AIC's 46th Annual Meeting

This research report presents the results of a morphologic and compositional study of 4 different metal threads set-aside after a 1974-87 wet cleaning. These threads are from the ‘King’s Bed’, a late 17th century royal bed, now at Knole in Kent, England. Although the ‘King’s Bed’ is not currently in need of cleaning or restoration, analysis of the Knole House threads should help in determining the best plan for future conservation treatment. The threads were examined via SEM-EDS to confirm their elemental composition and morphology and provide an update on their condition. Multiple readings, both point and box field, were taken on each sample with an effort to sample all places that looked different (dark, light, scratched, edge, field…). The surface on the gold gilded samples was scratched and exhibited varying degrees of brightness. For these areas, multiple points on each sample were tested and the surface ‘mapped’ along lines to investigate if the composition varied between bright and dull areas or if corrosion products could be detected. Also a cross-sectional sample was prepared to investigate, if possible, the thickness of the gilded layer. Some readings at 10 and 7 kV were also attempted on the gold gilded surfaces in an effort to see if this could also give any insight into the thickness of the gilded layer. All threads were silver; one solid, and 3 with metal foil wrapped silk cores. The solid silver thread showed tooling striations indicating manufacturing by drawing, while high gold readings suggested possible gold gilding. The other treads were of cut metal foil wrapped about silk cores. However, their surface striations suggested different manufacturing methods. Attempts (including cross sections and low kV readings) were made to determine the thickness of the gold gilding while the EDS line-mapping tool helped correlate visual evidence with elemental composition. It was hoped that more information could be gleaned about corrosion products, but the threads appeared very clean, with scant evidence of either dust/dirt or Ag2S or AgCl corrosion products. No information was available on the detarnishing process 50 years ago. The very thin layers of gold gilding should be of interest as it is possible that the solid silver thread was gilded at one time. If so, this may have been removed during the previous cleaning. This SEM-EDS examination provided significant information on the manufacturing method and composition of the metal threads.