In this work some luster decorated ancient ceramics have been analyzed in order to acquire knowledge about technological procedures in luster production during the Renaissance period in Italy. Luster is a thin decorative metallic film present on the surfaces of some previously glazed ancient majolicas. It was obtained by applying on the majolica surface a mixture containing silver and copper compounds. Subsequently the object was fired in a reducing atmosphere. It was found that the luster color, red-like or gold-like, depends not only on the chemical composition, determined by Inductively Coupled Plasma Emission Spectroscopy (ICP-OES), but on the dimensions of silver and copper metallic nanoparticles forming the luster too. Nanocrystals’ dimensions and structural characteristics were determined by Transmission Electron Microscopy (TEM). As obtaining a satisfactory luster depends on the composition of the underlying glaze too, the chemical composition of the glazes have been derermined and the analytical data were submitted to statistical multivariate analysis.