ḥibr (iron gall ink)

Ingredients

vitriol (iron, copper and other sulphates), iron filings, slags, nails, gall nuts, tree bark, fruits, fruit rind, leaves, gum arabic

Preparation Steps

Original Recipe Text

The iron gall ink (ḥibr) is obtained by mixing iron ions (sourced from vitriol, which is a mixture of iron, copper, and other sulphates, or from iron filings, slags, nails, and pieces of iron) with gallic acid in a water-based solvent. The organic compound (gallic acid) is sourced from gall nuts or by cooking/macerating vegetal matter rich in tannins (e.g., tree bark, fruits, rind, leaves). Gum arabic is added as a binder (p. 174). Some recipes specify adding vitriol empirically until the liquid turns black (p. 175).

Evidence

"Essentially, two Arabic terms were used to identify black inks: midād and ḥibr. The latter, ḥibr, is used to indicate iron gall inks, which are obtained by mixing iron ions with gallic acid in a water-based solvent, with the addition of a binder, normally gum arabic."

Remarks

Iron gall inks comprise 53% of the 260 formulas collected. Artificial ageing was performed in a chamber at T=80°C and RH=65% for 49 days to simulate historical book structures (p. 174, 180).