Preservation 101

By Angelique Schuler, Graduate Student Processor

One of the many arguments against the MPLP method for processing is that not enough attention is given to preservation issues. However, in my experience using MPLP at the BMRC we have always looked out for conditional issues that may cause harm to a collection. We do care -- we do want the materials processed and out of backlog – but we will also address pressing conservation and preservation issues that affect our collections. Our hope is that we can address issues quickly and effectively.

At the BRMC we are expected to process each collection in a timely manor. However, we are on the constant look out for damage to documents, fragile photographs, evidence of or live pests, nitrate film, dirt, mold, audio-visual materials, and artifacts. Should any of these issues be spotted a form is filled out immediately to address the issue. In my time as a processor, I have personally encountered acidic/fragile paper and books, mold, dead and live pests. The simple reality is that these and other preservation concerns happen in nearly every repository.

Depending of the repository funds for preservation we assess the need and address them to our best ability. Some of the various ways that preservation concerns are address are by digitization, isolation, encapsulation, and changes to the micro and macro environment that houses the materials. An additional unique way that preservation issues are addressed is through freeze-dry technology.

Digitization of damaged documents should be the first step. Digital copies are not the same as the original but sometimes the educational value is in the content and not presentation of our materials. The price of scanners has steadily gone down through the years. So for around 100 dollars you can purchase a good scanner to preserve damaged documents. Digitization should be done for all documents affected before other preservation takes place because the more time that elapses the more the documents will change.

Isolation is taking the damaged item and placing it away from other items. The lowest cost way to do this in a repository is to have an archival box and folders set aside for contaminated items. Each item should receive its own folder and the archival box. Should mold be the issue the archival box should then be wrapped in a plastic bag to prevent the spread of spores.

Encapsulation uses mylar film and archival tape to enclose the damaged document. To properly encapsulate an item the mylar must be at least two inches larger than the documents parameter. The archival tape should wrap around the document without touching the document and must not attach at the corners. The room at the corners allows the documents to breath and also allows the archivist to easily reopen the encasement should need be. When done properly Mylar encapsulated items appear to be laminated but this form of preservation does not change the integrity of the document at all. Again the items should still be isolated from non-affected materials in an archival box.

The best treatment damaged archival materials is to send them to a freeze-dry facility. However, freeze-drying technology is expensive. Typically repositories are charged per cubic foot to treat their documents. Depending on how much or little you have to treat this form of treatment may not be a feasible option. Several freeze-dry facility function in the United States.

For my Chicago readers, we have a facility located in Skokie, Illinois called Midwest Freeze Dry. I was fortunate enough to tour Midwest Freeze-Dry when dropping off a collection that had a silverfish infestation. I am impressed by how the facility functions. The staff at this facility is enthusiastic about preservation, which is awesome to see! I would highly recommend the use of Midwest Freeze Dry should you have preservation emergency.

The science behind freeze-dry technology is to place archival documents such as: paper, books, photograph, and even textiles, in an airtight vacuum chamber. The items in the chamber are brought to below freezing temperatures. The control of the vacuum allows the preservationist to lower the pressure in the vacuum, which allows the materials to be taken from a frozen to dry state without passing through the liquid phase. The water vapor is removed from the chamber leaving the archival materials fully dried.

Chemicals can be added to the freeze-dry process to enhance the longevity of archival documents. For example, paper produced between 1880-1990 was made with a PH of about 7. So over time the paper quickly becomes acidic and brittle. During the freeze-dry process a vaporized alkaline buffer can be sent through the paper which will move the PH up to about 11. This will not correct the damage done but will immensely help to slow down the aging process. Pests can also be treated via freeze-drying. The freezing phase of the process will kill virtually all live bugs and eggs. I expect that freeze-dry technology will continue to grow and help our field!

My hope with this blog post is to enlighten you about the preservation work that we do at the BMRC. I also hope that this has been informative to other repositories or individuals that have document preservation concerns. Always remember to never do something that changes the integrity of a document. When in doubt about what to do -- folder and box the items and keep them in isolation!

Cheers to processing and preserving!