By MARK ROOSA
In 1987 the Library began a project to conserve 40,000 important drawings that document the history and development of architecture, design and engineering in the nation's capital.
The project, Washingtoniana II, was made possible through support from the Morris and Gwendolyn Cafritz Foundation. It aims to stabilize these drawings from collections of the Prints and Photographs Division.
The drawings, which date from the late 18th century to the 1980s, were acquired by the Library through copyright deposit, purchase and gift. The collection includes items from some of the most important architectural competitions held in the United States, including the United States Capitol Competition of the early 1790s, the competition to design the first building of the Library of Congress and the competition to design the Vietnam Veterans Memorial. As many of the drawings arrived at the Library tightly rolled or folded and in various states of disrepair, one of the chief goals of the project has been to flatten, stabilize and provide safe housing for the items so they can be accessed by researchers.
Many of the drawings are on good quality handmade laid or wove papers; however, a large number are on poor quality wood pulp, lignin-containing papers that become brittle over time. To complicate matters, the drawings are composed using a wide variety of inks, pencils, watercolors and other media. In addition, the size of objects and their formats vary considerably, from sketchbooks and simple renderings to final master presentation drawings that were submitted to clients or in competitions.
By 1998 essentially all of the drawings had received basic preservation housing. However, a number of late 18th to early 19th century master presentation drawings had a special problem that required further attention. It seems that these small to oversize drawings -- some of which pertain to the early design and construction of the U.S. Capitol -- had been backed with up to three layers of bond paper, acidic kraft paper and linen fabric using an adhesive that was now causing damage. The culprit was a water-soluble paste used in the Government Printing Office between 1930 and 1960 for a variety of treatment applications. (The GPO established a branch bindery with the Library in 1900.) The paste was now beginning to turn brown and migrate through the backing layers into the irreplaceable drawings.
To address this problem, the affected drawings were earmarked for a second phase of more intensive conservation treatment. During this past year, staff in the Conservation Division have begun to remove the backing material and the damaging adhesive from 16 of the several hundred affected drawings. This involves first dry cleaning the front of each drawing with erasers so that subsequent use of moisture does not "set" the dirt. While dry cleaning, care must be taken to avoid removing any drawing media. Next, the painstaking process of removing the backing layers begins. With the drawing face down, the linen backing is peeled away to reveal the underlying paper backing. This second layer of paper is mechanically removed with the aid of scalpels, spatulas and peeling, finally exposing the last layer of backing paper.
Removing this last layer requires the application of limited moisture to the backing paper using damp blotters, steaming, or felted Gore-Tex, sometimes with the addition of enzymes to dissolve the adhesive. In cases in which the drawings are stained and yellowed, and their media is not soluble in water, washing in purified water is carried out. Once the final backing material is completely removed, any tears are mended with Japanese paper and a reversible wheat starch paste. Then the drawings are carefully flattened before being placed into a mat or other protective enclosure.
While it may take years to treat all of the Capitol drawings and correct the damage caused by the paste, so far a good start has been made by curators in the Prints and Photographs Division and conservators in the Conservation Division toward securing these important chapters of the nation's architectural history. With the continued application of conservation expertise to bear on the problem, the Library is confident that these magnificent drawings will be preserved for future generations of users.
Mr. Roosa is chief of the Conservation Division. This article was prepared with the assistance of conservator Linda Stiber Morenus.