An acid free solution for Vinegar Syndrome
What is the collection?
Within the Documentary Heritage collection at Auckland Museum is a collection of over 60,000 photographic negatives which belonged to industrial photographer, Barry McKay. The negatives were housed in acidic storage and overtime the collection has deteriorated.
Why have the negatives deteriorated?
The negatives have experienced acetate film base degradation, also known as ‘vinegar syndrome’. The chemical make-up of the plastic causes them to degrade, and this degradation is vastly dependent on storage conditions. Vinegar syndrome results in a rather pungent vinegar-like odour and is followed by embrittlement, shrinkage and warping in the negatives. The higher the temperature and humidity of the storage conditions, the faster the onset of degradation.
What can we do?
This is where the Collection Care team comes in; I have been working alongside a team of three volunteers, Hannah Fotheringham, Heike Eichenberg and Alicia Taylor to rehouse the negatives into more suitable storage. When new objects are re-housed it is important to mitigate potential harms to the collection such as pests, dust and light, and to ensure the new housing is accessible and appropriate for long-term storage.
To re-house the photographic negatives, we transfer a portion of them to the Conservation Lab and work underneath a fume hood - this limits our exposure to the fumes from the negatives and also helps us to escape the smell! One by one each negative is removed from its original storage and carefully transferred to an acid free envelope.
Barry McKay created his own numbering system for the negatives which he recorded on the original envelopes and to ensure information isn't lost, we are transcribing this information as well as client names, dates and any other notes onto the new acid free envelopes. The information is then logged onto a spread sheet with details of where each negative is stored to allow us to easily locate them. Following this, the envelopes are sorted into numerical order and grouped in larger acid free boxes.
The process of rehousing, recording and sorting 60,000+ negatives is quite extensive and the help offered by the volunteers is invaluable. Hannah, Heike and Alicia dedicate one day a week to coming to the museum and contributing to this project - we simply couldn't do this kind of work without them!
What's next for the collection?
The most effective method to prevent deterioration in photographic negatives is to store them in cold, moderately dry conditions. At the new storage facility the negatives will be kept in cool storage; around 1-2 degrees for the acetate film negatives and 12 degrees for the glass plate negatives. They will also be stored separately from the non-degrading film to prevent the spread of the vinegar syndrome.
Post by: Georgia Brockhurst
Georgia is a Collection Manager, Collection Care at Auckland Museum and works in preventive conservation.