Study of Tung Oil Content in Ancient Lacquer by Noninvasive Quantitative Methods: Near Infrared and Chemometrics

ABSTRACT

Lacquerware is a type of ancient and unique Chinese artwork that was also popular throughout Asia and Europe. The process of mixing tung oil in lacquer sap was a milestone in lacquerware history. However, the proportions of tung oil in different types of art forms are still not clear and are disputed, due to the lack of noninvasive quantitative technology. To solve this problem, tung oil and lacquer sap from different sources were used to make 140 standard samples with different ratios. A quantitative test model was built based on near-infrared spectroscopy and a partial least squares algorithm. Additionally, 14 typical Chinese ancient lacquer artworks were analyzed. The proportions of tung oil in different types of lacquerwares are discussed. All the spectral data from this study will be open to other researchers to ensure that this technology can be improved and applied to correlation research as soon as possible.

KEYWORDS:

• Lacquer
• tung oil
• noninvasive
• quantitative
• near-infrared spectroscopy
• chemometrics

Acknowledgements

Thanks to Wang Cheng-Min from Xi’an institute of raw lacquer, who provided lacquer sap materials with clear origin and high quality. Thanks to Zhang Jun, Zhang Tong, and Wang Kai-biao from the lacquer conservation studio of the Palace Museum, Beijing, China, who introduced the information about the ancient lacquer process and provided the opportunity of testing the ancient objects.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research has been supported by the National Key R&D Program of China [No. 2019YFC1520300].