Partway through the initial flattening treatment. William Bennett, Smithsonian Institution Archives, SIA_CONS_20190627_0005, 27 Jun 2019.

Navigating Treatment of the Dawson Map

Our treasures can pose significant—and often unexpected—challenges, like when a map has been attached to a hotel linen. See how our staff tackled a complex intervention in progress!

As our readers know, the Archives’ collections are immensely varied. Even within groupings of collection items, such as our oversize flat documents or our field books, the content, structure, medium, and format can differ tremendously. We often come across surprises, and many of these have been highlighted in our posts (check out some of them, linked below). This is one of those gems. 

A printed map, marked with red and brown inks, is unfolded showing the entirety of its information.

When our archivists brought this particular item to my attention, I had no idea that it would prove to be so fascinating. A rolled-up map normally wouldn’t elicit too much excitement, even in poor condition; some humidification and flattening would be necessary prior to mending tears and filling losses, but surely not more than that.

In fact, it proved not only more complex, but infinitely more interesting than I could have imagined.

This map, published by the Automobile Club of Southern California (one of the founding motorists’ groups of AAA) in the 1920s, was utilized as a tracking document for botanist E. Yale Dawson, a field scientist who was collecting cactus specimens on an expedition in Baja California. After annotating the map to show the route he traveled and the points where he collected each cactus, he attached the unfolded paper map to a piece of hotel linen, likely a bedsheet, which features an embroidered name—“The Admiral.” An additional piece of fabric was attached, a coated teal textile that likely served as a water-resistant outer wrapping, complete with ties to secure the entire assemblage.

As you might imagine, sewing two different materials together poses long-term challenges. Paper and cloth both expand and contract naturally as humidity levels in their environment fluctuate (we describe materials like these as “hygroscopic”), however, they don’t do so in precisely the same way. Because the map and lining were attached, this put tension on the cloth and paper, leaving the weaker material—the paper, in this case—to give when the strain became excessive, leading the map to tear along the sewing.

While the sewing may have seemed like a good idea to Dawson, what it essentially did was create long lines of perforations, which caused the tears we now see in the map. The machine he (or a friend) used to attach the map and cloth lining also appears to have been problematic; as part of our assessment, we consulted with textile conservator Maria Fusco from the Textile Museum at the George Washington University, who observed that the bunched bobbin thread, visible on the rear of the map, indicated that the sewing machine had been under improper tension when used. The lining itself raised questions, leading to hypotheses that Dawson pilfered the sheet from a hotel he stayed at. Not a shining moment, perhaps.

A small portion of a printed map is shown atop a piece of white blotter. Folds and tears interrupt t

With Maria’s advice at hand, we determined to separate the different components of the map, preserve them in a custom enclosure that would demonstrate the relationship of the pieces and their original assemblage, and make mends to the paper map to improve its legibility and thus its utility as a research document.

I first removed the sewing by carefully cutting the thread at intervals and using tweezers to gently pull the thread free. With both textile components loose, I observed a sizable burn mark on the reverse of the bedsheet, which indicates that perhaps a housekeeper had accidentally ruined the bedsheet and Dawson seized the opportunity to give it new life as a lining, rather than sending it to a landfill.

Initial flattening treatment utilizing 3% gellan gum gel atop Gore-Tex fabric. William Bennett, Smithsonian Institution Archives, SIA_CONS_20180619_0010, 19 Jun 018.

Partway through the initial flattening treatment. William Bennett, Smithsonian Institution Archives, SIA_CONS_20190627_0005, 27 Jun 2019.

Next, I began to explore methods of humidifying the map in order to flatten it. Local techniques were used first, including blocks of gellan gum gels, applied through Gore-Tex along creases and then over larger sections, to gently introduce moisture to relax the paper, and then allowing the humidified sections to dry between blotters and under weight. This reduced distortions to a degree, but we determined to attempt a slightly more aggressive technique—the use of our humidity chamber and associated suction table. This allowed us to gently humidify the entire map and draw the moisture out quickly, preventing the media from bleeding and also allowing the map to dry with its torn edges aligned, held down by the draw of the suction table vacuums. Small sections were worked on, one at a time, using rubber sheeting to mask off the other areas.

Setting up the second flattening treatment in the humidity chamber. Emily Niekrasz, Smithsonian Institution Archives, SIA_CONS_20190110_02, 10 Jan 2019.

Adjusting the map prior to placing the rubber sheeting and beginning the humidifcation process. Emily Niekrasz, Smithsonian Institution Archives, SIA_CONS_20190110_10, 10 Jan 2019.

Our next step will be the final piece of the treatment: formulating a lining to strengthen and support the map, rather than individually mending the numerous tears and breaks. We plan to use a heat-set mending tissue—one coated with a heat-activated adhesive that will avoid introducing moisture and thus protect the inks. Stay tuned for an update!

A printed map is viewed at a low angle, showing fewer planar distortions and presenting a flatter ap

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