Identification of Tannins in Historical Inks

Ira Rabin, Analysis of cultural assets, Bundesanstalt für Materialforschung und -prüfung (BAM), Berlin, Deutschland (ira.rabin@bam.de)
Gzegorz Nehring, Analysis Of Cultural Assets, Bundesanstalt Für Materialforschung Und -prüfung (bam), Berlin, Deutschland

While studying the transition from carbon inks of Antiquity to the iron-gall inks of the Middle Ages, we have discovered that the transition period lasted a millennium, from about the 4^th century BCE to about the 6^th century CE. This period is characterized by a great variety of inks – carbon, plant, iron-gall, and mixed inks – being used at the same time and in the same geographic locations.

Using their distinct optical properties, we can easily differentiate between carbon, plant and iron-gall inks. The first one, carbon particles dispersed in a water-soluble binder, keeps its black color at any illumination; the second one, a tannin extract, becomes transparent at illumination of about 750 nm, while the third one, an iron-gall complex, gradually loses its opacity towards the longer wavelengths, becoming transparent around 1400 nm. Adding an X-ray fluorescence analysis to our non-invasive analytic protocol for ink characterization allows us to detect and identify metals in the inks.

Non-destructive identification of tannins in mixed inks presents a serious challenge in our work. To overcome it, we have started developing a new mass-spectrometric application using electrostatic micro-sampling and atmospheric solid analysis. After the successful plausibility tests that were performed on the mock samples using atmospheric solid analysis probe (ASAP) with a Xevo G2-XS QTOF (Waters) [Ghigo, Rabin, Buzi 2020] we were able to identify tannins in historical inks. The presentation will discuss the first results and the further development of the application.

Tea Ghigo, Ira Rabin, Paola Buzi (2020), Black Egyptian Inks in Late Antiquity: New Insights on Their Manufacture and Use. Archaeol Anthropol Sci, 12, 70-84

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Short Biography of Presenting Author

Ira Rabin, professor at the Hamburg University a senior scientist at the Federal Institute of Material Research and Testing (BAM) in Berlin and the Centre for the Studies of Manuscript Cultures (CSMC) in Hamburg, Germany.

Ira Rabin studied chemistry at the Hebrew University of Jerusalem.  Between 1979 and 1983 she worked as a student and later as a staff member of the Conservation Department of the Jewish National and University Library (JNUL), with specialization paper and parchment conservation. In 1983, she returned to the Hebrew University of Jerusalem to continue her studies in physical chemistry, particularly in mass spectrometry. In 1987 she moved to Berlin, where she obtained a PhD degree in physical chemistry at the Max-Planck-Society in collaboration with the Free University. Until 2003 she worked in basic research in cluster physics in the Fritz-Haber-Institute of the Max-Planck-Society and continued her research on parchment but as a hobby. Since 2003 her main research interest has been dedicated to the Dead Sea Scrolls. Between 2005 - 2007 she worked in Israel as a scientific advisor to the Israel Antiquities Authority and the Jewish National Library. 2007 - 2010 she coordinated the international Qumran project. Currently besides conducting research dedicated to the Dead Sea Scrolls and history of black writing inks she is working towards including ink composition into description of historical manuscripts.