iron gall ink

Iron gall ink pleading from the New York City Mayor's Court, circa 1700. (Courtesy of Geof Huth)Monis, Judah, 1683–1764. Biblical texts in Hebrew, circa 1740s? (Courtesy of Harvard University Archives, HUG 1580.7) n. an indelible ink once commonly used for writing and drawing

Notes

Iron gall inks came into widespread use by the ninth century. Such inks are acidic and can cause the underlying paper to deteriorate. They are black when fresh, but the acidic reaction with paper often turns the ink brown over time.