Abstract: The present invention provides zinc-free glass frits that can be used to formulate glaze compositions that develop glossy surfaces when fired on ceramic products such as floor tile and wall tile. The zinc-free glass frits include, by weight, from about 50% to about 70% SiO2, from about 5% to about 20% CaO, from about 3% to about 15% Al2O3, up to about 20% BaO, up to about 15% B2O3, up to about 10% K2O, up to about 10% Na2O, up to about 10% ZrO2, up to about 5% MgO and up to about 5% PbO and less than 0.5% ZnO. Glaze compositions comprising the zinc-free glass frits can be fired using conventional double fast firing, single fast firing, and gres porcellanato ceramic firing cycles.

Abstract: Individual inks and an ink set for use in generating intermediate colors via the combination of separate inks applied by an ink jet printer to the glazed surface of an article, such as glazed ceramic architectural tile for example, that is to be heated to a temperature of greater than 300° C. The ink set according to the present invention includes at least three separate inks that upon heating decompose to form colored oxides or colored combinations with the materials of the glazed surface upon which they are applied. A first ink of the ink set includes a soluble cobalt complex for use in forming a cyan color. A second ink of the ink set includes a soluble gold complex for use in forming a magenta color. And, a third ink of the ink set includes a soluble transition metal complex for use in forming a yellow color. The third ink preferably includes a soluble praseodymium complex.