Publication Type:Journal Article
Source:Studies in Conservation, Volume 61, Number sup3, p.155-165 (2016)
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.