ConNext-2021

42 The Use of Agar Gels for the Cleaning of Wooden Water ‐ Gilded Surfaces KEYWORDS: cleaning, agar, gels, gilding, water-sensitive surfaces. Agar is a rigid polysaccharide gel that has been introduced in conservation cleaning treatments through the intermediary of Richard Wolbers in the early 2000s. Since then, several studies have shown the great potential of this natural product for the cleaning of water-sensitive surfaces. The purpose of this master’s thesis research was to assess the efficiency of agar gels for the cleaning of wooden water-gilded surfaces. These surfaces are complex to clean, as they are extremely sensitive to water, while water is often an indispensable tool for the removal of dirt layers. As such, they are often damaged during cleaning campaigns. Therefore, there is an urgent need to develop more controlled methods of cleaning for their preservation. This research included an experimental study that aimed to identify the appropriate conditions for an agar gel to be effective as a cleaning agent for wooden water-gilded surfaces. Tests were first carried out on mock-ups reproducing historical recipes and covered with artificial dirt. Agars from Kremer®, CTS®, and Sigma & Aldrich®, were prepared in several concentrations (4%, 6%, 8%), and applied with different methods (rigid, fluid, and destructured). The results were assessed through observation before and after treatment, with the naked eye (in ultraviolet light and visible light) with a stereoscopic microscope, and through analyses of brightness. Criteria of assessment were the efficiency of removing dirt, the absence of alteration (colouration, stains, microcracks, etc.), and the ease of application. Then, according to the results of the previous phase, an agar gel was used for the cleaning of a gilded frame covered with real dirt. This research has shown the potential of agar for providing a controlled cleaning of wooden water-gilded surfaces. Indeed, the agar allows to limit the penetration of water into the substrate and to reduce the need for mechanical action on the surface. However, agar must be used with great caution as it can be risky on gilding in poor condition, especially when the agar is applied fluid, as the adherence of the gel is increased by this method, which can be problematic when the gilding presents a bad cohesion. sophiekirkpatrick[at] hotmail.com