In September, TSLAC Conservation worked on the Map Showing the Beaumont – Sour Lake – Saratoga Oil Fields of Texas (nd) from the Sam Houston Regional Library and Research Center in Liberty, TX. This 60 cm x 45.5 cm map features printer’s ink on machine-made, wove paper. Adhesive staining, tears, and losses presented challenges for its upcoming exhibit.
Map before treatment – Recto, spectral light
Map after treatment – Stain reduction and fills
A sticker-style label attached to the back of the map had caused pronounced staining on the front, upper right corner. Solvent testing revealed that a mixture of acetone, toluene, and xylene was most effective on the stain, likely indicating an acrylic-based adhesive. Successive poultices of the solvent mixture with Fuller’s earth provided some stain reduction, but better results were achieved by rolling with a solvent-dampened swab. Care was taken in applying the solvent mixture over a ball-point pen annotation that was revealed beneath the removed label. This ink proved surprisingly stable in the solvent mixture.
Adhesive staining and ball-point pen ink were revealed beneath the removed label.
The map was washed and deacidified on wet blotter to reduce overall staining and localized tidelines. Fills were constructed of handmade, Ruscombe Mill paper toned with water-thinned acrylic paint. Fills were cut to shape, pared along their edges for a smooth seam, and adhered with wheat starch paste. Extensive edge tears were then mended with NARA heat-set tissue.
Toned, shaped fills await final trimming.
In the lab in May is Pressler’s Map of Texas from 1867. Charles Pressler was a noted draftsman and cartographer who immigrated to Texas from Prussia. He created well-known Texas maps while working with land empresario Jacob de Cordova and with the Texas General Land Office.
Pressler’s Map of Texas is a pocket map, which is the 19th century version of the Rand McNally road map one might have carried in a car’s glove box prior to GPS systems. Pocket maps are generally large, hand-colored documents that fold down into a small, textile-covered case that is stamped with gold foil and other decorative elements.
Pressler’s Map of Texas, an 1867 pocket map.
Because repeated folding can damage fragile paper, conservators often remove pocket maps from their cases and flatten them for future storage and use. While this treatment is usually the most responsible course of action, it detracts somewhat from the item’s artifactual value. After treatment, the map is quite physically different.
In this case, we encountered a unique circumstance: there are actually two copies of this item in our collection. It so happens that the other copy has already been removed from its case and flattened. Since the flattened copy will be the primary access copy, this created an unusual opportunity to preserve a pocket map in its original format.
First, creases and wrinkles received local humidification and flattening to help the item fold more efficiently. Then, existing tears at fold lines were mended with wide strips of Japanese tissue and wheat starch paste.
Mending tears at fold lines.
The map was carefully folded back into its case and the front board (detached) was reattached with toned moriki tissue. Because there is another access copy, this pocket map has been returned to its original format.
- Repaired case with map folded inside.