a method for painting with a plurality of colors at least an article of manufacture , preferably a thermoplastic article of manufacture for the perfumery and cosmetic field , each color of said plurality of colors being that of a respective paint of a corresponding plurality of paints , said method comprising at least the operating steps of : a ) providing said at least an article of manufacture in a condition suitable for painting ; b ) providing a plurality of painting guns arranged in a succession in a painting tunnel and each being adapted to apply a paint of a said respective color of said plurality of colors ; c ) orienting said at least an article of manufacture with respect to said plurality of painting guns .