The invention relates to an absorbent medium for improving the overprintability, in particular by inkjet printing, of a security element, in particular an optically variable security element, comprising a binder, at least one pigment and an in particular aqueous solvent. The invention furthermore relates to a transfer film with an absorbent layer made of such an absorbent medium as well as a method for personalizing a security element using such a transfer film.

A security print medium for forming security documents therefrom, the security print medium comprising a core having opposing first and second sides. The core comprises a radiation-responsive substance distributed within the core across at least a first region of the core, the radiation-responsive substance being responsive to a predetermined input radiation by producing a predetermined output radiation. The security print medium further comprises a first encoding layer disposed on the first side of the core and a second encoding layer disposed on the second side of the core, each of the first and second encoding layers comprising an encoding material that modifies the intensity of the predetermined input radiation and/or the predetermined output radiation produced by the radiation-responsive substance transmitted through the respective encoding layer, wherein the first and second encoding layers overlap each other across the first region. The optical density of each of the first and second encoding layers varies across the first region in accordance with a predetermined pattern, the predetermined pattern defining one or more encoding features, such that when the security print medium is exposed to the predetermined input radiation, the output radiation detectable from one or each side of the security print medium varies across the first region in accordance with the one or more encoding features. The first and second encoding layers are configured such that when the security print medium is viewed in transmitted visible light, the intensity of visible light transmitted through the first encoding layer, the core and the second encoding layer in combination is uniform across the first region, such that the one or more encoding features is concealed.

A security print medium for forming security documents therefrom, the security print medium comprising a core having opposing first and second sides. The core comprises a radiation-responsive substance distributed within the core across at least a first region of the core, the radiation-responsive substance being responsive to a predetermined input radiation by producing a predetermined output radiation. The security print medium further comprises a first encoding layer disposed on the first side of the core and a second encoding layer disposed on the second side of the core, each of the first and second encoding layers comprising an encoding material that modifies the intensity of the predetermined input radiation and/or the predetermined output radiation produced by the radiation-responsive substance transmitted through the respective encoding layer, wherein the first and second encoding layers overlap each other across the first region. The optical density of each of the first and second encoding layers varies across the first region in accordance with a predetermined pattern, the predetermined pattern defining one or more encoding features, such that when the security print medium is exposed to the predetermined input radiation, the output radiation detectable from one or each side of the security print medium varies across the first region in accordance with the one or more encoding features. The first and second encoding layers are configured such that when the security print medium is viewed in transmitted visible light, the intensity of visible light transmitted through the first encoding layer, the core and the second encoding layer in combination is uniform across the first region, such that the one or more encoding features is concealed.

Security of a printed matter is enhanced, a coat printed on a matter to be printed for a security enhancement of the printed matter is printed by a normal printing process, and the coat is flattened and smoothed. A security ink pigment contains a powder. A main constituent of the powder is a perovskite-type oxide. The perovskite-type oxide has a composition expressed as a general formula of ABO.sub.3. A is mainly made of Ba. B is mainly made of Sn. A median diameter of the powder is equal to or smaller than 10 m. The powder emits infrared fluorescence when being irradiated with ultraviolet excitation light.

Disclosed is an ink comprising a transparent matrix being UV curable and heat scalable, and at least one pigment component. The ink in its UV-cured state has a peel strength in the range of about 6 to 8 N/cm, wherein this adhesiveness is achievable by means of a further lamination step under the influence of pressure and heat so that the ink acts as a hot glue. Further disclosed is a safety structure comprising a semitransparent layer being formed at least partially by the UV-cured ink, and a secure article comprising the safety structure. Further disclosed is a use of the ink for silkscreen printing.

Disclosed is an ink comprising a transparent matrix being UV curable and heat scalable, and at least one pigment component. The ink in its UV-cured state has a peel strength in the range of about 6 to 8 N/cm, wherein this adhesiveness is achievable by means of a further lamination step under the influence of pressure and heat so that the ink acts as a hot glue. Further disclosed is a safety structure comprising a semitransparent layer being formed at least partially by the UV-cured ink, and a secure article comprising the safety structure. Further disclosed is a use of the ink for silkscreen printing.

A banknote having a substrate with polymeric outer surfaces, including one or more coatings applied to at least one of the outer surfaces, at least one coating being a paper feel layer which provides a feel, substantially similar to that of a paper banknote, wherein the paper-feel layer includes tactile particles, to provide the paper-feel, and the tactile particles are conductive and/or the paper-feel layer includes conductive particles, or at least one of the or each coating includes conductive particles, to improve antistatic properties of the banknote.

A banknote having a substrate with polymeric outer surfaces, including one or more coatings applied to at least one of the outer surfaces, at least one coating being a paper feel layer which provides a feel, substantially similar to that of a paper banknote, wherein the paper-feel layer includes tactile particles, to provide the paper-feel, and the tactile particles are conductive and/or the paper-feel layer includes conductive particles, or at least one of the or each coating includes conductive particles, to improve antistatic properties of the banknote.

A system and method for automatic identification of photocopied documents is disclosed wherein the method is performed by capturing an image of a marked printed document; decoding a digital watermark embedded in the image, obtaining a mark identifier; recovering, by searching a database, at least one calibration parameter associated with the mark identifier; applying a discrete Fourier transform to the image, obtaining a frequency matrix; obtaining at least one maximum frequency value in the frequency matrix; comparing the at least one maximum frequency value with at least one calibration parameter; determining, on the basis of the comparison, if the marked printed document is an original document or a photocopied document.

A system and method for automatic identification of photocopied documents is disclosed wherein the method is performed by capturing an image of a marked printed document; decoding a digital watermark embedded in the image, obtaining a mark identifier; recovering, by searching a database, at least one calibration parameter associated with the mark identifier; applying a discrete Fourier transform to the image, obtaining a frequency matrix; obtaining at least one maximum frequency value in the frequency matrix; comparing the at least one maximum frequency value with at least one calibration parameter; determining, on the basis of the comparison, if the marked printed document is an original document or a photocopied document.