Insights into the composition of ancient Egyptian red and black inks on papyri achieved by synchrotron-based microanalyses

DOI: 10.1073/pnas.2004534117

Authors: Thomas Christiansen (University of Copenhagen) , Marine Cotte (The European Synchrotron Radiation Facility; University of Sorbonne, Pierre and Marie Curie University Paris 06, CNRS) , Wout De Nolf (The European Synchrotron Radiation Facility) , Elouan Mouro (The European Synchrotron Radiation Facility) , Juan Reyes-herrera (The European Synchrotron Radiation Facility) , Steven De Meyer (University of Antwerp) , Frederik Vanmeert (University of Antwerp) , Nati Salvado (Polytechnic University of Catalonia) , Victor Gonzalez (Rijksmuseum) , Poul Erik Lindelof (University of Copenhagen; National Museum of Denmark) , Kell Mortensen (University of Copenhagen) , Kim Ryholt (University of Copenhagen) , Koen Janssens (University of Antwerp) , Sine Larsen (University of Copenhagen)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Proceedings Of The National Academy Of Sciences , VOL 54

State: Published (Approved)
Published: October 2020
Diamond Proposal Number(s): 23348

Abstract: 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 (Fe2O3) 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 (Pb3O4) and lead white (hydrocerussite [Pb3(CO3)2(OH)2] and/or cerussite [PbCO3]) 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.

Journal Keywords: inks; ancient Egypt; papyri; synchrotron-based; microanalyses

Subject Areas: Archaeological and Cultural Heritage, Physics


Instruments: I18-Microfocus Spectroscopy

Other Facilities: ID 21 at ESRF

Documents:
2004534117.full.pdf