A method of using at least one nanoparticle for an anti-counterfeit application including selecting the at least one nanoparticle having a non-spherical configuration; providing the at least one nanoparticle on a substrate; providing a light to the at least one nanoparticle; determining a position of the at least one nanoparticle based on providing the light to the at least one nanoparticle; determining a color of the at least one nanoparticle based on providing the light to the at least one nanoparticle; defining a nanofingerprint based on the position and the color of the at least one nanoparticle; and recognizing the nanofingerprint.

The present invention relates to the field of security inks suitable for printing machine readable security features on substrate, security documents or articles as well as machine readable security feature made from said security inks, and security documents comprising a machine readable security feature made from said security inks. In particular, the invention provides security inks comprising one or more IR absorbing materials selected from the group consisting of crystal water-free iron(II) orthophosphates of the general formula Fe.sub.3(PO.sub.4).sub.2 and having a graftonite crystal structure, crystal water-free iron(II) metal orthophosphates, crystal water-free iron(II) metal phosphonates, crystal water-free iron(II) metal pyrophosphates, crystal water-free iron(II) metal metaphosphates of the general formula Fe.sub.aMet.sub.b(PO.sub.c).sub.d, wherein said security ink is an oxidative drying security ink, a UV-Vis curable security ink, a UV-Vis curable security ink or a combination thereof.

The present invention relates to 1,6,7,12-tetra-(2-isopropylphenoxy)-substituted perylene tetracarboxylic acid diimides of the formula (I) wherein R.sup.1 and R.sup.2 independently of each other are selected from hydrogen, C.sub.1-C.sub.24-alkyl, C.sub.1-C.sub.24-haloalkyl, C.sub.3-C.sub.24-cycloalkyl, C.sub.6-C.sub.24-aryl and C.sub.6-C.sub.24-arl-C.sub.1-C.sub.10-alkylene, where the rings of cydoalkyi, aryl, and aryl-alkylene in the three last-mentioned radicals are unsubstituted or substituted as defined in the claims and in the description. Moreover, the present invention relates to the use of said perylene compounds, in particular to the use of said perylene compound(s) in color converters, for data transmission and in security inks for security printing. The present invention also relates to the use of said color converters, to their use in lighting devices, to lighting devices comprising at least one LED and at least said color converter and to a device producing electric power upon illumination comprising a photovoltaic cell and said color converter.

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An original document is formed using a first print medium by printing a first and second monochrome patterns with a single colorant to form printed first and second regions including first and second shapes, respectively, which are devoid of the colorant. The second shapes have a smaller size and a higher frequency than the first shapes. The first and/or second regions encode information. The first and second patterns and a fluorescence of the first print medium are selected such that the first and second regions of the original document are indistinguishable to the naked eye, under both normal and ultraviolet illumination but are distinguishable, only under the ultraviolet illumination, in a copy formed by scanning the original document and printing the scanned document on a second print medium with a plurality of colorants, to reveal the encoded information.

The present invention relates to the field of security inks suitable for printing machine readable security features on substrate, security documents or articles as well as machine readable security feature made from said security inks, and security documents comprising a machine readable security feature made from said security inks. In particular, the invention provides security inks comprising one or more IR absorbing materials selected from the group consisting of crystal water-free iron(II) orthophosphates of the general formula Fe.sub.3(PO.sub.4).sub.2 and having a graftonite crystal structure, crystal water-free iron(II) metal orthophosphates, crystal water-free iron(II) metal phosphonates, crystal water-free iron(II) metal pyrophosphates, crystal water-free iron(II) metal metaphosphates of the general formula Fe.sub.aMet.sub.b(PO.sub.c).sub.d, wherein said security ink is an oxidative drying security ink, a UV-Vis curable security ink, a UV-Vis curable security ink or a combination thereof.

The invention relates to a security feature for securing value documents, comprising a chemically unstable inorganic feature substance and a stabilizing component that comprises a substance that stabilizes the feature substance, which substance has at least the same solubility in water as the feature substance to be protected and releases ions when said substance is decomposed, which ions conform to the ions of the feature substance at least in part.

The invention relates to a security feature for securing value documents, comprising a chemically unstable inorganic feature substance and a stabilizing component that comprises a substance that stabilizes the feature substance, which substance has at least the same solubility in water as the feature substance to be protected and releases ions when said substance is decomposed, which ions conform to the ions of the feature substance at least in part.

Security element comprising a first material MAT1 and a second material MAT2 formed in or on a substrate, in such a manner that areas occupied by MAT1 and MAT2 overlap partially or fully, the first material MAT1 comprising a phosphorescent pigment (donor), the second material MAT2 comprising a fluorescent dye or pigment (acceptor), wherein the phosphorescent pigment present in MAT1 is capable of emitting phosphorescence radiation in at least one first phosphorescence emission wavelength range 1e upon excitation by electromagnetic radiation falling within a phosphorescence excitation wavelength range 1a, and the fluorescent dye or pigment present in MAT2 is capable of emitting fluorescence radiation in at least one second fluorescence emission wavelength range 2e upon excitation by electromagnetic radiation falling within an fluorescence excitation wavelength range 2a of the fluorescent dye or pigment, and said first phosphorescence emission wavelength range 1e of the phosphorescent pigment present in MAT1 overlaps with the excitation wavelength range 2a of the fluorescent dye or pigment present in MAT2, so that after irradiation of the security element with electromagnetic radiation within the phosphorescence excitation wavelength range 1a the emission of fluorescence radiation in the emission wavelength range 2e is observable.

The invention relates to a security document (100) with a securing element (101) placed locally or on the entire surface of a laminated or non-laminated substrate, comprising at least a marking region composed of at least one printing ink layer containing optically variable interference pigments and fluorescent pigments and/or dyes or a printing ink layer containing optically variable interference pigments and being free of additives changing the absorption spectrum of the printing ink layer, the marking region comprising a laser marking applied by laser radiation, that is visually recognizable basing on an irreversible change of interference properties of the printing ink layer containing optically variable interference pigments and fluorescent pigments and/or dyes or printing ink layer containing optically variable interference pigments, and on a transformation, within the laser marking, of an original color demonstrating a change dependent on the observation angle into another color demonstrating no change dependent on the observation angle. Also, the invention relates to a method for producing a security document as well as the invention relates to a securing element placed on a laminated or non-laminated security document (100).

Example implementations relate to a printing an image on a substrate and printing an ultraviolet-sensitive finishing mark on the substrate using ultraviolet-sensitive ink. The ultraviolet-sensitive finishing mark can be visible under ultraviolet light.