Recently I was given the opportunity to attend training on mould prevention in libraries. Having previously done some work experience in an archive’s conservation department, this subject particularly interests me. Mould can be one of the worst dangers for libraries, and a terrible threat to the special collections of which Oxford has so many. Here are five things that I came away with from this information session:
1. There are two types of mould – inactive and active. Active mould is the worst kind, capable of spreading and causing decay. It can be identified by its fluffy damp qualities. The other type is inactive mould, which is only slightly less of a problem, in that it can become active under the right conditions. Unlike active mould, you can spot inactive mould by its flaky powdery appearance.
2. Different types of mould react to different stimuli. We were warned that it was a fallacy to believe collections would be safe if the relative humidity of the room was kept below 60-70%, which is generally recognized to be a safe limit. Librarians need to make vigilant checks, in order to ensure they don’t have a mould problem even if they are following best practice.
3. Mould is pretty disgusting on its own. But once present, it invites pests that feed on it to the party. Eek!
4. Organic materials found in nature (paper, leather, linen and vegetable and animal glues) are a lot more susceptible to mould than synthetic materials. This is why books with covers that have been synthetically treated (chrome tanned leather for example) will have a bit more protection.
4. It is very difficult and costly to destroy mould and save what it has infected. Gamma radiation is one of the only ways to totally kill mould (which is very impractical and expensive to use), while other forces such as chemicals, or treatment in a fume cupboard, can only help to slow it down and make it static. This is why preventative care is so important, as once you have a problem it can easily become a nightmare!