A product article is prepared from a precursor article that has a substrate and a photosensitive thin film or a photosensitive thin film pattern on a supporting side. The product article have an electrically-conductive silver metal-containing film or thin film patterns, each of which contains electrically-conductive metallicsilver obtained by reduction of silver ions in the precursor article, an α-oxy carboxylate, an oxime compound, and a photosensitizer that can either reduce reducible silver ions or oxidize the α-oxy carboxylate.