Work

Non-destructive analyses of iron-polyphenolic complexes for reconstructing iron-gall inks historical recipes

Year: 2025

Type: article

Abstract: Iron-gall inks (IGI) show considerable variability due to the wide range of historical recipes used in their preparation. Previous research has explored how factors such as pH and iron concentration affect IGI structure and how to detect these changes. This study focuses on variability induced by different tannins interacting with iron. Iron-polyphenolic complexes were systematically synthesized using both commercial tannins and oak gall extracts prepared following historical recipes. All starting materials were characterized via spectrophotometric assays and, for commercial tannins, infrared spectroscopy. The resulting complexes were analysed using Raman, IR, and Electron Paramagnetic Resonance spectroscopies to build a reference dataset. This enabled the identification of spectral markers offering insight into the materials used in IGI production through a non-destructive, multi-analytical approach. Finally, the method was applied to the "Black Hours" manuscript (property of the Austrian National Library) to investigate its ink composition, highlighting both the strengths and limits of the applied techniques.

Source: npj Heritage Science

DOI: 10.1038/s40494-025-01946-x

Authors: Salvatore Caterino, Iulia-Maria Caniola, Katja Sterflinger, Marc Pignitter, Federica Cappa

Institutions: Akademie der bildenden Künste Wien, University of Vienna

Language: English

Topic: Cultural Heritage Materials Analysis

Subfield: Archeology

Field: Arts and Humanities

Domain: Social Sciences

Open Access status: hybrid

Funder: Austrian Science Fund

Award: Synergetic Interaction of Writing Materials