The Treatment of Two Oversized Antique Maps

By David Chandler, Chief Conservator of Works of Art on Paper

While modern maps help to tell us where we are going, antique or vintage maps can be helpful in showing us where we have been.

The two maps we will discuss in this article were created in the late 19th century. The linear images were the result of a very exacting printing technique called engraving, which permitted the engraver to work only with single lines and closely placed hatch marks to create shadows. This is especially apparent where water is depicted near land. The engraving technique is nicely illustrated in the Map of North America, engraved by H.S. Tanner, Philadelphia, in 1822.

(Above) Pre-treatment: The Map of North America. Notice the water staining and tide line visible along the bottom edge.

The Map of North America appeared quite dark in tone due both to the poor paper quality, which contained wood pulp, and the varnish layer that was added at some point in time to protect the surface. Testing the surface helped establish a method to remove the varnish layer in a uniform way; this was done section by section. Removal of the varnish made it possible to bathe this large map in the conservation washing table. The bathing process both chased the yellow-brown paper discoloration and enabled the conservators to begin the delicate process of removing the old backing and carefully swabbing the old adhesive layer from the back of the map. Fine cleansing attention was given to the large tide line, or water stain, along the bottom of the map while the work was still wet.

(Above) Detail: Varnish removal

(Above) Detail: Water bath

When cleansing and careful rinsing was concluded, the preparation for backing was carried out. A large, sturdy sheet of Asian lining paper was selected and prepared with fine starch paste to add a new backing to the map. Lining or backing adds supporting strength to the weakened and fractured maps. The before treatment photos illustrate the two old folds and numerous resulting losses from both age and poor handling.

(Above) After water bath and lining to Asian lining paper for stability.

Following the backing and drying process, paper fills were prepared and attached to fill the areas of loss. These fills were carefully constructed and toned to blend in with the new color of the sheet following cleansing.

(Above) Pre-treatment: The Map of Berkeley County, West Virginia

The Map of Berkeley County, West Virginia, while printed on a similar paper as the Map of North America, is much more darkened and degraded. The map was so embrittled and fractured with numerous small broken fragments that it was necessary to face the surface. A facing is a light-weight, temporary lining which is pasted down to the surface with a low-adhesion paste. This made the map a bit stronger and enabled the conservator to carefully mechanically strip the old fabric backing (see photo). Once debacked, the map was carefully cleansed in a shallow water bath and old adhesive remains were swabbed away from the back. The water staining and dark sheet tone were reduced, and the work was prepared for lining. The new backing (lining) is very similar in material and attachment to the Map of North America.

(Above) Detail: Mechanically removing the old fabric backing.

(Above) Detail: After removal of fabric backing

The final treatment result of this West Virginia map was just as expert and visually satisfying as the Map of North America.

(Above) Post treatment: The Map of Berkeley County, West Virginia

The end result of these treatments are two large, important maps with greatly reduced paper darkening and overall support to keep them stable. These treatments were carried out by Olga Knopf, Senior Conservator of Works on Paper, and Brian Kapernekas, Associate Conservator of Works on Paper. Their experience with oversize, problematic paper artifacts of this variety is expert. All of the conservation efforts described here make the Map of North America and Map of Berkeley County, West Virginia a pleasure to study and enjoy.