Patent Document ID: 20120043751
Application ID: 12805872
Patent Status: 0

Claim One:
1. A computer-based method for producing a printed authenticable daylight luminescent color halftone image, comprising the steps of (a) selecting a luminescent set of inks comprising at least one daylight luminescent ink (b) selecting an output gamut from the group of (i) luminescent gamut of halftones formed by said luminescent set of inks, (ii) non-luminescent output gamut formed by a non-luminescent set of inks, (iii) intersection of non-luminescent and luminescent output gamuts and (iv) union of non-luminescent and luminescent output gamuts; (c) mapping by computation the gamut of an input image onto said output gamut by applying a gamut mapping step selected from the set of gamut expansion and gamut reduction; (d) under a reference illuminant, establishing by computation a color to surface coverage mapping between gamut mapped colors and surface coverages of inks forming said luminescent set of inks; (e) relying on said color to surface coverage mapping, separating by computation the gamut mapped input image into ink layer color separations of said luminescent set of inks; (f) halftoning and printing said ink layer color separations, thereby obtaining said luminescent color halftone image; where said daylight luminescent color halftone image is authenticated by examining its excitation trace image under an illuminant active within its excitation wavelength range and by comparing it with a previously registered excitation trace image.