New scientific evidence of the materials and craft of Hard yellow paper in Tang Dynasty collected by Gansu Provincial Museum

Abstract

Hard yellow paper is one of the few surviving Chinese famous paper from more than a thousand years ago. In particular, the documents found in Dunhuang are important collections in major museums around the world. Although there has been some research before, the production process is still a lot of controversy. In order to find out the development of materials and making craft, such as the fiber, dyeing and coating, 24 paper relics of Hard yellow paper in the Tang Dynasty from Gansu Provincial Museum have been observed and tested comprehensively by spectroscopy and spectrometry Most of the paper is handed down from generation to generation so they are in good condition of preservation. Raw materials and different surface coating materials of paper are observed by ultra-depth microscope surface observation. The organic composition of paper coating and fiber dyeing can also be accurately obtained by micro-infrared spectrometer and ultra-liquid chromatography-mass spectrometry. a series of new evidence has been found, which provides the possibility to solve the current questions and disputes. According to the results, the hemp, ramie and bark fibers are considered as raw materials; the raw materials of paper’s surface may contain plant glue and animal glue. Berberine, palmatine and phellodendrine are detected from fragments which were considered as the dye of paper. Finally, the Hard yellow paper will be upgraded by hammering, calendaring and surface coating in the Tang Dynasty.