Connecticut State Library with state seal

Preservation Office

Preservation Advice for Libraries, Historical Societies and Home Collections:
Taking Care


The oldest paper, up to about 1870, was made from rags and is very durable. From about 1870-1990, paper is most likely made with wood fibers and is likely to deteriorate. Since 1990 a different manufacturing process uses wood fibers but makes paper that is more durable. However, recent efforts to increase the recycled content of paper may reduce the durability of modern paper. Whether made on rag paper or wood pulp paper, the minimum you should do is:

More information:

Conservation/Preservation Information for the General Public from Conservation OnLine (CoOL)

The Library of Congress Preservation "Collection Care" site has publications on preserving "Works on Paper", "Newspapers," and Care, Storage and Handling of "Books" and so on.

Resources for private and family collections by NEDCC

Preservation leaflets by Northeast Document Conservation Center (NEDCC)


Once a leather binding has deteriorated to the red dusty stage, called red rot, there is nothing that can save the original leather. The best solution here may be to put a polyester dust jacket on the cover to protect you and the adjacent books from getting covered with the red dust. If a leather cover is in the early stages of red rot a proper storage environment can increase its longevity.

Get advice from a conservator before using leather dressings, which you may find listed in the archival supplies catalogs.

More information:

I have some old leather books with dried and cracked bindings - should I put leather dressing on them? from NEDCC.

Leather Dressings from the Library of Congress


There are no guarantees and the recommended method takes a long time to work. We once used baking soda, following the method described in the NEDCC pamphlet, and after a month the odor was lessened but still detectable. Be patient. Once the odor is removed or diminished, keep the book in the best environment available. Exposure to moist air can trigger another growth of the mold which may have caused the odor in the first place. Avoid ozone, which is used in commercial operations to remove odor, because it can damage books and paper.

More information:

How can I remove the musty smell from old books? from the Northeast Document Conservation Center


Blueprints and some art photographs with blue images are Cyanotypes. Cyanotypes are made from a chemical called Prussian Blue, which is sensitive to fading when exposed to light and can be washed away if it gets wet. Also, because Prussian Blue is sensitive to an alkaline environment, the paper can not be treated to become less acidic, and so, in time, will become brittle. If a blueprint or other cyanotype will be heavily used or is heavily deteriorated, and there are no copyright considerations, consider making a use copy. Just be careful when exposing it to light during the photography stage. Store cyanotypes:

· In an area with low humidity and good ventilation. Do not encapsulate. Free air helps to maintain the image while helping to remove the acids that attack the paper.

· In the dark. The chemical impurities that cause fading won't go away but a faded cyanotype might be restored if put back in a dark, airy, well-humidified environment for 5 days and then move it to a dark, airy, drier environment.

· Flat. The natural acids in the Prussian Blue, combined with paper that may be acidic can make the paper brittle. Rolling it will only encourage brittle paper to break. If not too brittle, some humidity can be used to relax a rolled blueprint for flattening, without harming the image but do not immerse it or let moisture condense on the image.

· Interleaved with unbuffered, breathable tissue.

· Separated from other maps or photographs or folders made with an alkaline buffering. Exposure to an alkaline environment causes irreversible damage.

More information:

Ware, Mike. Cyanotype: the history, science and art of photographic printing in Prussian blue (London : Science Museum ; Bradford [England] : National Museum of Photography, Film & Television), 1999. Mr. Ware recommends Atlantis Silversafe Photostore, in a four-flap folder style for interleaving, p.131.

Ware, Mike. “A blueprint for conserving cyanotypes” (a paper presented at the 30th AIC Annual Meeting, Miami, FL, 2002), Topics in Photographic Preservation 10 (2003). Available as a Word document accessed at Mike Ware, Alternative Photography, in the section on "Conservation Matters."


All color photographs fade in just a few years if exposed to light and most will fade within 35 years even if stored in the dark. Black & white photographs are much more durable. One of the things that makes care of photographs complicated is that there have been numerous ways to produce photographs over the years. Cyanotypes are so sensitive to light that they will fade in just a few hours in bright light. Take the time to identify your older photographs.

Avoid areas with high temperature, high humidity and where the temperature and humidity fluctuate. Keep the area clean, and keep photographs away from direct sunlight. Fingerprints can permanently mar the image. Put each photo in a sleeve. Paper enclosures should be made of buffered or acid-free stock. Plastic sleeves may trap moisture and damage the image but may be okay in the proper environment. They should be made of uncoated polyester, polypropylene or polyethylene but watch out for additives to the plastic which may cause unintended harm. Do not use polyvinylchloride (PVC). Avoid “magnetic” photo albums, regular adhesive tapes, paper clips, rubber bands and rubber cement.

More information:

How should I store my family photographs and papers by NEDCC

Care of Photographs by NEDCC is one of several leaflets on “Photographs”. Check out the full list of leaflets on Photographs at Preservation leaflets.


The life expectancy of magnetic media is ten to thirty years, assuming the playback equipment is still available. (Do you still have a player for your old 8-track cassettes?) In general these items are made of some kind of carrier (plastic or paper) coated with a binder that contains metallic particles. The particles are magnetized to encode the images or sounds. Any of these elements can deteriorate, and usually it is the binder that goes first, becoming sticky.

Store magnetic tapes upright, and avoid areas with high temperature, high humidity and where the temperature and humidity fluctuate. Keep the area clean; dust is an enemy of these materials, and keep them away from direct sunlight. Wear cotton gloves when handling reel to reel tapes and don’t touch the playing surface of any recording. Keep them away from sources of magnetic fields such as stereo speakers and electric motors. Don’t rewind tapes until ready to play them. Clean playback equipment often.

Write down the who/what/when/where of tapes you made yourself. Consider making a written transcript of the conversation. In ten years those details may otherwise be forgotten. Plan to copy tapes you created onto new tapes every ten years or so. Archival storage would require the use of 16mm film or reel to reel tape but this can be expensive and you have to have the playback equipment. Digital copies are probably easier to make but come with the same cautions; digital file formats and storage media change frequently and can also deteriorate.

More information:

Care, Handling and Storage of Motion Picture Film” from the Library of Congress Preservation

Caring for your home videotape from The American Institute for Conservation. Look for the section on "Caring for your treasures" and choose "Home videotape."

Cylinder, Disc and Tape Care in a Nutshell” from the Library of Congress Preservation


CDs and DVDs are not indestructible as is commonly thought. As usual with preservation concerns, the proper environment, container and handling practices can have an impact on the life expectancy of a CD or DVD.

Remember also that a back up is needed, if this complies with copyright law. It will be necessary to migrate to another CD or DVD at some point and to watch out for software incompatibility as time goes by.

CDs and DVDs have a metal layer and a plastic layer that serves as the holder of the data layer. The metal layer reflects the light of a laser beam so the data can be read by the machine. If the metal layer gets damaged or scratched the data can’t be read. Oxygen or moisture can penetrate the layers and make the aluminum or silver corrode or become dull. If the metal layer loses it’s reflectivity, the data can’t be read.

Store discs upright (like books). Use a jewel case with a hub that keeps the surface of the CD or DVD from touching the case. Lacking an authoritative statement as to what the jewel case should be made of, consider that, for other library materials, these plastics are usually considered safe to use: polyester, polypropylene or polyethylene. Watch out for additives to the plastic which may cause unintended harm. Do not use polyvinylchloride (PVC).

Use a permanent water- or oil-based felt-tip marker, not a fine point or rolling ball marker. It should be made with pigments, not dyes to ensure that the writing is permanent. A water-based felt tip marker would be safe but it may not be permanent. These are sold by numerous vendors as "CD safe." It is best to do all marking in the inner circle at the center of the disc where there is no data. Do not use self-adhesive labels on optical discs.

More information:

Care of Archival Compact Discs National Park Service Conserv-o-gram Number 19/19 1996:Sept.

Electronic Storage Media from Conservation OnLine

Care and handling of CDs and DVDs - a guide for librarians and archivists by Fred R. Byers. Council on Library and Information Resources, 2003 with illustrations.

Predicting the life expectancy of modern tape and optical media” by Vivek Navale is accessed as part of RLG DigiNews. V.9:no.4 2005:Aug.15

Prepared by Connecticut State Library Preservation Office staff; last updated Nov. 2011.