"Sizing" up Paper Conservation at the American Academy of Bookbinding

Wednesday, January 29, 2014

In November I traveled to the American Academy of Bookbinding for a class on Basics in Paper Conservation, one of the required classes for students in the Book Conservation Diploma Program. Renate Mesmer, Head of Conservation at the Folger Shakespeare Library, presented morning lectures covering the history of paper making, basic paper chemistry, damage analysis, writing condition reports, and material studies. Various repair techniques for tear and losses were discussed, as well as humidification, basic washing, and dehumidification of paper. In the afternoon, we applied knowledge gained from those lectures to hands-on conservation treatments.

Washing, de-acidifying and sizing were the topics of most interest to me, as those are treatments we don’t often perform in the lab. Washing is considered to be an invasive treatment because of potentially irreversible changes occurring in the paper. The visual, tactile and dimensional characteristics of paper may all change, to varying degrees, during the washing process. Washing can also remove sizing, fillers, and printing marks, such as plate imprints. Wet paper is also very vulnerable to physical damage, and therefore must be careful while handling it. That said, washing can be very beneficial in improving the visual appearance and stability of paper as discoloration and damaging acids are removed in the bath.

De-acidifying and sizing are relatively straightforward treatments, with only a few considerations compared to washing. A de-acidifying bath introduces an alkaline reserve, or buffering agent, into the paper to raise the pH and protect the paper from those pesky acids. In class we used magnesium carbonate as the buffering agent. It was made soluble by adding carbon dioxide via a Soda Stream (a handy device for making your own carbonated beverages). The paper is bathed in the magnesium bicarbonate for 15-20 minutes. Once removed, both the water and carbon dioxide evaporate leaving a magnesium carbonate reserve in the paper.

Sizing adds strength and improves the feel of paper. It also provides resistance to abrasion and adds dimensional stability. Since not all papers are sized, this step may be optional. To size or not to size? These factors are taken into consideration: the future use of the paper, visual character of the paper before and after washing, and physical characteristics of the paper. I chose to size one of my prints because the paper fibers were noticeably softer after washing. Besides, I was there to learn! Gelatin was my sizing agent of choice since it was most likely used when the print was made in the 1860s.

My treatments went well, washing was de-mystified and I left feeling more confident in my ability to successfully perform washing treatments when circumstances warrant. Being back in Telluride wasn’t so bad, either.

Sharon Fickeissen is the Conservation Technician at Hagley Library.