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There is a demonstrably wide variety in material and applicability of gels, emulsions, and cleaning systems that can be incredibly overwhelming and slightly daunting. As an emerging conservator, I’ve had the luck to be in enough places at the right times to learn snippets of many of the concurrent theories and systems. The Modular Cleaning Program, the A-F aqueous recipes delivered in emulsions and gels, and proprietary Nanorestore© products have all entered my brain, been cocktail-stirred, and poured out as a largely murky understanding of how these big three methods relate (or don’t) and what they best target. I have a long way to go and need constant refreshers every time I approach a new substrate and surface.
This presentation was useful as a concise overview of case studies that successfully employed the use of various gels and emulsions to clean both very small things and very large things at the University of Pennsylvania Museum of Archaeology and Anthropology. I was surprised to see the use of a Pemulen gel on objects because it is difficult to rinse and not used on porous surfaces, so I’d be interested to know more about any barrier layer they used between surface and gel or if they have a specific rinsing protocol of which I am unaware. Each case study profiled a different material and surface accretion to be removed, highlighting the versatility of gels and their effectiveness on a case-by-case basis, requiring thoughtful testing of all materials and options. They used rigid gels and liquid gels and no gels – based on the material to be removed and the stability of the substrate.
It was useful to be reminded that not all surfaces need to be cleaned!
The presentation also highlighted the lab’s use of silicone solvents. They have found them (specifically D4) useful to restrict aqueous cleaning to the surfaces of objects, preventing tide lines and dirt penetration. This class of materials is highly controversial, which was made clear during the Q&A portion of the talk.
Silicone solvents, such as the cyclomethicone D4, have an unknown/understudied/unpublished effect on the human body. Unfortunately for those disseminating information about their carcinogenic effects, there is no readily available alternative to their use and they are so *incredibly* good at their job – to restrict cleaning to the relevant surface. Some cleanings could not take place correctly without this pore-filling barrier material. However, as was made clear in the Q&A section, ongoing research that has yet to be published is finding that, in addition to the known negative effects on the environment through buildup in groundwater, these silicone solvents may not be processable by the human body. Research on this topic is ongoing worldwide and it is a complex problem to demonstrate the effects on human bodies.
There was much to be considered. While conservators routinely work with toxic chemicals and ionizing or radioactive equipment in small doses as necessary, it is so incredibly important to discuss mitigating factors and the real risk of using chemicals in uncontrolled ways. All of us, of course, want to be safe.
Despite the D4 tangent during Q&A, it is clear that different kinds of gels are being used to thoughtfully address the cleaning of objects by conservators at the Penn Museum. They have addressed modern protective coatings, sooty soiling, and wax with attention paid to the desired display aesthetic and the irreversibility of the cleaning process itself.
#AICmtg19 #Gels #Featured #47thAnnualMeeting(NewEngland)