Acetate-based microfilm has been a trusted storage medium for decades, originally marketed as safety film after replacing the much more volatile and flammable nitrate film. It has been used for everything from car blueprints to family history archives. However, as time passed, it was revealed that acetate film may not have been the stable medium it was thought to be, and could potentially be a ticking time bomb, putting collections and archives at risk.
The spark for this bomb is something known as vinegar syndrome. Named for its distinct smell resembling vinegar, left unchecked, this chemical decay affecting acetate-based microfilm can not only destroy microfilm but also spread quickly through your collection.
A Flawed Medium
This blog is a reminder to anyone still relying on film-based archives. If you hold older microfilm and want to preserve the information it contains, now is the time to act. With the right steps, including digitisation, you can protect your records before the damage becomes irreversible.
Why Does This Happen?
When acetate-based microfilm is stored at humid or warm temperatures, the acetate base begins to decay and creates acetic acid that eats away at the photo beneath. It is this acid that emits the vinegary smell. The film will also begin to warp and become brittle, beginning to curl and crack, creating something archivists call “channelling” (view in the image to the right). As well as this, you may see white deposits of film known to migrate to the surface and solidify into small, white, crystalline structures. This is referred to as ‘’snowflaking’’.
What It Means for Historic Archives
Now that we understand what vinegar syndrome is and the risks it poses to our historic archives, we need to discuss what to do moving forward. Fortunately, if your collection is more modern, then vinegar syndrome is not as much of a concern. This is because in the 1980s the base layer of all microfilms was changed from acetate to polyester. All the manufacturers made this change, although it took a full decade. However, from the mid-1920s until this point acetate was the most common base layer format. So, if you have microfilm from around this time it is important to take action and make sure your information stays preserved.
Identifying Your Film Base
Firstly, you will need to be able to establish whether the film is acetate-based or the much safer and modern polyester base. This could potentially be done by physically tearing a portion of the base. Acetate-based film will tear relatively easily, whereas polyester film will not. Of course, this is not very reliable and involves damaging what you are trying to preserve. If you have any doubt at all, our technical staff at Genus are always available to help and advise. We can use more advanced methods to determine the difference, such as polarisation tests and acid detection test strips. So don’t hesitate to contact us.
Preservation Options
If the collection is still in good condition, then all that may be required is moving it into safer storage. The “IPI Storage Guide for Acetate Film” is an excellent reference regarding this. On the other hand, if your microfilm is in poor condition and showing signs of vinegar syndrome, then Genus can offer a few solutions. One of the more popular services we provide is digitally capturing your microfilm collections and then using editing software to enhance and even retrieve information otherwise unreadable. After which we can provide new microfilm copies printed on a safer more stable brand-new polyester base, giving you not only a digital version with a much more streamlined access, but also an enhanced film copy with much more longevity. We also provide a more economical diazo copy film which has a shorter shelf life of about 50 years but is a more inexpensive option.
What to do now?
So, whatever the state of your current collection, do not hesitate to reach out to us, whether it is for our services or advice. We will build a solution around you.
For our microfilm scanning service click the link here
And if you wish to see advice and consulting click the link here
