In keeping with the conference theme of Practical Philosophy, or Making Conservation Work, Ariel O’Connor, currently at the National Air and Space Museum and formerly at the Walters Art Museum in Baltimore, presented a talk where an imperfect treatment method proved to be the best option. A nineteenth century Persian water pipe, or nargile, made of gilded silver and elaborately decorated with gemstones, was heavily tarnished and needed to be cleaned in preparation for an upcoming exhibit. The water pipe was first analyzed with XRF to determine the treatment; XRF indicated silver with copper, gold, and lead, but no mercury, suggesting the object was gilded with some process other than mercury gilding.
Test cleanings were done with several standard methods for reducing tarnish mechanically: cosmetic sponges, Duraglit polish, precipitated calcium carbonate, Long Shine silver polishing cloth, and Mars Erasers. Acidified thiourea, a chemical method of reducing tarnish, was not initially considered because of research showing the problems of thiourea – leaching of copper, microetching, and long-term detrimental effect of thiourea residues. (See for example, a recent article by Contreras-Vargas et al, “Effects of the cleaning of silver with acified thiourea solutions” in Conference Proceedings of Metal 2013.) While the mechanical methods, especially the erasers and sponges, were easy to use, the final appearance of the polished surface in the test cleaning areas was not as golden as expected.
Analysis with XRF led to a frightening conclusion: even the gentlest mechanical methods, such as a cosmetic sponge, removed gold from the surface. And as the object was gilded with a method other than mercury gilding, the gold layer was already very thing. Analysis after a test cleaning with thiourea, however, did not show the same loss of gold. The decision to clean the object with thiourea was reluctantly made. Steps were taken to use thiourea as safely as possible: dwell time was minimized, the surface was immediately rinsed with deionized water, and the work was performed in the fume hood because of the generation of poisonous gases. O’Connor introduced a novel technique for applying and rinsing the thiourea. Strips of non-woven cotton Webril Handi-pads were placed on the object then wetted with thiourea applied by dropper; rinsing was also performed with the handi-pads. Cotton swabs were used as little as possible because of the possibility of abrasion of the surface.
The treatment raised the important question of when is it acceptable to use a method that has been shown to be damaging. O’Connor articulated why, on this occasion, chemical cleaning with thiourea was the lesser of two evils. I look forward to seeing more research on the topic of cleaning gilded silver as well as discussion of the ethics involved in this treatment.
Tag: OSG
43rd Annual Meeting – Objects Specialty Group Tips Session, May 16, “Lacquer Fills” by Ellen Promise, with Jessica Chloros and Holly Salmon
During the OSG tips luncheon, Ellen Promise, currently of Historic New England and formerly of the Isabella Stewart Gardner Museum, presented new techniques for filling and inpainting lacquer. The techniques, developed in collaboration with Jessica Choloros and Holly Salmon, are readily applicable to many types of objects, not just lacquer.
Lacquer objects, especially those damaged by light, have very sensitive surfaces; therefore creating fills in situ can be dangerous. In the technique presented, Golden Acrylic Regular Gel Medium in matte was mixed with acrylic paint to a frosting-like consistency. The tinted mixture was then cast out onto silicone release mylar. After drying, the paint film remains flexible, has the bulk required for a fill, and resembles the sheen of aged lacquer. The paint film is trimmed to shape with a scalpel and then adhered in place with fish glue or B-72. While the fill isn’t invisible at the edges, it is harmonious with aged, cracked lacquer and remains reversible.
Promise also described her experiments with inpainting lacquer, specifically the fine gold lines often found on these objects. While acrylic paint is easy to use, the texture and shine is often not a good match. Promise tested several other options – metallic pens and markers, metallic paints, and mica powders dusted over sizes. She evaluated the materials for color, texture, gloss, and adhesion to an acrylic substrate. For the object in her case study, a Chinese export table in the collection of Historic New England, she had the best results with a Decocolor opaque paint marker. The marker was a good color match and had a high pigment load without bulk. The marker, which produced a fine line, could be used directly on the fill, or the ink could be dispensed into a palette, mixed with solvent, and brush applied.
42nd Annual Meeting – Joint Architecture and Objects Session, May 29, "The Cultural Production of Tourism at Lake Tahoe: Exploring How Cultural Heritage Preservation Is Impacted By Tourism," by Catherine Magee
This paper was a departure for a specialty group presentation in that it focused not on the conservation or technical study of material culture, but on the creation and consumption of cultural narratives and landscapes. Magee noted that conservation work informs and perpetuates stories about people, places, and things, and made the point that conservators are generally comfortable thinking about our work in the context of education, science, and academic scholarship. But she proposed the idea that we must also consider our role in the broader context of tourism, since the primary products of our work – conserved objects and sites – are most often intended for consumption by the general public, also known as tourists.
Her paper included a brief overview of tourism studies, examining the impact of tourism on different kinds of sustainability: economic, ecological, and cultural. The bulk of the paper was spent illustrating the latter point, looking at the ways tourism influences our perception of history and heritage by creating hybrid tourist/cultural heritage landscapes and influencing cultural memory.
Magee used two examples from her doctoral research, which focuses on the landscapes and material culture of the Washoe people in the Lake Tahoe area. The first example was Cave Rock, a pilgrimage site of major spiritual significance for the Washoe. The site was progressively destroyed by tourism, evolving from a culturally significant tourism site, to a pathway for a road, to a mecca for rock climbers. The second example focused on an iconic Washoe basket form, the degikup, and its most famous creator, Dat-So-La-lee. Magee examined the shared mythos of Dat-So-La-Lee and the degikup in detail, revealing the stories, and the basket form itself, to be products created for tourism.
The role of the conservator in shaping the destiny of a site like Cave Rock or the narrative surrounding iconic artifacts and artists like the degikup and Dat-So-La-Lee was not explicitly discussed. It’s not difficult, however, to imagine the complexity inherent in conservation decision-making for the kinds of tourist-hybridized sites, objects, and narratives explored in this paper. Magee argued that we conservators will discharge our responsibilities best if we develop a better awareness of our role in the cultural production of tourism. With that awareness, we can improve our agency in the process and generate better outcomes for sites, objects, and the communities we serve.