By TERRY BOONE
This is one of a series of occasional articles describing some of the efforts of conservators in the Library's Preservation Directorate in treating unique, fragile or rare items in the Library's collections.
The Conservation Division of the Preservation Directorate recently had the opportunity to study and repair a series of exquisitely beautiful but extremely fragile Chinese pith paintings. The nature of pith "paper," so different from real paper, made treatment of an important journal by William Speiden about Commodore Perry's first expedition to Japan a particularly challenging and rewarding one.
Ensconced between the pages of a 19th-century sailor's journal were 29 delicate pith paintings. The use of this spongy paper-like substance, which is soft, velvety and translucent, gave the paintings especially vibrant color and a unique dimensionality. However, the book format of the journal was compromising the richness of the images; the task for the conservators was to find a way to preserve both the content and the contextual elements of the two volumes while protecting the fragile Chinese pith paintings they contained.
Dated from March 1852 to February 1855, the "Journal of a Cruise in the U.S. Steam Frigate Mississippi," is a two-volume set, bound in half leather with marbled paper sides. Approximately 9-by-7-by-1-inch each, the small volumes were originally sold as blank books.
Throughout the volumes, Speiden combined his writings with captioned images of points of interest, social events, people and diagrams. Many of the images are hand-drawn or painted on the same page as the writing, but most of the inclusions were inserted between the written pages. Pencil and ink drawings, watercolors, rice paper and printed souvenirs were adhered to the blank pages with generous washes of glue.
The pith paintings, averaging 3 by 4 inches in size, were usually mounted in paper window mats held in place with paste and silk ribbon frames. The additional thickness of these matted paintings, as well as the other inserted art works and souvenirs, has caused the volumes to bulge, taking on a yawning scrapbook-like character. Over time, the added bulk has both damaged the inserted materials and caused the bindings of the journals to break apart.
The Nature of Pith "Paper"
Painted in watercolor and gouache, Chinese pith paintings were created exclusively for the export market. Typically small, these paintings depicted images of Chinese culture; those collected by Speiden show landscapes, harbor views, market scenes, and colorfully costumed natives, ranging from street beggars to likenesses of the imperial family. Because of its thinness, delicate, translucent appearance, and velvety surface, pith is often mistakenly referred to as rice paper. However, pith is actually unprocessed plant material cored from the stem and branches of a shrub native to regions of Taiwan and Southern China. Naturally limited in size, the pith is pared or carved into long, narrow sheets, flattened, and dried. Unlike manufactured paper made from macerated and matted fibers, the internal order of pith resembles the honeycomb structure of a wasp's nest. This complex cellular structure makes pith highly reactive to moisture. When paint is applied to the paper's surface, the cells swell, causing the painted image to take on a three-dimensional appearance with a jewel-like brilliance. While stunning to look at, pith paintings can be very vulnerable.
In order to conserve the journals, the conservator had to disbind the two volumes and repair the various components. The art works that were not mounted to the original pages were removed, cleaned and mended where necessary. Examination of the pith paintings revealed their susceptibility to damage. The soft spongy pith is easily pierced, compressed by rough handling, and fractured by the action of page turning. The structure and behavior of pith paper pose different treatment dynamics from those of traditional paper. While averaging less than .02 inches in thickness, the three-dimensional nature of pith causes breaks to occur along the cellular structure. When joined with adhesive, the sharp edges of the structure allow fractures to fit back together like a jigsaw puzzle. The paintings had to be permanently removed from the books if they were to be conserved.
The need to achieve a balance between respect for the integrity of the original volumes and the author's intent, and the changes defined by the physical limitations of the objects, led the conservators to an acceptable compromise. Working with the Information Technology Service (ITS) Scan Lab, conservators created high quality digital facsimiles of the pith paintings. The digital images of the pith paintings were then printed on thin Japanese paper and bound into the volumes, thus maintaining the visual integrity of the journals, while at the same time preserving the originals. The high quality of paper and printing inks which are available today made it possible to replace the originals with facsimiles. Materials testing conducted both in the Library's Conservation Division and elsewhere in the industry have identified printing papers, methods and materials that meet library standards for long-term stability.
To complete the conservation of the journal, the conservator rebound the two volumes and incorporated the pith painting facsimiles. The original order was maintained, the sewing structure reused, the boards reattached, and new leather selected to match and replace the missing spine leather. As a final step, the conservator matted the conserved pith paintings individually and boxed and housed them with the journal, thus ensuring the survival of these delicate but delightful illuminations.
Terry Boone is a senior book conservator in the Conservation Division.