This document provides an overview of preservation in archives and special collections. It defines key terms like preservation, conservation, and restoration. It discusses the historic, legal, and scholarly value of archival materials. It outlines important properties to consider for original archival documents like format, medium, substrate, condition, date, and artist/author. It also examines the stability of these properties. Finally, it details various agents of deterioration like heat, humidity, light, pests, inherent vice, and handling and provides strategies for monitoring collections and implementing controls.
Historical value implies age, association with a famous person or a significant event. Artifactual value can also be artistic value: visual, literary, or musical. Given that archive collections are often organized around associations with famous individuals, it is not surprising that some fairly ordinary items may take on heightened significance because they were owned or used by someone famous. Evidentiary value is the primary rationale for the very existence of most government and corporate archive collections. At the conservation lab where I worked in Philadelphia, there were two major legal cases involving document sent to the lab. In one instance, two technicians were hired to reassemble a collection of shredded documents involved in a lawsuit. In the second case, an auto manufacturer was being sued over a defect in a car made by a company it had absorbed in a merger. The mechanical blueprints were damaged and had to be repaired before presentation in court. As much as we might like to think that digital copies are a means of preservation, those two examples show that electronic copies would not be acceptable substitutes. Only the original documents or direct copies, such as blue prints can be considered authentic. Of course this gives us pause when we stop to think about the difficulty in archiving emails and instant messages, the fastest growing types of modern communications. Is your institution actually archiving old digital files? Or are you merely backing them up, so they can be deleted and subsequently erased when the new back-up overwrites the previous version? Legal obligations should be making us think about really archiving these things, so we are not required to search individual hard drives for previously-saved versions of files. Finally we get to textual value. This is the value most highly-regarded in many libraries, where copy-specific information is not known or considered valuable. It is easy to understand the artifactual value of unpublished manuscripts, hand-colored maps, and similar unique items. It is worth noting that published materials may also contain information within the paper, inks, and bindings that is unique to individual copies of a published volume. The more copies of a work exist and the more recently it was published, the more likely the individual copy has value only for the text printed on the page. In such cases, the words may be read more easily in electronic form. If the only value is in the text, then a sound preservation policy is one which emphasizes access to the text above all else. Unfortunately, this approach has caused losses to historical and artifactual value when misapplied. Policies for you collection should address the criteria for determining the extra-textual value before a decision is made to weed, discard, reformat, or rebind.
Many of the most vulnerable items in collections are those which do not fit neatly into a standardized format: oversized, undersized, and three-dimensional objects.
For a pop-up book, the act of folding and unfolding is an inherent part of using the book. Most items that are stored folded would be better served by flat, unfolded storage. Do you have letters that are stored folded? How about maps? You might want to think about whether these items have to sustain unnecessary handling in your collection.
This button had a sharp, exposed pin that posed a danger to readers and to associated papers.
Proper housing protects researchers from being stuck by the pin. It also prevents the pin from tearing the paper and from causing rust stains. The Mylar, cloth, and boards also protect the button from abrasions. The risk of theft is also reduced by such protective enclosures.
Your institution can save itself both time and money by ensuring that custom-made enclosures can be used for storage, study, and display. Most users can get the information they need without directly touching the original.
So how does this apply to collections of flat items? Polyester, polypropylene, and polyethylene sleeves are transparent, chemically-stable housing materials. Put them to work for you, and reduce wear and tear on your collections. As long as the items is not comprised of friable, powdery media, it can be protected by a box or a folder with a window.
In this example, the box opens for closer examination, and the foam support slides out of the hinge side of the box. Notches cut into the foam to permit removal, if and when it is needed. No housing is permanent. Think about how you will remove the item from its housing. A standard folder has only one closed edge, this makes it easy to remove items, but it also is not very secure. A traditional envelope has three closed sides, so staff and researchers are forced to bend the contents to remove and insert them. This may result in creases or even tears. An L-velope is sealed on two adjacent sides, providing both access and security. Other solutions are fold-lock sleeves and four-flap enclosures.
While you may not have any polyurethane foam artifacts in your collections, each of you work with collections that contain inherently unstable media. Contrary to popular mythology, most plastics are not indestructible. Plasticizers evaporate or sublimate, making the plastic shrink and become brittle. In the case of PVC or polyvinyl chloride, this also causes the release of hydrochloric acid. With cellulose acetate, acetic acid is released. The loss of plasticizer from this polyurethane foam has prevented the foam from bouncing back after being compressed in shipment. Libraries are fortunate that printing inks are generally rather stable. Unfortunately, archives and special collections are likely to contain less stable manuscript inks, copy inks, and photographic processes.
Hectograph copies or “dittoes” using synthetic dyes are much less stable than mimeograph copies printed in a slow-drying oily carbon black ink.
Look out for the enemies of collections, also known as the agents of deterioration. Your preservation plan should include monitoring of the storage environment. What strategies are you following to reduce the harmful effects of high temperature, humidity, and light levels.
An albumen print is a good illustration of this issue. When stored under the proper conditions, such photographs can be very durable. In the wrong conditions, we see yellowing in the highlights, a loss of density in the shadows, silver mirroring on the surface, overall cracking in the emulsion, and foxing stains in the paper.