Color changing effects with cross-halftone prints on metal

We propose new methods for creating color varying prints with classical cyan, magenta, yellow inks on a metallic substrate. We use a special crossline halftone with optimized surface coverages of the inks to create color prints on a metallic surface whose colors change when rotating the print in-plane under specular reflection. These prints enable viewing on the same metallic print a first image with a first set of colors and upon in-plane rotation, the same image with parts colored with a different set of colors. They also enable viewing a first color image and upon rotation a second independent color image. Applications comprise counterfeit prevention, art, advertisement exhibitions and amusement parks.