The most common questions we receive from faculty, staff, and visitors relate to preservation of personal collections. Usually these collections consist of books, photographs, scrapbooks and diaries. To assist with these questions, we have assembled the following list of recommendations.
Ten Things You Can Do to Preserve Your Collections
This content was adapted from the tips posted at the Bates College Library.
Store material in an environment that is not too hot, not too cold, not too damp and not too dry. 60 to 70 degrees is ideal, and relative humidity or Rh should be between 40 and 50%. Large swings in temperature and particularly Rh is bad for material. If possible, get the materials out of the basement and attic and into a closet, preferably one that does not abut an outside wall.
Light causes permanent and irrevocable damage to materials. Store them in the dark. Prolonged exposure to sunlight is especially damaging to materials with color, such as color photographs, textiles, and watercolors. It is best to display a copy rather than an original. Make sure framed material is in UV filtered glass.
If you notice something that has mold, mildew or insects in it, isolate it immediately by sealing it in a zip-lock style bag. Mold and insects can cause serious damage to collections, so the key is to contain the problem as soon as possible. Then, you’ll need to resolve the issues that lead to the mold or insect outbreak (typically this means improving the environment and eliminating food sources, such as dust, crumbs, etc.); and then to clean (best done by a professional) or discard the affected materials.
Use enclosures sold by a reputable company such as Light Impressions, Conservation Resources, Gaylord, Metal Edge, or University Products. Products are often advertised as“archival,” however there is no standard for what is or isn’t archival, so don’t go by this term alone. Paper enclosures are often advertised as “acid-free,” which is a misnomer. This term typically means something that is Ph neutral, or has a Ph around 7 or 8. Some enclosures are buffered with calcium carbonate, which makes their Ph around 9. The calcium absorbs acid as papers deteriorate over time, keeps the enclosure Ph neutral longer and helps preserve the paper. Do not use buffered enclosures with photographs or hand-colored prints—the buffering has been shown to accelerate the deterioration of these types of materials. If using plastic sleeves, make sure they are polypropylene, polyethylene, or Mylar. Avoid polyvinyl chloride (PVC) sleeves. A safe bet is to use photographic enclosures that have passed the PAT (Photographic Activity Test). For paper enclosures, select one that is low lignin, as lignin accelerates deterioration.
There is no such thing as archival tape! Never tape, glue, or laminate anything that you want to preserve long-term. Adhesives used in tape, glue and the lamination process will cause more damage over time than they prevent. If something is torn, put it in a Mylar sleeve. Professional conservators use wheat starch paste and Japanese tissue to mend tears, a completely reversible process that is safe. A good rule of thumb to follow is that if a process is not reversible, then it should not be done.
Use pencil, not pen (once again, reversible). While the safest alternative with photographs is to put the information on a separate sheet of paper, this is not always feasible. If you have to label something like a photo printed on RC paper, be careful. This paper is coated with resin and using a pencil will etch the surface and indent the reverse side. If writing lightly with a pencil won’t do it, then use a pen with water-based, acid-neutral ink, such as those sold by Light Impressions. Label along the outside of the image on the back. To label a CD or DVD, write along the inner rim where the data layer is not located using the same type of pen. Make sure you include a question mark if you are estimating the date, author or subject of something—it is best not to mislead your successors.
Handle items carefully, preferably by edges or margins. For handling large items, such as maps, lift them using their diagonal (kitty-corner) edges. If working with photographs, CDs, DVDs, film and other material easily damaged by the oils contained in human skin, wear white cotton gloves. If you must clean a CD or DVD, use a clean, dry cotton cloth to wipe in a straight line radiating out from the center, never in a circle. Don’t wear gloves to handle most paper items, though. Paper documents are more prone to being damaged by someone wearing cotton gloves than not, because the gloves make it difficult to pick up paper. Just make sure your hands are well washed and avoid excessive over-handling. Don’t eat or drink while working with material. Not only can you cause immediate damage, you may attract rodents and insects, which can cause on-going problems.
Paper clips and staples rust over time, causing damage. Additionally, they can cause rips or tears. Rubber bands lose their elasticity over time and will dry up and stick to material. It is best to use a folded piece of acid-free paper to keep materials together. For bulky items, such as a scrapbook which is loosing its pages, you can tie it up using flat cotton “book tape” available from a library supplier, such as Gaylord.
Rather than displaying originals and exposing them to light for long periods of time, it is preferable to have a copy made. Prioritize making copies of items that are fragile or which are on inherently unstable material (cheap wood-pulp paper such as that used for newspapers, most color photographs, Thermofax paper, etc.). Photocopying newspaper clippings and faxes onto acid-neutral, buffered paper is a relatively inexpensive and easy way to preserve them long-term.
Software, hardware, file formats, and storage media change quickly and the computer industry is becoming less and less concerned about backwards compatibility. You cannot necessarily expect a new version of a software program to open an old file, especially a file more than a few years old. If you are digitizing something because you want it available long-term, you must undertake an ongoing commitment to migrate the file from format to format and from storage media to storage media.