A micro-optic security device with zonal color transitions includes a planar array of focusing elements, an image icon layer including a plurality of retaining structures, the plurality of retaining structures defining isolated volumes at a first depth within the image icon layer, a first zone of image icons, the first zone of image icons having a first predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the first predefined subset of the plurality of retaining structures contain cured pigmented material of a first color, and a second zone of image icons, the second zone of image icons including a second predefined subset of the plurality of retaining structures, wherein the isolated volumes of retaining structures of the second predefined subset of the plurality of retaining structures contain cured pigmented material of a second color, wherein the second color contrasts with the first color.

An article comprising a substrate which carries a material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e (I)
wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

An article comprising a substrate which carries a material of formula (I)
M.sup.1.sub.aM.sup.2.sub.bW.sub.cO.sub.d(P(O).sub.nR.sub.m).sub.e (I)
wherein each of M.sup.1 and M.sup.2 is independently ammonium or a metal cation; a is 0.01 to 0.5; b is 0 to 0.5; c is 1; d is 2.5 to 3; e is 0.01 to 0.75; n is 1, 2 or 3; m is 1, 2 or 3; and R is an optionally substituted hydrocarbyl group.

An optical device includes an array of lenses and a plurality of first and second segments disposed under the array of lenses. At a first viewing angle, the array of lenses presents a first image for viewing without presenting the second image for viewing, and at a second viewing angle different from the first viewing angle, the array of lenses presents for viewing the second image without presenting the first image for viewing. In some examples, individual ones of the first and second segments can comprise specular reflecting, transparent, diffusely reflecting, and/or diffusely transmissive features. In some examples, individual ones of the first and second segments can comprise transparent and non-transparent regions. Some examples can incorporate more than one region producing an optical effect.

An optical device includes an array of lenses and a plurality of first and second segments disposed under the array of lenses. At a first viewing angle, the array of lenses presents a first image for viewing without presenting the second image for viewing, and at a second viewing angle different from the first viewing angle, the array of lenses presents for viewing the second image without presenting the first image for viewing. In some examples, individual ones of the first and second segments can comprise specular reflecting, transparent, diffusely reflecting, and/or diffusely transmissive features. In some examples, individual ones of the first and second segments can comprise transparent and non-transparent regions. Some examples can incorporate more than one region producing an optical effect.

A method of providing an Optical Variable Device (OVD) and a tactile security element on a security document includes exposing the security document with a laser. The security document includes an overlay provided on a core, and the overlay includes a compound capable or releasing a gas. The OVD and the tactile security element have a metallic appearance.

An identification device according to the present invention that performs authenticity determination of an article provided with an anti-counterfeiting medium whose observed light pattern changes depending on an observation angle includes a similarity calculating unit that calculates a degree of similarity between captured image data of the anti-counterfeiting medium and reference image data; an authenticity determination unit that performs authenticity determination as to whether the anti-counterfeiting medium is genuine or not on the basis of whether the degree of similarity exceeds a predetermined threshold or not; and a match-percentage notification unit that notifies a match-percentage indicative of a degree of match between an imaging viewpoint for imaging the anti-counterfeiting medium and a reference imaging viewpoint which is predefined as the imaging viewpoint for the captured image data used for authenticity determination.

An identification device according to the present invention that performs authenticity determination of an article provided with an anti-counterfeiting medium whose observed light pattern changes depending on an observation angle includes a similarity calculating unit that calculates a degree of similarity between captured image data of the anti-counterfeiting medium and reference image data; an authenticity determination unit that performs authenticity determination as to whether the anti-counterfeiting medium is genuine or not on the basis of whether the degree of similarity exceeds a predetermined threshold or not; and a match-percentage notification unit that notifies a match-percentage indicative of a degree of match between an imaging viewpoint for imaging the anti-counterfeiting medium and a reference imaging viewpoint which is predefined as the imaging viewpoint for the captured image data used for authenticity determination.

A method of marking an article for authentication, the comprising the steps of applying an identification mark to an article, said mark comprising an array of varying sized markings, where the combination of the shape, the spatial distribution and the varying sizes of the markings imparts a distinctiveness to the identification mark recording the identification mark in a database and associating information relating to the article with the identification mark in the database, wherein comparison of the identification mark on the article and the database enables the identification mark to be associated with the information relating to the article on the database.

A method of marking an article for authentication, the comprising the steps of applying an identification mark to an article, said mark comprising an array of varying sized markings, where the combination of the shape, the spatial distribution and the varying sizes of the markings imparts a distinctiveness to the identification mark recording the identification mark in a database and associating information relating to the article with the identification mark in the database, wherein comparison of the identification mark on the article and the database enables the identification mark to be associated with the information relating to the article on the database.