Conservation of waterlogged archaeological corks using supercritical CO2 and treatment monitoring using structured-light 3D scanning

Archaeological waterlogged cork is one the most unpredictable archaeological materials to conserve. Over the years, various techniques designed to conserve waterlogged wood have been applied to cork with less than satisfactory results. These techniques include freeze drying with or without consolidant, air-drying and silicone oil treatment. Alternatively, recent studies demonstrated that methanol exchange followed by supercritical CO2 drying can overcome most of the limitations of the latter techniques when applied to organic waterlogged materials. In 2005, a joint research project was initiated between the Warren Lasch Conservation Center (WLCC) and Parks Canada to evaluate the use of supercritical CO2 drying on significant archaeological corks and composite artifacts from several shipwrecks. This paper will discuss the drying process of the various corks and the techniques employed to monitor their appearance and dimensions, namely conventional measurement techniques and structured-light 3D scanning combined with three-dimensional inspection.