In a substrate having a graphic and a method for applying the graphic thereto, a non-phosphorescent material is applied to the substrate to define a non-phosphorescent region of the graphic and a phosphorescent material is applied to the substrate to define a phosphorescent region of the graphic. At least a portion of the non-phosphorescent region and at least a portion of the phosphorescent region are in overlapping relationship with each other so as to define an overlapping region of the graphic. When the overlapping region is exposed to light sufficient to cause phosphorescence of the phosphorescent region the at least a portion of the phosphorescent region phosphoresces to render the overlapping region visible in the absence of light. In another embodiment, the graphic has a non-photoluminescent region in overlapping relationship with a photoluminescent region.

 
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> Watermarking of digital image data

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