Ink papyrus simulator11/12/2023 ![]() In order to quantitatively determine the ink composition, XRF results were simulated by means of Monte Carlo calculations 24, 25, 26. The qualitative comparison of these two spectra reveals an increased concentration in Pb, Al and P in the written area, which is also observable on the XRF map ( Supplementary Figure S1). From this map, two average XRF spectra were extracted, by summing the pixel spectra corresponding to i) the writing using K-means clustering 23 and visually comparing the clusters to the XRF distribution images, ii) the papyrus alone, excluding the written areas. 1B) as the writing, faintly visible in Fig. , the XRF map of Pb perfectly matches with the ink distribution ( Fig. In order to have a good statistic record of XRF data in and out of the ink, XRF 2D maps were acquired over the full surface of the samples, with a sub-millimetre beam. ![]() Accordingly, macro and micro XRF and X-ray absorption spectroscopy (XAS) techniques were used, at ID21 21 and BM26A 22 of the European Synchrotron Radiation Facility (Grenoble, France). Besides, the heterogeneity of the samples at both micro- and millimetric scales motivated the implementation of a multi-scale analysis. In terms of analytical techniques, considering the precious nature of the samples, priority was given to non-destructive imaging methods. A picture of the large sample is shown in Fig. The two fragments are flat pieces of papyrus, made of different sheets and presenting E, Π, Ι, N, Ι, Α and O, Λ letters on their surface, respectively. To be able to (dis)prove these hypotheses, two fragments (referred to as the “large” and “small” fragments) from unrolled scrolls were investigated. Furthermore, the use of a lipid-based ink to draft the papyrus writing can be hypothesized 8, 19, 20. The use of litharge (PbO) as oil drier is already mentioned by Galen at the 2 nd C. Additionally, Pb could originate from a binding medium in the ink: Pb compounds have been used extensively as dryers in paintings as they speed up the process of oil drying 15, 16. Galena has been proposed as a pigment in black inks in Egyptian papyrus before 12, whereas minium (Pb 2 2+Pb 4+O 4) has been reported as a red pigment in Roman writing 13, 14. Lead-based pigments, being a black mineral galena (PbS) or lead white (different mixtures of cerusite (PbCO 3) and hydrocerusite (2PbCO 3,Pb(OH) 2)), were frequently used in ancient times as a pigment for cosmetic products 9, 10, 11. Alternatively, Pb could have been knowingly introduced to the ink in a controlled fashion. ![]() A second hypothesis states that Pb could be present as a contaminant from a bronze container in which the ink was stored, as discussed by Canevali et al. An initial hypothesis is Pb contamination of the water used as a solvent for the ink. Lead could have been introduced unknowingly, or on purpose. Several hypotheses to explain the presence of Pb and other elements in the sample are assessed using a sequence of non-destructive, X-ray based analytical techniques, providing further insights in the production and history of the Herculaneum manuscripts. showed the presence of lead in the papyrus writing, rendering the text more readable when monitoring the Pb X-ray fluorescence (XRF) signal. The readability of the text is however not optimal due to interference of the papyrus fibres, running vertically and horizontally across the document. These attempts, however, usually led to the irretrievable loss of large parts of the text due to the brittle nature of the carbonized scrolls.Īs demonstrated by the work of Mocella et al., the writing in the scrolls can now be, at least partially, recovered by non-destructive X-ray imaging methods, without the need of unrolling the scrolls 1. Previously, it was attempted to read these scrolls by mechanically unrolling them 7. Due to the pyroclastic events associated with the eruption, the scrolls were carbonized and locked-up, rendering the writing on the scrolls unreadable. This is the only library passed on from Antiquity and is therefore an inestimable treasure. This library was discovered between 17 in the small city of Herculaneum, which was covered and preserved by layers of volcanic material in 79 AD 3, 4, 5, 6. These scrolls are part of a complete library, containing hundreds of such papyrus scrolls. Recently, the writing in rolled Herculaneum papyri was successfully explored by X-ray phase-contrast tomography 1, 2.
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