Decorative aluminum surface

Claim 1

IN A METHOD OF ORNAMENTING AND DECORATING ALUMINUM BASE METAL FROM THE CLASS CONSISTING OF ALUMINUM AND ALUMINUM BASE ALLOYS, THE IMPROVEMENT COMPRISING PROVIDING SAID METAL IN A DEAD-ANNEALED CONDITION WITH ITS GRAINS MINUTE IN SIZE, COLD-DEFORMING SAID METAL EQUIVALENT TO A REDUCTION OF APPROXIMATELY 1% TO 15% IN THICKNESS THEREOF, HEATING THE COLD-DEFORMED METAL FOR RECRYSTALLIZATION TO A TEMPERATURE OF ABOUT 600*F. TO 1150*F. FOR APPROXIMATELY TEN MINUTES TO THREE HOURS TO DEVELOP LARGE CRYSTALS IN THE METAL BODY, SAID CRYSTALS HAVING FACES OF MACROSCOPIC SIZE WHICH ARE VISIBLE ON THE METAL SURFACE AFTER ETCHING, ETCHING THE SURFACE OF SAID METAL IN AN ETCHING SOLUTION TO CLEARLY EXPOSE SAID CRYSTAL FACES AND THEIR BOUNDARIES AT SAID METAL SURFACE, MAKING THE METAL THE ANODE OF AN ELECTROLYTIC ANODIZING BATH AND FORMING A CORROSION-RESISTANT TRANSPARENT FILM OF ALUMINUM OXIDE INTEGRAL WITH THE METAL ON SAID CRYSTAL FACES AND SEALING SAID FILM TO RENDER IT NON-POROUS, WHEREBY UPON VIEWING SAID CRYSTAL FACES THROUGH SAID FILM, DIFFERENT SHADINGS ARE SEEM WHICH DIFFER FROM CRYSTAL FACE TO CRYSTAL FACE.