminate material into the paper document, and as the laminate breaks down, the document will suffer.
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| Microfilm suffering from vinegar syndrome, Tennessee State Library and Archives. |
Microfilm went through several phases of material, including acetate (popular from the 1920s to the 1980s). Acetate microfilm goes through a degradation process similar to lamination, producing the vinegar or ammonia odor. As with lamination, there is no way to stop the deterioration of acetate microfilm once it starts. However, acetate microfilm has a “shelf life” of approximately 100 years, meaning there is time to replicate the film before its images are completely lost. Most replicas are transferred to the more stable polyester film. Polyester microfilm gained popularity beginning in the 1970s and continues to be the standard. It is exceptionally stable and has a life expectancy of 500 years, with proper environment and treatment.
If vinegar syndrome is irreversible, what can you do to protect your collection?
- First, monitor and improve (if needed) the storage environment. Deterioration can be moderately slowed (not reversed) in an environment that is dry and cool.
- Second, keep watch! All acetate film and cellulose acetate laminate are subject to deterioration. Watch for discoloration or possibly obtain acid-detection tests that will change color when acetic acid is released. And of course, be mindful and take action when you smell that vinegar.
- Third, quarantine infected items – vinegar syndrome spreads!
- Finally, duplicate items to retain a copy of the records when the original eventually deteriorates.
Further reading:
“Guidelines for the Care of Works on Paper with Cellulose Acetate Lamination,” Artwork Preservation Project, Department of Anthropology, National Museum of Natural History, Smithsonian Institution, https://anthropology.si.edu/conservation/lamination/.
Mary Lynn Ritzenthaler, Preserving Archives and Manuscripts (2nd ed.), (Society of American Archivists: Archives Fundamentals II Series).
The Tennessee State Library and Archives is a division of the Office of Tennessee Secretary of State Tre Hargett
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