João Petisca showing seminar participants a deteriorated Asian lacquer chest.
Conservation of Asian Lacquer with João Petisca, University of Delaware Preservation Studies PhD program candidate and expert in lacquer conservation.

This seminar began with an introduction to the material and chemical properties of Asian lacquer and the common, and unique, applications.

João described the polymerization reaction that creates the highly cross-linked film. She informed us how analytical techniques (e.g. pyrolysis gas chromatography-mass spectrometry) can be used to identify lacquer species and additives. Understanding the different lacquer species and additives affects conservation treatment of the objects, especially when considering an object’s sensitivity to solvents.

The seminar included an overview of common conservation concerns, options for interventive treatment, and considerations for preventive conservation.

Detail of a cracked lacquer chest in the Winterthur Museum, Garden & Library collection.

One of the most prevalent condition issue affecting Asian lacquer is splitting, spalling, and other forms of destabilizing planar deformations. The deterioration mechanisms can be caused from exposure to light or improper storage environment. Some objects, typically those made for the tourist market, are inherently unstable. Cracking perpendicular to the wood grain may occur due to tensioning within lacquer films, but more research is needed to understand the cause of this phenomenon.

Artifacts with decorative techniques such as uncoated gilding are susceptible to abrasion. Those that are decorated by “scratching” in the motif prior to painting are more susceptible to cracking due the moisture ingress in scratched openings in the lacquer layer.

Treatment techniques discussed included mechanical cleaning, humidification alternatives when staining is a concern, consolidation, loss compensation, and varnish removal.