The present invention firstly relates to a security feature for a security or value document. The security feature comprises a zinc sulfide lurninophore in the form of particles. The zinc sulfide lurninophore has the general chemical formula ZnS: Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0 < x < 0.002 and 0 ≤ y < 0.00015 and 0 ≤ z < 0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100° C. and 150° C., the zinc sulfide luminophore emits a second radiation in the light spectrum. Furthermore, the invention relates to a security and value document, which may for example be a bank note or a passport, an identity card, a driving license or a postage stamp. The invention also relates to a method for detecting and/or verifying the security feature according to the invention.

The invention relates to an apparatus and a method for checking value documents marked with feature substances, and to the corresponding feature substances. The feature substances are detected on the basis of Raman or SERS spectroscopy also at high transport speeds with a spatial resolution in the low millimeter region or better and reliably identified.

The invention relates to an apparatus and a method for checking value documents marked with feature substances, and to the corresponding feature substances. The feature substances are detected on the basis of Raman or SERS spectroscopy also at high transport speeds with a spatial resolution in the low millimeter region or better and reliably identified.

A composition including a first color shifting pigment having a first color shift that extends from a starting color at normal through a plurality of colors as a viewing angle is increased to a final color, wherein the first color shift rotates counterclockwise relative to, and about, an origin of the L*a*b* color space; and a color filter that transmits a portion of the first color shift of the first color shifting pigment and absorbs a remainder of the first color shift of the first color shifting pigment; wherein the composition has a second color shift different from the first color shift; and wherein the second color shift has a first portion that rotates counterclockwise relative to the origin and a second portion that rotates clockwise relative to the origin is disclosed. A security device including the composition is included. A method of making the composition and a method of authenticating the security device are also disclosed.

Methods and apparatus for invisible luminescent protection for financial and identification documents are described herein. An example apparatus includes an illuminating source to illuminate a sample with light having a first wavelength, a photo element to detect light having a second wavelength and to capture an image of a first pattern printed on the sample, wherein the first pattern is printed on a first area of the sample with clear ink containing inorganic, ceramic particles having a mean diameter of less than one micron and having luminescent properties such that when the particles are illuminated with light having the first wavelength, they emit light having the second wavelength.

An apparatus detects a transient thermal gradient in a substrate. The apparatus is comprised of an electromagnetic radiation source configured to emit source electromagnetic radiation; a fast shutter configured to block the source electromagnetic radiation when closed, and open in response to a command to pulse the source electromagnetic radiation; a substrate support that supports a substrate disposed to emit a pulsed radiation from a back side of the substrate when the source electromagnetic radiation is pulsed through the substrate; and a detector configured to face the back side of the substrate. The detector is used to detect a transient thermal gradient in the pulsed radiation.

A system and associated method, the system including an item including a substrate including a polymer material and a first diffraction feature configured to diffract incident radiation into the substrate at an angle greater than the critical angle and launch the incident radiation into a waveguide transmission mode within the substrate to transmit the incident radiation laterally within the substrate, and a computing device including a radiation source configured to irradiate the item at a location of the first diffraction feature directly or indirectly on or within the substrate such that radiation is transmitted laterally within the substrate and a camera configured to measure emitted radiation from the substrate after lateral transmission of the incident radiation, where, in connection with irradiating with the radiation source and measuring the emitted radiation with the camera, the computing device is disposed in contact with the substrate.

A system and associated method, the system including an item including a substrate including a polymer material and a first diffraction feature configured to diffract incident radiation into the substrate at an angle greater than the critical angle and launch the incident radiation into a waveguide transmission mode within the substrate to transmit the incident radiation laterally within the substrate, and a computing device including a radiation source configured to irradiate the item at a location of the first diffraction feature directly or indirectly on or within the substrate such that radiation is transmitted laterally within the substrate and a camera configured to measure emitted radiation from the substrate after lateral transmission of the incident radiation, where, in connection with irradiating with the radiation source and measuring the emitted radiation with the camera, the computing device is disposed in contact with the substrate.

A document forgery detection method comprising using at least one processor for providing at least one histogram of gray level values occurring in at least a portion of at least one channel of an image assumed to represent a document including text, the histogram having been generated by image processing at least a portion of at least one channel of an image assumed to represent a document including text, the image having been sent by a remote end user to an online service over a computer network, evaluating monotony of at least a portion of the at least one histogram; and determining whether the image is authentic or forged based on at least one output of the evaluating.

A method and system for authenticating an item includes providing the item including a polymer substrate comprising a polymer material and a doping material, the polymer material and the doping material configured to transmit radiation laterally through the polymer substrate, and the doping material capable of scattering radiation and absorbing radiation of at least one specific wavelength to generate a spectral signature in a spectral band of wavelengths of the transmitted radiation, irradiating the item with incident radiation characterized by a spectral band of wavelengths spanning a band of wavelengths including the at least one specific wavelength absorbed and scattered by the doping material, detecting the spectral signature after the radiation is transmitted laterally through the polymer substrate, and determining a code associated with the spectral signature.