Aqueous ink durability deposited on substrate

A method for improving durability of aqueous ink deposited on a substrate having multivalent metal salt present at a surface of the substrate, the method comprising, in order:

• depositing an aqueous ink on the surface of the substrate, wherein the aqueous ink is an anionically stabilized pigment ink;
• drying the substrate having the deposited aqueous ink to substantially remove the water from the deposited aqueous ink;
• applying substantially pure water and heat to the dried substrate having the deposited aqueous ink;
• and
• removing the applied water and heat to return the dried substrate having the deposited aqueous ink to an ambient temperature and moisture content, the applied moisture and heat being sufficient to cause a significant improvement of the durability of the deposited aqueous ink on the surface of the dried substrate.