Figure 5
From: Investigation of the stabilization of verdigris-containing rag paper by wet chemical treatments
Ca mapping on the surface of calcium hydrogen carbonate-treated samples. Left – Sample after calcium hydrogen carbonate treatment in pure water. The Ca signal was close to the background noise. Right – Sample after calcium hydrogen carbonate treatment in a mixture of water and ethanol (2:1). The overall Ca signal was still weak but relatively higher, and accumulated Ca compounds were observed.