Provided are a near infrared absorbing fine particle dispersion liquid having an absorption ability in a near infrared region, a clear contrast, and applicable to offset printing, and a method for producing the same, an anti-counterfeit ink composition using the near infrared absorbing fine particle dispersion liquid and an anti-counterfeit printed matter using near infrared absorbing fine particles. Also provided are a near infrared absorbing fine particle dispersion liquid containing a solvent of one or more kinds selected from petroleum-based solvents; near infrared absorbing fine particles in an amount of 2 mass % or more and 25 mass % or less, selected from one or more kinds of hexaboride fine particles expressed by a general formula XBa, and a dispersant soluble in the solvent and having a fatty acid in its structure, and an anti-counterfeit ink composition containing the near infrared absorbing fine particle dispersion liquid.

Security of a printed matter is enhanced, and a visual image is made clear if a latent image formed by a coating printed on a matter to be printed for a security enhancement of the printed matter becomes the visual image. 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. The powder emits an infrared fluorescence when being irradiated with an ultraviolet excitation light. The perovskite-type oxide has a crystal lattice constant having a difference equal to or smaller than 0.002 angstrom from a theoretical crystal lattice constant of the perovskite-type oxide having a composition expressed as a composition formula of BaSnO.sub.3.

Security of a printed matter is enhanced, and a visual image is made clear if a latent image formed by a coating printed on a matter to be printed for a security enhancement of the printed matter becomes the visual image. 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. The powder emits an infrared fluorescence when being irradiated with an ultraviolet excitation light. The perovskite-type oxide has a crystal lattice constant having a difference equal to or smaller than 0.002 angstrom from a theoretical crystal lattice constant of the perovskite-type oxide having a composition expressed as a composition formula of BaSnO.sub.3.

A method is provided by the invention for making a security document comprising a thermoplastic substrate with a UV light cured printed image that is less likely to result in splitting of the ink of the UV light cured printed image during the lamination step of forming the thermoplastic substrate. The UV light cured image is applied to an interior thermoplastic layer surface of a stack of thermoplastic layers configured to form a thermoplastic substrate upon lamination of the stack and comprises numerous small sub-portions having small gaps between them sufficient to permit relative movement of individual sub-portions during lamination, the thermoplastic layer(s) from the ultraviolet light cured image to an exterior surface of the stack being sufficiently see-through that the image is visible upon viewing the security document. Alternatively, or additionally, the image is applied to an interior surface of an outermost thermoplastic layer of the stack adjacent an intermediate thermoplastic layer of the stack wherein the outermost thermoplastic layer has a higher melting point than the melting point of at least the adjacent intermediate thermoplastic layer.

A method is provided by the invention for making a security document comprising a thermoplastic substrate with a UV light cured printed image that is less likely to result in splitting of the ink of the UV light cured printed image during the lamination step of forming the thermoplastic substrate. The UV light cured image is applied to an interior thermoplastic layer surface of a stack of thermoplastic layers configured to form a thermoplastic substrate upon lamination of the stack and comprises numerous small sub-portions having small gaps between them sufficient to permit relative movement of individual sub-portions during lamination, the thermoplastic layer(s) from the ultraviolet light cured image to an exterior surface of the stack being sufficiently see-through that the image is visible upon viewing the security document. Alternatively, or additionally, the image is applied to an interior surface of an outermost thermoplastic layer of the stack adjacent an intermediate thermoplastic layer of the stack wherein the outermost thermoplastic layer has a higher melting point than the melting point of at least the adjacent intermediate thermoplastic layer.

Disclosed embodiments may relate to a time-dependent color-changing label for a product. The label may include a first layer comprising a plurality of particles, the particles comprising a time dependent color-changing material that changes color after a predetermined time period, the predetermined time period being greater than one month. The label may also include an attachment structure attaching the first layer to the product. In certain embodiments, the first layer may include a polymer, and the particles may include glass microspheres containing the time-dependent color changing material. The particles may be embedded in the polymer.

A printing system receives a print request containing patterns of marks to be printed on print media to produce printed output. A processor evaluates the print request to identify non-marking areas and identify different printing densities of the patterns of marks. The processor alters the patterns of marks to create hidden features on the printed output by adding a uniform printed background to the non-marking areas and adding different printing densities of fluorescent spots to different areas of the patterns of marks. The different printing densities of the fluorescent spots are based on the different printing densities of the patterns of marks and on the size of the hidden features. A printing device prints the print request on the print media to produce the printed output.

A printing system receives a print request containing patterns of marks to be printed on print media to produce printed output. A processor evaluates the print request to identify non-marking areas and identify different printing densities of the patterns of marks. The processor alters the patterns of marks to create hidden features on the printed output by adding a uniform printed background to the non-marking areas and adding different printing densities of fluorescent spots to different areas of the patterns of marks. The different printing densities of the fluorescent spots are based on the different printing densities of the patterns of marks and on the size of the hidden features. A printing device prints the print request on the print media to produce the printed output.

A method of printing a stealth white image includes applying a stealth ink containing a red coloring material that emits visible light at exposure to ultraviolet radiation and a green coloring material that emits visible light at exposure to ultraviolet radiation to a substrate which contains a fluorescent brightener to form the stealth white image thereon, wherein the stealth white image demonstrates an a* value of from −2.0 to 2.0 and a b* value of from −10.0 to 0 at exposure to ultraviolet radiation having a wavelength of 370 nm according to CIE 1976 L*a*b* colorimetric system.

The invention relates to a pigment particle for security applications, comprising a duromer matrix and a plurality of core particles of a thermoplastic polymer with a feature substance dissolved in the core particles embedded therein, wherein the feature substance is an organic or metalorganic substance. The invention further relates to a method for producing security pigments, for example luminescent printing pigments, by means of incorporation into a duromer matrix of thermoplastic polymer particles in which the luminescent illuminant is present respectively in dissolved form.