Mold and Paper
Paper, when exposed to the wrong conditions, can become an optimal breeding ground for mold. Here, learn the basics about the hazards of mold on paper, how to prevent mold growth, and what to do if you find mold on your paper art or documents.
The Hazards of Mold
Mold is not only a health hazard to humans and pets, but it is damaging to organic materials like paper. The enzymes excreted by mold can cause permanent staining, paper loss, paper weakening, odors, and, eventually, paper decomposition. Because mold spreads by airborne spores, the risk of an outbreak of mold on a large scale is the most concerning problem.
The most significant factor for the growth of mold is moisture. High levels of relative humidity will cause mold spores to germinate, and mold requires a moist environment to grow. After moisture, temperature is the greatest factor, as mold flourishes in temperatures ranging between 59 to 95°F. Keeping your paper documents and art in dry, cool environments with good air flow will help prevent mold growth. Avoid storage in closets, basements, bathrooms, or the outside walls of a house. If you have a large collection, consider investing in a dehumidifier.
Archival framing also plays a part in the prevention of mold. Archival framing begins with the use of a sturdy frame with solid corners and an opening large enough to prevent contact with the edges of paper. UV filtering glass or Plexi glazing is added to the frame to protect the surface of paper items from exposure to mold spores and UV rays. An acid-free window mat or a set of spacers is used to prevent the item from coming in contact with the glazing, thus eliminating the risk of adhesion of artist’s media or the formation of pockets of moisture and resultant mold. For items that have previously been affected by mold, the recommended distance from the glazing is 3/4”. Additional acid-free backing material is added if possible, and the frame is sealed with a dustcover applied to the reverse.
If your paper art or document collection has suffered from a mold outbreak, measures should be taken relatively quickly to prevent the spread and damage from the mold. Humidity should be reduced to below 60% as soon as possible, and the storage area should not be heated. If the items are still wet or it is not possible to reduce the relative humidity quickly enough, it is recommended to freeze them. This will kill the active mold and prevent the spread of spores until the items can be treated. Please also keep in mind that there are health risks involved with mold exposure.
After controlling the storage environment of your affected items, contact a professional conservator or restoration service to remove active mold or reduce the appearance of damage from mold.
Mold outbreak? Water damage? See our page on collection disaster recovery here.
American Institute of Conservation, “Mold/Fungi”: http://cool.conservation-us.org/coolaic/sg/bpg/pcc/12_mold-fungi.pdf
NEDCC, “Emergency Salvage of Moldy Books and Paper:” https://www.nedcc.org/free-resources/preservation-leaflets/3.-emergency-management/3.8-emergency-salvage-of-moldy-books-and-paper
Connecting to Collections Care, “Mold!” webinar: https://www.connectingtocollections.org/moldrecording/