A combination of techniques to study Chinese traditional Lajian paper

Abstract

Abstract Although it is a very important Chinese traditional handmade paper, the technique employed to produce Lajian paper has been lost. Unambiguous characterization of this unique paper is essential for its conservation and reservation. A fragment of ancient purple-red Lajian paper, dated from the Qing Dynasty and decorated with flecked Au, was analyzed via non-destructive and/or micro-destructive methods, such as Optical microscopy (OM), SEM-EDS, X-ray Fluorescence spectrometry (XRF), FTIR, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, surface-enhanced Raman spectroscopy (SERS). The results showed that the Lajian paper, which was 50–60 μm thick overall, was produced from bamboo fibers that were mixed mainly with wheat and mulberry fibers. The front surface was first filled with kaolin to form a coating that was approximately 10 μm thick and then polished with wax mixed with cochineal dye, minium pigment and animal glue to form a purple-red color to protect it from humidity and mold growth. The back surface was treated the same as the front, except that cochineal was not used. The handmade paper and color were stable because cochineal produced neutral/weak alkaline conditions. This study provides comprehensive information about the production process of this traditional handmade paper.