Carbon-based and iron-gall inks constitute the two main classes of black writing inks. Carbon ink, considered the primary writing substance in the ancient world, contrasts with iron-gall inks, which were used by scribes during medieval times. Carbon inks are produced by suspending fine carbon particles in a water solution of a binder, while iron-gall inks result from a reaction between iron II ions and tannins.

The shift from carbon to iron-gall inks remains unclear, but it is certain that this change was a gradual process. Some researchers argue that it accompanied the transition in preferred writing support from papyrus to parchment. Others suggest that the introduction of the codex, a new form of book that replaced scrolls, played a role. A third possible reason is the need for a substantial volume of ink, which led to experimentation to produce a cheaper writing ink or adulteration of contemporary inks.

Scarce recipes, coupled with the results of scientific investigations of manuscripts from late antiquity and early medieval times, attest to a tradition of adding metallic substances to writing inks. Based on our research outcomes, we tentatively refer to this time as the transition period.

Nowadays, ink study protocols allow for the reliable recognition of the ink type based on its optical properties, the characterization of the elemental makeup with X-ray fluorescence spectroscopy, and the verification of carbon presence with Raman spectroscopy or infrared reflectography using a long-wave pass filter. However, mixtures of carbon inks and iron-gall inks also contain tannins, which cannot be identified with the aforementioned methods. For this reason, our team has improved upon the recently proposed study of inks with Atmospheric Solids Analysis Probe Mass Spectrometry (ASAP-MS)1, and proposes a new protocol for the minimally invasive identification of hydrolyzable and condensed tannins present in historic inks. This new approach marks a significant advancement in the field of historic black writing ink identification.

1Ghigo, Rabin, Buzi 2020.

The research for this project was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany´s Excellence Strategy – EXC 2176 'Understanding Written Artefacts: Material, Interaction and Transmission in Manuscript Cultures', project no. 390893796. The research was conducted within the scope of the Centre for the Study of Manuscript Cultures (CSMC) at Universität Hamburg.

{"references": ["Ghigo, T., Rabin, I. & Buzi, P. Black Egyptian inks in Late Antiquity: new insights on their manufacture and use. Archaeol Anthropol Sci 12, 70 (2020). https://doi.org/10.1007/s12520-019-00977-3"]}