| 摘要 |
The invention teaches a paper substrate having a laser treated area which has benefits for anti copy, copy deterrence and/or copy detection applications. The laser treatment may be in the form of a dense array of a plurality of microperforations which may or may not be visible to the naked eye or in form of fine graphics on the paper surface incorporated via partial ablations. The laser treated area serves as an authenticated field. In one aspect, the authentication field when copied on reprographic equipment reproduces as a field of dark separated dots. The authentication field optionally can take the form of various shapes including alphanumeric characters or other patterns. In an alternate aspect the laser treated area is an area of laser-formed partial ablations creating a synthetic watermark.
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