Abstract Dyes and pigments have been used in traditional Japanese woodblock printings in the ukiyo-e style for several centuries. However, the possible introduction of new European pigments and the extraordinary quality of the works of the later period led to take a keen interest in the analytical study of these ukiyo-e prints manufactured at the end of the 19th century. The present research discusses the analytical results of the series Bijin jūni kagetsu (“Beauties in the Twelve Months”) by Shuntei, dated in 1898–1899. Due to the characteristics of this type of artworks, diffuse reflectance spectroscopy (DRS) has been chosen as a portable, non-invasive analytical technique to identify pigments and colorants used in the woodblock prints. The analytical possibilities offered by the in-situ point-by-point DRS as a preliminary tool to better interpret hyperspectral imaging (HSI) data were highlighted. Reflectance spectra of more than 190 points sampled throughout the artwork were recorded between 360 and 740 nm, and characterised. Throughout an statistical classification of the spectral data using unsupervised pattern recognition methods, twenty-two different colour composition was confirmed. These groups of reflectance spectra were then identified according the presence of characteristic maxima, minima and inflection points in every spectrum. Some micro-samples extracted from the pigments still remained in a woodblock (used for a 20th century print) were analysed by FESEM-EDS to better interpret some reflectance spectra. Traditional Japanese pigments (like vermilion, red lead, and indigo) and synthetic materials introduced in the 18th and 19th centuries (Prussian blue, synthetic arsenic sulphides, eosin, and methyl violet or crystal violet) were identified in the Shuntei's series colours, together with some mixtures of pigments to prepare blue, green, orange and purple. Based on these twenty-two reflectance patterns, the point-by-point spectra make easier the task of interpreting the very complex HSI data, and reduce the time of treatment and interpretation required by HSI.

中文翻译：

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浮世绘晚期艺术作品中的颜色和颜料：使用原位逐点漫反射光谱对日本木版画进行解释高光谱图像的初步非侵入性研究

摘要 几个世纪以来，染料和颜料一直用于浮世绘风格的日本传统木版印刷。然而，可能引入新的欧洲颜料和后期作品的非凡品质，导致对这些 19 世纪末制造的浮世绘版画的分析研究产生了浓厚的兴趣。本研究讨论了 Shuntei 于 1898-1899 年创作的系列 Bijin jūni kagetsu（“十二个月的美人”）的分析结果。由于此类艺术品的特性，漫反射光谱 (DRS) 已被选为一种便携式、非侵入性分析技术，用于识别木刻版画中使用的颜料和着色剂。强调了原位逐点 DRS 作为更好地解释高光谱成像 (HSI) 数据的初步工具提供的分析可能性。在整个艺术品中采样的 190 多个点的反射光谱在 360 到 740 nm 之间被记录下来，并进行了表征。在使用无监督模式识别方法对光谱数据进行统计分类的过程中，确认了 22 种不同的颜色成分。然后根据每个光谱中特征最大值、最小值和拐点的存在来识别这些反射光谱组。FESEM-EDS 分析了从颜料中提取的一些微样品仍然保留在木版（用于 20 世纪印刷品）中，以更好地解释一些反射光谱。日本传统颜料（如朱红色、红铅、和靛蓝）和 18 世纪和 19 世纪引入的合成材料（普鲁士蓝、合成硫化砷、曙红和甲基紫或结晶紫）在 Shuntei 的系列颜色中被识别出来，并与一些颜料混合物一起制备蓝色、绿色、橙色和紫色。基于这 22 个反射模式，逐点光谱使解释非常复杂的 HSI 数据的任务变得更容易，并减少了 HSI 所需的处理和解释时间。