Conservation Treatment of an 1842 Chinese Scroll Map

This is a guest post by Mary Elizabeth (Betsy) Haude. Betsy is a paper conservator at the Library of Congress where she performs conservation treatments on a variety of paper artifacts from the Library’s collections.

The vast collections of the Library of Congress are incredibly varied, and therefore treatment conservators must be prepared to apply their conservation skills to many different types of artifacts. That is how, in 2019, I was presented with a challenging project that involved eight tightly rolled 19th-century Chinese scroll maps. The task was to treat the maps so that they could be easily handled and consulted by Geography and Map (G&M) staff and researchers. Tamia Anaya and Grace Walters, two graduate students from Buffalo State College’s MA conservation program, were interning in the Conservation lab and I brought them onboard for the experience. Even though working on scrolls was somewhat new to the three of us, we were thrilled with the challenge.

The eight scroll maps are actually eight individual sections of one large woodblock-printed pictorial map, the 1842 Huang chao yi tong yu di quan tu, or Qing Empire’s complete map of all under heaven. East Asian scrolls are often comprised of a print or painting on paper that is adhered onto several layers of papers, and mounted onto a silk fabric. Wooden dowels are attached both ends to facilitate hanging for display. This is exactly what we found with each of the eight scroll map sections.

The staff of G&M brought the 1842 Qing Empire’s map to the attention of the Conservation Division’s Paper Conservation Section because all eight sections were in desperate need of treatment. Extreme creasing throughout the scroll sections made them almost impossible to handle by staff and scholars.

When the scrolls arrived at the Library, they required treatment. Each rolled section of the map had been lined with layers of thick and strong paper, and then tightly rolled and stored for a long period of time. The lining papers and the adhesive used to adhere them proved too strong for the thin Chinese paper on which the map was printed, and over time resulted in extreme rigidity of the scrolls in the rolled shape. Upon unrolling, the maps would distort and the paper would pitch upward into a triangular shape. This condition is described in paper conservation as “tenting” because it visibly resembles a tent. Not only did the tenting make the map sections hard to handle and reading the information on the inside difficult, it also put the original printing and paper at risk of abrasion and loss when the map sections were rolled and unrolled.

It is traditional in the conservation of East Asian scrolls in museums to remove the linings, and then re-line the print or painting. However, the main goal for the Library with this project was making the cartographic information accessible for scholars over time without causing further damage to the map. Therefore, we decided to try to alleviate the extreme tenting and creasing by humidifying and flattening the sections, and thus softening the rigid adhesive layers with the gradual introduction of water vapor. To determine if this type of treatment would work, I asked Tamia to humidify one crease locally using a system through which a dampened blotter was placed over a Gore-Tex membrane to deliver moisture vapor to the crease and gradually relax the tented area. Once adequately relaxed, the area was dried and further flattened by putting it between dry blotters and under weights. The test worked! The team was delighted to see how well the creased area responded. The next step was to figure out how to humidify and flatten the entire six-foot length of each section, rather than one crease at a time, in order to maximize efficiency.

As the map sections were in a traditional scroll format, they had dowels attached at both ends. This proved to be our biggest challenge in treating the sections overall, because we did not want to remove the dowels. Put simply, the three-dimensionality of the dowels would impede the flattening of the paper. We addressed this by cutting our humidification materials, thick machine -made Japanese kozo paper as a support for the maps during humidification, instead of the more standard polyester we materials, as it would expand with the scroll in the presence of moisture, and also had good wet-strength. This map sections and kozo papers were sandwiched between two sheets of Gore-Tex that was dampened on the outside. Finally, we covered the entire humidification package with a plastic sheet to prevent it from drying out, thus keeping the vapor moving in through the package and not out into the laboratory air.

Once the scrolls were sufficiently humidified, and all of the creases relaxed, it was time to flatten them. For the flattening part of the treatment, we placed the sections face-down onto thick wool felts allowing the dowels to rest outside the edges of the felts and not get squashed by the heavy-weight acrylic sheets used to flatten the humidified paper overall. We placed a larger felt on top of the sections to aid in drying and to ensure even pressure applied by the acrylic sheets.

After several days of drying the sections between the weighted felts, we were thrilled to see how flat they were!

So as not to encourage the creasing to return, we stored the sections onto archival tubes of a 3- inch diameter rather than rolling the sections tightly around the half-inch inner dowel as they were previously stored. We cut eight tubes, and covered them with Tyvek to provide a soft, smooth surface to store the printed map sections against, adhered a structure for one of the dowels to nestle in, and rolled up the individual sections.

A consequence of storing the maps on the tubes was that the diameter of the sections changed and new storage boxes were required. Preservation Specialist Jim Thurn and Conservation Technician Paul Asta made new boxes for the sections. Their box was designed to flip down on the short sides to allow for safer removal of the map sections and also included a padding of soft supportive material.  Finally, they labeled the boxes including cataloging information for ease of retrieval from the stacks by the G&M staff as well as handling guidelines.

The conservation treatment of the 1842 Qing Empire’s map was an invaluable experience. Even though Grace, Tamia, and I are not specialized in the conservation of East Asian scrolls, we creatively used the tools and techniques from our own training to efficiently stabilize the eight map sections. We also learned to work together to safely handle and treat these 6-foot long scrolls. The treatment was a success in that the scrolls can now be safely accessed by the Geography and Map staff and visiting scholars. In addition, their new housings will ensure their long-term preservation for future generations.

I owe a heart-felt thank you to two former Library of Congress employees who were instrumental in making this project happen. First, former Head of the Paper Conservation Section Holly Krueger began the project on G&M’s East Asian scroll maps and handed it off to me. And secondly, the late Ed Redmond, Vault Curator of the Geography and Map Division, freely shared his knowledge of the collection and offered his support along the way.

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