Technical investigation of 15thand 19thcentury Chinese paper currencies: Fiber use and pigment identification

Abstract

Herzberg staining, a quick and convenient tool for distinguishing non‐wood fibers from wood pulp, and Raman spectroscopy were employed to investigate three paper currencies issued under the reign of the Chinese Ming and Qing Emperors between 15thand 19thcenturies ‐da ming bao chao(AMS C‐14 Date: 1410‐1435 AD, ±1σ) from the Early Ming Dynasty (1405–1433 AD) andda qing bao chao(1859 AD) andhu bu guan piao(1854–1858 AD) from the Late Qing Dynasty (1840–1911 AD). Fiber staining and microscopic examination revealed a predominance of bast fiber from probably mulberry trees and very few cotton fibers (supposed to be environment contamination) inda ming bao chao; fibers inda qing bao chaoandhu bu guan piaoturned out to be quite pure, which are also bast fibers but very likely came from ramie and paper mulberry trees, respectively.Raman analysis of red, blue, and black pigments on the investigated paper currencies showed that: (1) The reddish seal onda ming bao chaois not a vermilion (HgS) paste, as it is traditionally assumed, but instead a red lead (or minium, Pb3O4) one. The red pigments on bothda qing bao chaoandhu bu guan piaoare vermilion (HgS). (2) Prussian blue (Fe7(CN)18⋅14‐16H2O), a Western pigment, was identified as blue on bothda qing bao chaoandhu bu guan piao. (3) The black pigment on all these three paper currencies is amorphous carbon from soot. (4) Raman analysis of evenly distributed white pigment particles among the fibers inda qing bao chaoconfirmed the use of calcium carbonate (CaCO3) as coating pigment or fillers. Both microscopic examination of stained fibers and Raman analysis allowed, for the first time, the understanding of fiber and pigment use in producing ancient Chinese paper currencies. Copyright © 2013 John Wiley & Sons, Ltd.