After attending a Care and Display of Archives workshop at the Natural History Museum, it seems timely to look at why preservation in Archives and Special Collections is so important, and what can happen if correct environmental controls and correct packaging are not adhered to.
Preservation: Ensuring that material will not be damaged in the future, by controlling external influences
Conservation: Treating material after it is damaged. Conservators must try to make sure that the treatment is reversible.
Causes of Deterioration
- Incorrect handling (the greatest cause!)
- Incorrect storage, including staples and paperclips which rust, and make the paper vulnerable
- Fluctuation of temperature and relative humidity, which causes material to expand and contract
- Heat – causes paper to be brittle
- Light – fading and discolouration
- Pests – including mice and woodworm, which cause holes and damage. Pests will be attracted by food and drink, and often the damp
- Humidity – high humidity causes mould and low humidity causes brittleness
- Acidity – high acidity comes from lignin present in wood, which breaks down the paper. Paper today is much more impure than earlier paper, which is far more likely to last the test of time.
- Foxing. Foxing are the brown spots that you can see on paper. This can be caused by the acidity of the paper, and outside conditions. As long as the material is readable this does not have to be removed.
- Iron gall ink – this ink causes degradation leading to browning. It is chemically unstable and can eat through paper. It was widely used in 20th century artwork
Ways to combat deterioration
- Following environmental condition recommendations (13C-20C and Humidity 35-60 RH)
- Acid free packaging
- Brass papers (which do not rust) and melinex(chemically stable and inert) sleeves
- Correct handling, including not leaning on the document and supporting the book by the spine
- Use of pencils only
- No food or drink
- Ensuring books are correctly supported by book rests, of ideally inert foam