Making Money is the 36th Terry Pratchett novel in the Discworld series, published in the UK on 20 September 2007. It is the second novel to feature Moist von Lipwig, and involves the Ankh-Morpork mint - specifically the introduction of paper money to the
You need amordant,something to make the dye "bite" into the material. Or at least that how the ancient people assumed it worked, so they gave it the Latin "biting" name. It's really a chemical reaction involving a metal ion in the mordant. You can treat the material with the mordant...