Produced from the tannic acid of oak bark in a reaction with iron salts, it was a popular ink from the 12th to 19th century.
Manufacturer / product code: Kremer / 12030
Chemical description: synthetic ink. water-soluble ferrous tannate complex. Because of its solubility, the ink is able to penetrate the paper surface, making it difficult to erase. When exposed to oxygen a ferric tannate pigment is formed. This complex is not water-soluble, contributing to its permanence as a writing ink Kremer PDF