Ink corrosion treatment

Iron gall ink was used from antiquity to the late 19th century. This is a mixture of iron salts (iron (II)sulphate) and gall nut extracts. Iron gall ink has no colour when produced. Its characteristically dark hue appears only after the iron ions react with oxygen.

Production of this ink leads to the formation of sulphuric acid. While iron salts, a cheap resource in ink production, were added excessively, these ingredients damage the paper and cause it to lose its stability and crack. Iron gall ink can virtually eat through paper and will leave holes in the pages.


Preserving ink corrosion treatment stops this chemical degradation process. The excessive iron salts in the ink are removed or chemically deactivated. Both the acids in the ink and the paper are neutralised.
If pages are already missing bits, further restoration is required. Light paper damage permits stabilising the entire sheet or damaged areas with a wafer-thin, transparent sheet of Japanese tissue paper. Strongly damaged paper is stabilised by splitting or leaf-casting of the sheet. Alternatively, we can embed strongly damaged paper in Japanese tissue paper.