Science

Lacquer has a long and ongoing tradition of use in Asia. Known as qi 漆 in China, its use can be traced back to the Neolithic period and it remains in use today. The earliest known Chinese archaeological lacquered object dates to approximately 6000 bce. Many Chinese classical texts and historical documents over the last 8000 years mention lacquer and related information. An extensive investigation of Chinese literature from different time periods was carried out to search for useful information scattered throughout Chinese texts. This article outlines some of the highlights and research challenges.

This article presents a detailed case study of a red carved lacquer dish (accession number 33–575/2) inscribed with a mark of the Jiajing period (1521–1567 CE) of the Ming dynasty, currently in the collection of the Nelson-Atkins Museum of Art. Examination, analysis, and stylistic studies revealed new information regarding the material composition, manufacturing techniques, and decorative properties of the object. The analytical results were compared and contrasted with those of three other carved lacquer objects with Jiajing marks. The technical study included fluorescent light microscopy, pyrolysis–gas chromatography–mass spectrometry with thermally assisted hydrolysis and methylation, and scanning electron microscopy with energy dispersive spectroscopy. The information from the cross-disciplinary study suggests the red carved lacquer dish 33–575/2 is unlikely to be the creation of the Ming Jiajing official production. The inscription is, therefore, likely to be a spurious inscription produced from a later period.

Coromandel lacquer is a type of polychrome lacquer in which designs carved into the smooth lacquer surface are filled with painted colors. Unlike many other lacquer techniques, Coro- mandel has a relatively short history and limited written record. To gain a greater understanding of its decorative technique and material usage, extensive technical analysis has been carried out. This technical study included fluorescent light microscopy, pyrolysis-gas chromatogra- phy–mass spectrometry with thermally assisted hydrolysis, and methylation and scanning elec- tron microscopy with energy-dispersive spec- troscopy. The scientific outcomes were then compared and contrasted with the relevant historical documents. The results revealed the complex compositions of the objects studied and suggested the existence of three major Coromandel groupings.

Carved lacquer is commonly known as diaoqi 雕 漆 in Chinese. It is created from applying multiple layers of lacquer until the desired thickness is reached, after which elaborate patterns are designed and engraved into the layers using carving tools. Although red is the color commonly associated with carved lacquer, other colors have also been used. This paper aims to characterize the material components of the less noticed green and yellow layers in Chinese carved lacquer production through the study of historical documentation and scientific investigation. The technical study included fluorescent light microscopy, pyrolysis-gas chromatography-mass spectrometry with thermally assisted hydrolysis and methylation, and scanning electron microscopy with energy-dispersive spectroscopy. The scientific outcomes were then compared and contrasted with the relevant historical documents. The results revealed the usage of orpiment and indigo during production and their correlation with multiple Chinese historical records.

Three late-eighteenth-century to early-nineteenth-century objects made from Asian lacquer were analyzed using histochemical staining of cross-sections and pyrolysis-gas chromatography-mass spectrometry, and found to include laccol, and perilla oil and cedar oil, in contrast to urushiol alone, commonly used as an analytical marker for Asian lacquer. Sample set based on urushi made from laccol, and varied amounts of perilla oil and cedar oil were created and light aged in a xenon arc weatherometer, further aged in different levels of relative humidity, while physical changes were monitored by means of pH, gloss measurements, and autofluorescence during aging. The pH was dependent on initial composition. The study gave new understanding of autofluorescence in lacquers, and made clear that samples for experiments must include urushi, laccol, and thitsi, which have physical and chemical differences. The hypothesis that urushi has superior aging characteristics to laccol is not consistent with the results. The experiments also demonstrated that other ingredients constituting major additives are equally important to the behavior of lacquer as it ages.

This paper summarizes the various information that has been gathered in recent years at the J. Paul Getty Museum and Getty Conservation Institute with regard to the organic constituents of Chinese lacquer formulations. While this summary of materials is by no means comprehensive or complete, it captures the current state of the authors' knowledge, with the information itself and the bibliography intended to serve as a useful foundation from which further research may proceed. Considerable advances have been made in the last decade in the technique of pyrolysis-gas chromatography-mass spectrometry with thermally assisted hydrolysis and methylation using tetramethylammonium hydroxide and in subsequent data interpretation methodologies. These have dramatically improved the sensitivity and specificity of organic analysis. Perhaps equally important, these methodologies are allowing researchers to collaborate much more effectively and to share results that are truly comparable and reproducible. As more researchers participate and collaborate, and as more results are aggregated into shared databases, significant new insights into the methods and materials of Chinese lacquer are sure to follow.