Stabilisation of paper containing iron-gall ink with current aqueous processes

Chelating agents may stabilise iron-gall ink corrosion due to their antioxidative properties or by significant amounts of corrosive transition metals from the paper. While it is likely, that the net effect is a combination of both mechanisms, the knowledge of the prevailing one is essential for the optimisation of conservation treatments. Present research demonstrates the marked effect that the pH of the phytate solution has on the stability of paper containing iron-gall ink, as the model samples treated with the phytate solution at pH 5.0 degraded two to four times faster than those treated with a phytate solution at pH 6.2. It is believed that this was caused by the higher solubility of iron chelates with phytate at higher pH values, which resulted in a lower iron content in the treated papers. At the conditions of accelerated ageing (80(degrees)C and 65% RH), DTPA stabilised paper only slightly, when compared to that which was deacidified using only calcium bicarbonate.