Guangzhou Tongcao painting in late China Qing Dynasty（1840—1912 AD）: technology revealed by Analytical Approaches

Abstract Guangzhou Tongcao painting in Qing Dynasty of China witnessed the exchange of economy, culture, art and technology between China and foreign countries, which was an important exported product in historical China. In this paper, by using Optical Stereo Microscope, Polarized Light Microscope, Scanning Electron Microscope attached Energy Dispersive Spectroscopy and micro confocal laser Raman Spectroscope, a Qing Dynasty Tongcao painting with the subject of family life of an official's female relative was analyzed. Our study revealed that: 1) the hexagonal cell morphology which was easily observed in the Tongcao pith could contain more pigments and increase the stereo sense of painting, and the cell of historical Tongcao pith had started to degrade, which indicated an urgent requirement on conservation of Tongcao painting; 2) alum was needed as the fixing agent in the preparation of pigments and the painting process; 3) both the China domestic pigments including red lead, calcite, lead white, carbon black and gamboge, and the synthetic pigments imported from Europe (synthetic ultramarine, prussian blue and emerald green) were applied in this painting, which reflected the bi-directional communication of culture and technology between China and western world. Meanwhile, the existence of synthetic ultramarine, prussian blue and emerald green was helpful to further identify the production date of this painting to late Qing Dynasty, mainly the mid-late 19th century.