Preservation FAQs

Q: What does “acid-free paper” mean?

A: Acid-free paper means that at the point of manufacture, the paper had a pH of 7 (neutral) or slightly above 7 (alkaline). A paper that is labeled “acid-free” with no other qualifier means the paper is currently acid-free but will probably become acidic over time. This definition applies to paper made from wood pulp. If paper is made from cotton, linen, or hemp, the longevity of the paper greatly increases.

Q: What does “lignin-free paper” mean?

A: Lignin is found in wood pulp and is the substance that exacerbates acidity. Lignin can be removed in the pulping process. It is expensive, but the resulting paper will remain acid-free much longer than wood pulp paper in which lignin is present. When newspaper turns brown over time, this is due to the lignin causing acid to form within the paper fibers.

Q: What does “buffered paper” mean?

A: Buffered paper means that a buffering agent, usually calcium carbonate, has been added to the paper pulp in order to neutralize any acids formed in the paper over time. Paper that has had the lignin removed is the most likely candidate to also have a buffering agent added. This type of paper has very good longevity.

Q: How can mold be eliminated from a collection?

A: Mold is impossible to completely eliminate from any area, as mold spores are in the air at all times. However, most molds that feed on cellulosic materials such as books and manuscripts are only active when the relative humidity climbs above 65-70%. High temperatures (above 72°F) also exacerbate mold growth. When a collection experiences mold growth, it is a sign that environmental conditions are inappropriate and must be altered. Once the environment is brought back to acceptable standards (relative humidity between 50-55% and temperature 68-70°F), mold will become inactive.

If mold is found in a collection, the materials should be isolated from other collection materials, as mold spores travel through the air and can infect “clean” materials. Once the mold has been made inactive, the item can be cleaned (you may need to consult a conservator for this) and the shelf cleaned before replacing the volume. Keeping a collection clean and within acceptable environmental standards will prevent most mold outbreaks.

Q: What is a good storage environment?

A: A good storage environment means that temperature and relative humidity are kept within the recommended limits (relative humidity between 50-55% and temperature 68-70°F), lights are kept off when not needed, fragile items are stored in boxes or drawers with appropriate support, no pests are found in the collection, and air circulation is good. A good storage environment acts as a preventative measure to reduce the need for more invasive procedures to preserve the collection.

Q: How can books be protected?

A: The best way to protect books is to store them in optimal environmental conditions: (relative humidity between 50-55% and temperature 68-70°F) and minimal light. Do not store books in attics, garages, or basements, as these areas typically have large temperature fluctuations, high relative humidity, and pest infestations. If books show signs of wear and deterioration, consult a conservator to find out the cost of having the book conserved.

Q: What can I do if my books get wet?

A: It is most important to get wet books dry as soon as possible. For small numbers of wet books, spread them out on a table in a room with good air circulation. If the books are hardback and can withstand it, stand them up and fan out the pages to get as much air circulation around them as possible. If the items are pamphlets or too weak to stand up, interleave the pages with white paper towels and open them up to dry. You may need to change out the paper towels and turn the pages every so often to allow all pages to dry. Fans help circulate the air, but should be kept on the floor and not directed at the books. This will prevent mold spores from being aggressively spread if any are present.

If you are unable to attend to wet books immediately, you may put them in plastic bags and place them in a freezer. Place only 2-3 books per bag so the cold can penetrate quickly. This will not dry them out, but it will stop any mold from growing until you are able to deal with them or take them to a professional to have dried.

Q: I have a book and would like to get is restored. How much will this cost?

A: The cost of having conservation or restoration work done varies a great deal. The cost will depend on the extent of damage and how much work you want done. Conservation or restoration work can vary from $100 - $1000 per book. The person you select to do the work will have to examine the book before knowing what the cost will be.

Q: I have a book with acidic pages that keep breaking when I touch them. What would be the best way to make the book usable again?

A: Acidic paper is a huge problem in the book world. There are a few ways to deal with acidic paper and some of the options cost more than others. The cheapest option is to make a preservation photocopy of the book and use it instead of the original. The original could be stored in a box for protection, but it will continue to degrade. Another option is to have the book treated by a trained conservator to deacidify the pages. One method of deacidification involves spraying each page with Bookkeeper, a product that will begin to neutralize acids in the paper. Another more costly option is to have the book disbound, washed, deacidified, and a buffer imparted to the paper. This process removes much of the built up acid and the buffer will remain in the paper fibers to neutralize acids that try to form later. One last option is to have the book disbound and each page encapsulated in polyester and rebound. The polyester will provide support while handling the book. Pages can be deacidified in this process as well, or a thin piece of buffered tissue may be inserted between each page to counteract acidity. Sometimes, paper has become so brittle that virtually no treatment is possible. If you think your book has reached this point, consult with a conservator for an opinion.

Q: I have a lot of old books. Are they valuable?

A: The only people qualified to answer this question are certified appraisers. They will have to examine the books in order to determine value. For more information on old books and appraisals, follow the link to “Your Old Books” on the Rare Books and Manuscripts web page at: http://www.rbms.nd.edu.

Q: How do i care for my library\'s audiotape or videotape collection?

A: Videotape has a short lifespan. However, good care and handling can extend its lifespan considerably. Storing it in a clean, controlled environment will slow down chemical deterioration. For long-term storage, the optimum environment is 45°-50° F and 25-30% RH, with a maximum fluctuation of ±2° and ±5% RH. Do not store videotapes below 45°F. When storing at low temperatures, be sure to acclimate the materials to room temperature before playing them back.

Store tapes in closed polypropylene or polyethylene containers to keep dust from getting into the tapes. Shelve tapes vertically, away from heat sources such as windows and computer equipment and magnetic fields such as loudspeakers.

Do not rewind tapes after playback. Instead, fast forward to the end of the tape after playing, and return the tape to its case. Do not leave tapes in a player for a long period of time, as this promotes poor tape pack and tape stress. Avoid using the pause button, as pauses of longer than 5 seconds will stretch the tape. Always eject the tape at the end of a recording to lessen any damage to the information contained on the tape.

Q: What are some good online resources for learning more about preservation topics?

A: Many libraries and organizations bave created helpful web pages covering the full range of preservation activities. Most of them are linked to Conservation Online (COOL), which is located at http://palimpsest.stanford.edu

Q: What kinds of repair and storage materials are appropriate for use with library collections?

A: Supplies for library collections should be acid free, chemically stable, sturdy, and non-damaging to library materials. Select storage folders that are acid free at the time of manufacture. Lignin-free materials will remain non-acidic for longer than materials that contain lignin. Buffered materials may be appropriate for storing paper materials such as newspaper clippings, but should be avoided for photographs as the buffering agents may cause deterioration. The only appropriate plastics to use are polyester (Mylar), polypropylene, and polyethylene. Never use polyvinyl chloride (PVC) because it is extremely unstable and gives off harmful acids as it deteriorates. Acceptable adhesives include polyvinyl acetate (PVA), wheat starch paste, and methylcellulose. Never use Elmer\'s Glue or rubber cement.