Systems and methods are described for securing credentials with optical security features formed by quasi-random optical characteristics (QROCs) of credential substrates. A QROC can be a pattern of substrate element locations (SELs) on the substrate that includes some SELs that differ in optical response from surrounding SELs. During manufacturing, a QROC of a substrate can be characterized, hidden by a masking layer, and associated with a substrate identifier. During personalization, personalization data can be converted into an authentication graphic formed on the substrate by de-masking portions of the masking layer according to a de-masking pattern. The graphic formation can result in a representation that manifests a predetermined optical response only when the de-masking pattern is computed with knowledge of the hidden QROC. The authentication graphic and optical response can facilitate simple human authentication of the credential without complex or expensive detection equipment.

A method for marking a product (1) with a photoluminescent mark, said mark comprising a photoluminescent portion (10) which is transparent under normal light conditions and revealed by photoluminescence under UV illumination, said mark further comprising a non photoluminescent portion (9) which is transparent under normal light conditions as well as under UV illumination, said method comprising: deposing on said product a stack, said stack comprising alternatively layers (2, 4), such as AlN, with a thickness of less than 1 micron and layers (3) of a second material, such as GaN, with a thickness of less than 10 nm; raising the transparency of said non photoluminescent portion (10) with a deposition of transparent material (6) or incorporation of ions into said non photoluminescent portions.

A method for marking a product (1) with a photoluminescent mark, said mark comprising a photoluminescent portion (10) which is transparent under normal light conditions and revealed by photoluminescence under UV illumination, said mark further comprising a non photoluminescent portion (9) which is transparent under normal light conditions as well as under UV illumination, said method comprising: deposing on said product a stack, said stack comprising alternatively layers (2, 4), such as AlN, with a thickness of less than 1 micron and layers (3) of a second material, such as GaN, with a thickness of less than 10 nm; raising the transparency of said non photoluminescent portion (10) with a deposition of transparent material (6) or incorporation of ions into said non photoluminescent portions.

A security device is provided including a first pattern of elements and a second, overlapping, pattern of elements spaced by a transparent layer, the first and second patterns in combination obstructing the passage of light transmitted to a viewer through the device to a varying degree depending on the viewing position. The first and second patterns of elements are configured such that a first region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a first tilt axis, and a second region of the device exhibits a maximum change in the degree of obstruction when the device is tilted relative to the viewer about a second tilt axis which is not parallel to the first tilt axis.

A method for changing a geometry of an edge of a portable data carrier, wherein the geometry of the edge is changed in order to work on the edge and the outer side of the data carrier proceeding from a common side, without a spatial location of the data carrier being changed.

A method for changing a geometry of an edge of a portable data carrier, wherein the geometry of the edge is changed in order to work on the edge and the outer side of the data carrier proceeding from a common side, without a spatial location of the data carrier being changed.

A chemically etched two dimensional matrix symbol is provided on a substrate. The substrate may be metal or plastic. In another embodiment, a process is described for forming a plurality of two dimensional matrix symbols at the same time in batches. The two dimensional data matrix symbol comprises a substrate, a plurality of grooves and a plurality of raised areas and a plurality of ink spots disposed in the grooves according to a predefined code. The matrix is readable by a scanning device.

A chemically etched two dimensional matrix symbol is provided on a substrate. The substrate may be metal or plastic. In another embodiment, a process is described for forming a plurality of two dimensional matrix symbols at the same time in batches. The two dimensional data matrix symbol comprises a substrate, a plurality of grooves and a plurality of raised areas and a plurality of ink spots disposed in the grooves according to a predefined code. The matrix is readable by a scanning device.

A method for the production of a multilayer body, in particular a security element, includes: a) producing a metal layer on a substrate; b) partial demetalization of the metal layer to form a first item of optical information in a first area of the multilayer body; c) applying a partial lacquer layer in a second area of the multilayer body to form a second item of optical information, wherein the partial lacquer layer extends at least partially beyond the metal layer; d) structuring the partial metal layer in the second area using the partial lacquer layer as mask.

A method for the production of a multilayer body, in particular a security element, includes: a) producing a metal layer on a substrate; b) partial demetalization of the metal layer to form a first item of optical information in a first area of the multilayer body; c) applying a partial lacquer layer in a second area of the multilayer body to form a second item of optical information, wherein the partial lacquer layer extends at least partially beyond the metal layer; d) structuring the partial metal layer in the second area using the partial lacquer layer as mask.