A method for applying a security device (e.g., a micro-optic security thread) to a fibrous web during manufacture is provided. By way of the inventive method, the security device is preferably applied onto the fibrous web at or near a couch roll or similar tool of a paper machine when the fibrous web constitutes a sufficiently consolidated, fully formed wet web. Papers made in accordance with the inventive method, when subjected to the Circulation Simulation Test, showed minimal damage at the paper/security device interface. Moreover, the surface-applied security devices showed acceptable levels of intaglio ink adhesion, and the papers had higher cross-direction (CD) tensile strength and much less show-through on opposing sides thereof.

A method for applying a security device (e.g., a micro-optic security thread) to a fibrous web during manufacture is provided. By way of the inventive method, the security device is preferably applied onto the fibrous web at or near a couch roll or similar tool of a paper machine when the fibrous web constitutes a sufficiently consolidated, fully formed wet web. Papers made in accordance with the inventive method, when subjected to the Circulation Simulation Test, showed minimal damage at the paper/security device interface. Moreover, the surface-applied security devices showed acceptable levels of intaglio ink adhesion, and the papers had higher cross-direction (CD) tensile strength and much less show-through on opposing sides thereof.

A method includes embossing a section of a micro-optic security thread at a predetermined pressure in an embossing die having a male half and a female half, the micro-optic security thread comprising a polymeric substrate having a first side and a second side, forming a web of a substrate in a paper making machine, wherein the web comprises a length of cellulosic material formed at a wet end of the paper making machine and maintained under tension between the wet end of the paper making machine and a dryer section of the paper making machine, forming a watermark feature in the substrate, and adhering the micro-optic security thread by positioning the embossed section such that the layer of icon elements contacts at least a portion of the web comprising the watermark feature.

A method includes embossing a section of a micro-optic security thread at a predetermined pressure in an embossing die having a male half and a female half, the micro-optic security thread comprising a polymeric substrate having a first side and a second side, forming a web of a substrate in a paper making machine, wherein the web comprises a length of cellulosic material formed at a wet end of the paper making machine and maintained under tension between the wet end of the paper making machine and a dryer section of the paper making machine, forming a watermark feature in the substrate, and adhering the micro-optic security thread by positioning the embossed section such that the layer of icon elements contacts at least a portion of the web comprising the watermark feature.

A semi-transparent security element which upon viewing in incident light and in transmitted light has different colors, comprises either (a) a transparent carrier substrate having a front side and a back side. The front side has a metallic layer V-a dyed in a first color, obtainable by printing technology by means of dyed metal pigments. The back side has an ink layer appearing in a second color R-a and a metallic layer R-b dyed in a first color, obtainable by printing technology by means of dyed metal pigments; or (b) a transparent carrier substrate having a front side and a back side. The front side has a semi-transparent metallic layer V-A and an ink layer appearing in a first color V-B and the back side has an ink layer R-A appearing in a second color, a semi-transparent metallic layer R-B and an ink layer R-C appearing in a first color.

A semi-transparent security element which upon viewing in incident light and in transmitted light has different colors, comprises either (a) a transparent carrier substrate having a front side and a back side. The front side has a metallic layer V-a dyed in a first color, obtainable by printing technology by means of dyed metal pigments. The back side has an ink layer appearing in a second color R-a and a metallic layer R-b dyed in a first color, obtainable by printing technology by means of dyed metal pigments; or (b) a transparent carrier substrate having a front side and a back side. The front side has a semi-transparent metallic layer V-A and an ink layer appearing in a first color V-B and the back side has an ink layer R-A appearing in a second color, a semi-transparent metallic layer R-B and an ink layer R-C appearing in a first color.

The present invention relates to a method of tagging a substrate with a covert, spectroscopically detectable security feature, wherein a liquid treatment composition comprising at least one acid is deposited onto a substrate, which comprises at least one external surface comprising a salifiable alkaline or alkaline earth compound.

The present invention relates to a method of tagging a substrate with a covert, spectroscopically detectable security feature, wherein a liquid treatment composition comprising at least one acid is deposited onto a substrate, which comprises at least one external surface comprising a salifiable alkaline or alkaline earth compound.

A method for manufacturing watermarked paper, comprising: a step of forming a first fibrous panel which comprises at least one watermark element; a step of forming a second, thin fibrous panel; a step of removal, by way of suction, of at least one portion of the second, thin fibrous panel in order to produce a localized reduction in thickness at a first face of the second, thin fibrous panel, so as to provide at least one accommodation seat intended to accommodate a security element; a step of coupling between the first fibrous panel and the face of the second, thin fibrous panel which lies opposite the first face.

A method for manufacturing watermarked paper, comprising: a step of forming a first fibrous panel which comprises at least one watermark element; a step of forming a second, thin fibrous panel; a step of removal, by way of suction, of at least one portion of the second, thin fibrous panel in order to produce a localized reduction in thickness at a first face of the second, thin fibrous panel, so as to provide at least one accommodation seat intended to accommodate a security element; a step of coupling between the first fibrous panel and the face of the second, thin fibrous panel which lies opposite the first face.