By HEATHER WANSER
Asian maps are often created as scrolls, but this format has inherent problems. The papers and adhesives used in the scroll are flexible and pliable when freshly made, but eventually they become brittle and inflexible. Over time, the rolled paper takes on the shape of the dowel, thus adding stress to the paper every time it is unrolled. Another problem is that the design is rolled against itself, which causes abrasion every time it is unrolled and re-rolled.
The customary approach for treating a fragile scroll is to take it to a scroll mounter, who painstakingly removes all paper linings and replaces them with new ones. The back of the new linings are then waxed and burnished to create a smooth surface to prevent abrasion of the design.
The challenge for the conservator is to treat an Asian artifact in a manner that respects its cultural heritage while offering a practical solution that meets the needs of the conservation and custodial staff. Interestingly, western paper conservators use many of the same methods as Asian conservators and scroll mounters. Japanese tissues, specialty brushes, wheat starch paste and, above all, many of the same mending techniques, are routinely used in the Library's Conservation Division.
While many Asian maps are created as scrolls, there are other traditional formats: wall maps that are folded to smaller sizes; long folded maps (referred to as accordion style); or atlases, which are bound in a manner that is uniquely Asian. There are even a few maps that are formatted as fans. Each format requires a different housing and careful handling to ensure that its condition is preserved.
An early 19th-century Chinese map that was recently given to the Library's Geography and Map Division is being treated in the Conservation Division because of its fragile condition upon receipt. It is described as a map of the world; however, it is schematic in design rather than being cartographically correct, depicting European countries as islands. It belonged to the donor's grandfather, a Baptist missionary, who lived in China during the 1840s. He used this map to illustrate the "outside" world to his Chinese students.
The map is a wood block print on thin Chinese paper with multiple linings for support. The woodcutter cut out the artist's lines on the block, instead of the spaces between them, leaving the unprinted area to create the linear design. The areas of land are printed in dark blue with the oceans printed in a lighter blue.
The map consists of eight vertical sections that are mounted as scrolls in accordance with age-old Chinese traditions, with dowels attached at each end. The top dowel has a string loop for hanging. When the eight sections are assembled, the map is approximately 92 inches wide and 51 inches high.
The map, originally created as a series of scrolls, arrived at the Library in very poor condition. The paper was so brittle that the scrolls could not be unrolled without causing the paper to tear or break. The top dowel on each scroll was already detached, and each scroll had numerous tears, breaks and paper losses. In addition, the blue printed media was friable (a conservator's term for chalky).
The traditional conservation treatment, removing and replacing the old linings, is not an option at this time, due to time constraints. So the goal of the treatment is to physically stabilize the map to prevent further damage so that it can be made available to researchers.
The first step of the treatment was to relax the paper with humidification so that each scroll could be safely unrolled. Japanese tissue mends, adhered with wheat starch paste, were applied to the back of the scroll to hold the tears together. The media was consolidated by lightly misting it with a solution of warm water, ethanol and sturgeon glue derived from dried swim bladders. This special glue is known for its strong adhesive properties in very low concentrations. Preliminary testing established the effectiveness of the solution without causing any visual changes to the color.
The dark blue media was thought to be indigo, a color commonly used in Chinese artifacts. However, color infrared photographs taken by Minah Song, an advanced paper conservation intern, revealed that the blue pigment was actually Prussian blue, which appears very differently from indigo on the infrared film. The use of Prussian blue is somewhat unexpected as it was, at the time, a more expensive pigment. This information helps scholars understand Chinese printing practices during the early 18th century.
Each scroll will be stored flat in a polyester film encapsulation, one that is modified to accommodate the bottom dowel. The remedial treatment has stabilized the map, allowing it to be served to researchers; a more extensive treatment can be considered in the future.
Heather Wanser is a senior paper conservator in the Library's Conservation Division.