Egyptology Section, Department of Cross-Cultural and Regional Studies, University of Copenhagen, 2300 Copenhagen S, Denmark;
The European Synchrotron Radiation Facility, 38043 Grenoble Cedex 9, France;
Proc Natl Acad Sci U S A. 2020 Nov 10;117(45):27825-27835. doi: 10.1073/pnas.2004534117. Epub 2020 Oct 26.
A hitherto unknown composition is highlighted in the red and black inks preserved on ancient Egyptian papyri from the Roman period (circa 100 to 200 CE). Synchrotron-based macro-X-ray fluorescence (XRF) mapping brings to light the presence of iron (Fe) and lead (Pb) compounds in the majority of the red inks inscribed on 12 papyrus fragments from the Tebtunis temple library. The iron-based compounds in the inks can be assigned to ocher, notably due to the colocalization of Fe with aluminum, and the detection of hematite (FeO) by micro-X-ray diffraction. Using the same techniques together with micro-Fourier transform infrared spectroscopy, Pb is shown to be associated with fatty acid phosphate, sulfate, chloride, and carboxylate ions. Moreover, micro-XRF maps reveal a peculiar distribution and colocalization of Pb, phosphorus (P), and sulfur (S), which are present at the micrometric scale resembling diffused "coffee rings" surrounding the ocher particles imbedded in the red letters, and at the submicrometric scale concentrated in the papyrus cell walls. A similar Pb, P, and S composition was found in three black inks, suggesting that the same lead components were employed in the manufacture of carbon-based inks. Bearing in mind that pigments such as red lead (PbO) and lead white (hydrocerussite [Pb(CO)(OH)] and/or cerussite [PbCO]) were not detected, the results presented here suggest that the lead compound in the ink was used as a drier rather than as a pigment. Accordingly, the study calls for a reassessment of the composition of lead-based components in ancient Mediterranean pigments.
在来自罗马时期（约公元 100 年至 200 年）古埃及纸莎草纸的红黑墨水中，突出显示了一种迄今为止未知的成分。基于同步加速器的宏观 X 射线荧光（XRF）测绘揭示了 12 个来自泰布图尼斯神庙图书馆的纸莎草碎片上所写的红色墨水中存在铁（Fe）和铅（Pb）化合物。这些墨水中的铁基化合物可以归因于赭石，这主要是由于 Fe 与铝共定位，以及通过微 X 射线衍射检测到赤铁矿（FeO）。使用相同的技术以及微傅里叶变换红外光谱法，表明 Pb 与脂肪酸磷酸盐、硫酸盐、氯化物和羧酸盐离子有关。此外，微 XRF 图谱显示 Pb、磷（P）和硫（S）的分布和共定位具有特殊性，这些元素在微米尺度上以类似于围绕嵌入在红色字母中的赭石颗粒的扩散“咖啡环”的形式存在，并且在亚微米尺度上集中在纸莎草细胞壁中。在三种黑色墨水中也发现了类似的 Pb、P 和 S 组成，这表明在制造基于碳的墨水时使用了相同的含铅成分。考虑到没有检测到红色铅（PbO）和铅白（碱式碳酸铅[Pb(CO)(OH)]和/或碳酸铅[PbCO]）等颜料，这里的结果表明墨水中的铅化合物被用作干燥剂而不是颜料。因此，该研究呼吁重新评估古代地中海颜料中含铅成分的组成。
