Background
The Library of Congress Prints and Photographs Division holds a large collection of Edo period (1615–1868) nishiki-e, Japanese multicolored woodblock prints. The sensitivities of some of the traditional woodblock ink colorants to environmental and conservation treatment factors causes numerous preservation concerns. Characterization of the colorants in these prints can help guide preservation policies, however, identification of colorants can be difficult and re-creation methodologies for reference samples have been elusive.
Research Results
Through extensive research, Gwenanne Edwards (Paper Conservator, Conservation Division) and Tana Villafana (Research Chemist, Preservation Research and Testing Division) prepared Japanese woodblock printing ink colorant samples from traditional plant, insect, and mineral sources (Figure 1). They characterized the reference samples using accessible non-invasive techniques, multimodal imaging and reflectance spectroscopy. They detailed their reproducible colorant preparation methods and characterization of these samples in an article in Heritage Science. They found that the majority of the colorants can be identified using multimodal imaging and reflectance spectroscopy as complementary methods.
Tana Villafana (foreground) and Gwenanne Edwards (background) preparing woodblock printing ink colorant samples for their research. Photo by Shawn Miller
Edwards and Villafana then investigated two impressions of an Utagawa Toyoharu (1735-1814) perspective print from the collection of the Prints and Photographs Division (Figure 2). The case study helped to further develop the analytical protocol for investigating Edo period Japanese woodblock ink colorants. As there are some visual similarities and notable differences in the colors in the two impressions, they also determined the correlation of the color palettes used in both impressions. The case study is detailed in an article in the Journal of Cultural Heritage. The study compared the colorants in the prints to reference samples. Multimodal imaging and reflectance spectroscopy were used as primary methods of characterization, while XRF and Raman spectroscopies supplemented analyses. Results indicated that the color palettes in the two impressions are similar and the visual differences are due to a wax coating on one of the prints and differing preservation histories. The study established a successful approach for the characterization of Edo period print colorants using primarily multimodal imaging and reflectance spectroscopy, while showing the limitations of the techniques. The study also emphasized the importance of characterizing these colorants to ensure their preservation.
Utagawa Toyoharu, Uki-e Sakaichō Fukiyachō kaomise yorushibai no zu (Perspective view of the theaters in Fukiyachō and Sakaichō on opening night), Prints and Photographs Division, Library of Congress. Above: FP 2 - JPD, no. 11; 1764-1772. Below: FP 2 - JPD, no. 1967; 1767-1773.
Citations
Villafana, Tana and Gwenanne Edwards. 2019. Creation and reference characterization of Edo period Japanese woodblock printing ink colorant samples using multimodal imaging and reflectance spectroscopy. Heritage Science 7 (94). https://doi.org/10.1186/s40494-019-0330-6
Edwards, Gwenanne and Tana Villafana. 2020. Multi-analytic characterization of colorants in two impressions of an Utagawa Toyoharu perspective print. Journal of Cultural Heritage 45. https://doi.org/10.1016/j.culher.2020.04.016
