Analysis of Qing Dynasty Calligraphy by Cao Hongxun

Abstract

The calligraphy on Xuan paper written by Cao Hongxun, who was a scholar at the end of the Qing Dynasty, was comprehensively characterized using various analytical techniques in order to provide support for further conservation. Fourier transform infrared (FTIR) spectroscopy was used to identify the type of oil in the stains. The color difference, acidity, microstructure and elemental composition of the paper areas with and without the oil stains were analyzed and characterized using colorimetry, pH measurements, and scanning electron microscope-energy dispersive spectrometry (SEM-EDS), respectively. Paper fibers were observed using SEM and an optical microscope after dying with Herzberg stain. The results demonstrate that the stain in this paper artifact is mineral oil and the paper was produced using softwood, paper mulberry and herb fibers. A large color difference, lower pH and changes in the carbon ratio were present in the oil stains. However, the stains did not affect the elemental composition of the paper. Overall, this study provides evidence for further conservation treatment, such as selecting proper paper and cleaning reagents for the stains.