The impact of gallic acid on iron gall ink corrosion
- 315 Downloads
Many old manuscripts suffer from iron-gall ink corrosion, threatening our graphic heritage. Corroded papers become brown and brittle with age. The chemical reactions involved in this corrosion are relatively well known: they include both acidic hydrolysis and oxidation catalysed by free iron(II). Yet, a great variety of iron-gall ink recipes, including a wide range of constituents can be found in the literature and the visual aspect of old inks, can be very different from one inscription to another, even if they have been written on the same sheet of paper. This suggests that even if the free iron(II) plays a dominant role in the paper alteration, the contribution of other ingredients should not be neglected. For this reason, we explored the impact gallic acid may have on the corrosion mechanisms and in particular on the oxidation reactions. These investigations were carried out on laboratory probes prepared with paper sheets immersed in different solutions, all containing the same amount of iron sulphate, and different gallic acid concentrations. These probes were then artificially aged and their degradation state was evaluated by bursting strength measurements, FTIR spectrometry and Mössbauer spectrometry. All these analyses lead us to conclude that gallic acid has an influence on the iron(III)/iron(II) ratio, probably because of its reducing properties.
KeywordsGallic Acid Iron Sulphate Cotton Linter Cellulose Oxidation Sulphate Heptahydrate
Unable to display preview. Download preview PDF.
- 1.G. Banik, J.G. Neevel: Tintenfrassschäden und ihre Behandlung ed. by Fohlhammer (Stuttgart 1999) pp. 13–24 and pp. 87–112 Google Scholar
- 2.C. Remazeilles: Etude des processus de degradation des manuscripts anciens écrits à l’encre ferrogallique, PhD thesis (University of La Rochelle, France 2001) Google Scholar
- 3.C. Krekel: Tintenfrassschäden und ihre Behandlung, ed. by Fohlhammer (Stuttgart 1999) pp. 25–36 Google Scholar
- 6.C. Rémazeilles, V. Quillet, J. Bernard: 15th World Conference on Non-Destructive Testing Proc. (Rome 2000) Google Scholar
- 8.V. Rouchon-Quillet, L. Fournes, C. Remazeilles, A. Wattiaux: International Conference Chemical Technology of Wood Pulp and Paper (Bratislava, Slovak Republic 2003)Google Scholar