Abstract: 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.

Abstract: The invention teaches a novel paper substrate having a transparent field of a dense array of a plurality of laser-formed microperforations. The resultant paper can be useful as a replacement for glassine paper, and can be useful in secure documents. The transparent field is integral to the paper substrate and can be formed by laser techniques surprisingly resulting in a transparent field retaining acceptable strength characteristics after lasing. The transparent field acts as a self authentication device.

Abstract: A rapidly reversing authenticity indicator for substrates such as secure documents, tags and labels is described. The authenticity indicator comprises a substrate having provided thereon a coating of a colorless chromogenic material, a binder material and optional pigment. An applicator is provided containing a developer material solution for the colorless chromogen. In one embodiment, the developer material solution is preferably an organic acid of five carbons or less and is selected to have a molecular weight of 102 or less, a pH of less than 5, and preferably positive vapor pressure. The coated substrate when contacted with the developer material in the applicator develops an intense color that persists momentarily rapidly reverting to substantially a colorless or pale form to provide a visual indication of authenticity without permanent discoloration of the substrate or inadvertent coloration or undue false positives.