Abstract: Methods for coating a substrate are disclosed, the methods comprising providing a substrate, providing pre-formed nanoparticles of an inorganic material, providing at least one precursor of a first metal oxide, and depositing a coating on at least one surface of the substrate by contacting the surface with the precursor of the metal oxide and pre-formed nanoparticles. Also disclosed are substrates coated using such a method. The coated substrates are coloured. Preferably the metal oxide is a doped metal oxide to modify the thermal properties of the coating. The preferred nanoparticles are of platinum group metals or coinage metals.