| 摘要 |
A method for producing a validation mark on security paper includes printing the mark on the paper using an ink that has the same color as the paper but which has more uniform directional reflectance than the sheet of paper. That is, the dried ink is a more uniform diffuse reflector than is the paper. When the mark is illuminated by a light source located on one side of the mark, the mark appears lighter than the paper around it when viewed from the same side as the light source, but the mark appears darker than the paper around it when viewed from the side opposite the light source. An exemplary formulation is given.
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