Iron-gall inks: a review of their degradation mechanisms and conservation treatments

Heritage Science

Table 1 Summary of the main results obtained in [14] for the analysis of two historic inks

Sample M03 (18th c.)	Sample C04 (18th c.)

Large brown halos; paper was very fragile but could be manipulated	Degradation of the cellulose in the inked areas led to paper crumbling
≈ 90% Fe^{2+ [§]}	≈ 90% Fe^{3+ [§]}
≈ 90% Fe²⁺ and ≈ 10% Fe^{3+ [#]}	≈ 100% Fe^{2+ [#]}

^§Mössbauer analysis in dried residues containing inked and non-inked areas
^#Calibration curve measured Fe²⁺/Fe³⁺ ratio in solution, measured in an electrochemical cell