Ecole Polytechnique Federale De Lausanne

Petar Pjanic

Roger David Hersch

We propose new methods for creating color varying prints with classical cyan, magenta, yellow inks on a metallic specularly reflecting or on a white diffusely reflecting substrate. We use a special cross-line halftone with optimized surface coverages of the inks to create cross-halftone prints whose colors change when rotating the print in-plane under specular reflection. These prints enable viewing at the same location a first image with a first set of colors and upon in-plane rotation of the print or displacement of the observer, a similar or a different image whose parts are colored with a different set of colors. Applications comprise counterfeit prevention, art, advertisement, decoration, exhibitions and surprising displays in amusement parks.

Color changing effects with cross-halftone prints

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.

Color changing effects with cross-halftone prints on metal

We propose new methods for creating color or achromatic images that are printed with classical cyan, magenta, yellow and a white diffusing ink on a metallic substrate. We optimize the surface coverages of the cyan, magenta, yellow and white inks in order to create color prints on a metallic surface that look bright and colorful under specular reflection and also look good under non-specular observation conditions. We also provide new means for the prevention of counterfeits. A first effect enables viewing on the same metallic print one achromatic image in specular viewing mode and a second independent achromatic image in non-specular viewing mode. The second effect enables hiding a pattern such as text, graphics or a grayscale image within the printed color image in one viewing mode, specular or non-specular and showing that pattern in the second viewing mode, non-specular or specular, respectively.

Growing community of inventors

Chavannes-près-Renens, Switzerland

Petar Pjanic