iron-gall ink

Ingredients

Iron, Copper, Zinc, Sulfur, Potassium, Gum arabic, Tannins

Preparation Steps

Original Recipe Text

The ink was composed using vitriol, which in this case included iron, copper, and zinc sulfates. Potassium presence indicates the use of tannins and gum arabic as a traditional binder. The text penned in this ink becomes almost transparent under NIR light but regains opacity under UV light, indicating the presence of tannin. (p. 44)

Evidence

"Note that the curve form of each element in the graphics follows that of iron, the main component of iron-gall ink, revealing the composition of the ink. Iron, copper, and zinc represent the vitriol used in the recipe, sulfur indicates that the ink indeed contained vitriol, i.e., a mixture of metallic sulfates, and potassium is strongly associated with the tannins and gum arabic that was traditionally used as a binder. (p. 44)"

Remarks

This sample provides evidence of iron-gall ink use in Egypt as early as the third century CE, coeval with the Coptic codex. This overturns the theory that iron-gall only accompanied the transition to skin-based writing surfaces. (p. 44)