IMPROVING AQUEOUS INK DURABILITY DEPOSITED ON SUBSTRATE

A method for improving durability of aqueous ink deposited on a substrate having multivalent metal salt present at the surface of the substrate is disclosed. The method includes depositing aqueous ink on the surface of the substrate, wherein the aqueous ink is an anionically stabilized pigment ink, drying the substrate to substantially remove the water from the deposited aqueous ink, applying substantially pure water and heat to the dried substrate with deposited aqueous ink, and removing the applied water and heat to return the dried substrate to an ambient temperature and moisture content. The applied substantially pure water and heat are sufficient to cause a significant improvement of the durability of the deposited ink on the substrate.