The present invention relates to security, or decorative elements, comprising a transparent, or translucent substrate, which may contain indicia or other visible features in or on its surface, and on at least part of the substrate surface, a first layer, comprising transition metal particles having an average diameter of from 5 nm to 500 nm and a binder, on at least part of the first layer a second layer, comprising an organic material and having a refractive index of from 1.2 to 2.3 and having a thickness of from 20 to 1000 nm, wherein the transition metal is silver, copper, gold and palladium, wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 20:1 to 1:2 in case the binder is a polymeric binder, or wherein the weight ratio of transition metal particles to binder in the first layer is in the range from 5:1 to 1:15 in case the binder is an UV curable binder. The security or decorative element show a certain color in transmission and a different color in reflection and a color flop on the coating side. The color in reflection and the color flop of the security or decorative elements are controlled by adjusting the refractive index and thickness of the second layer.

Examples described herein relate to a system consistent with the disclosure. For instance, the system may comprise a printing device including hardware to form an image on a print medium, a memory resource, and a controller to receive a print job to form the markings on the print medium, designate a pixel of the received print job to form a covert dot pattern on the markings, where the pixel corresponds to a first laser intensity level; and adjust a laser intensity of the printing device to a second laser intensity level based on the first laser intensity level of the designated pixel to form the covert dot pattern.

A security marking has a physically unclonable function (PUF) wherein the PUF includes a disordered multilayer photonic crystal structure having an electromagnetic transmission and/or reflection spectrum and/or spectra upon receipt of electromagnetic radiation within a photonic bandgap region of the structure that is unique to the structure.

A multilayered printed matter includes a group of print layers formed on a medium. The group of layers include a front layer and a back layer on which patterns are printed, a white layer, and a black layer. The white layer is interposed between the front layer and the back layer to conceal the back layer to be invisible from the side of the front layer. The white layer reflects incident light from the side of the front layer to allow the front layer to be visible from the side of the front layer. The black layer is interposed between the white layer and the back layer to conceal the back layer to be invisible from the side of the front layer. In comparison between the black layer and the white layer that are equal in thickness, the black layer exerts a higher light blocking effect than the white layer.

A feature value such as a grayscale value is extracted from a design pattern on which a moiré image is based. Then, an aperture/non-aperture ratio of a moiré pattern is set according to the feature value, taking into account the specification of layers desired for a moiré image, setting of a basic pattern, and information regarding a moiré display. In addition to the aperture/non-aperture ratio, a phase shift amount and a pitch ratio can be further added to efficiently produce a moiré image having a beautiful appearance and excellent design. Moreover, such a method for generating a moiré pattern can be incorporated in a system to further improve production efficiency.

Micro-structures are formed within multilayer laminate security documents by embossing and/or debossing one or more thermoplastic layers prior to lamination of the layers. The embossed and/or debossed structures are arranged and/or formed in a way that creates a number of different security features, including a watermark formed by a relief micro-structure pattern on an opaque film (layer), a multi-color optically variable device, a 3-dimensional feature over kinegram/metallic ink and/or embossment/debossment over printed surfaces.

Micro-structures are formed within multilayer laminate security documents by embossing and/or debossing one or more thermoplastic layers prior to lamination of the layers. The embossed and/or debossed structures are arranged and/or formed in a way that creates a number of different security features, including a watermark formed by a relief micro-structure pattern on an opaque film (layer), a multi-color optically variable device, a 3-dimensional feature over kinegram/metallic ink and/or embossment/debossment over printed surfaces.

A security element and a value document having such a security element in the form of a strip having a first and second polymer layer are shown, having a visually recognizable halftone printed image, which is luminescent under UV radiation, between the first and second layer, wherein the halftone printed image has an opacity and forms at least one imprint area having a boundary contour within the security element. To increase the forgery protection, it is proposed that at least one of the two polymer layers have an opacity at least in the region of the boundary contour of the imprint area and be adapted in its opacity to the opacity of the imprint area, in order to diminish the visual recognizability of the boundary contour of the imprint area of the luminescent halftone printed image on the security element.

A security element and a value document having such a security element in the form of a strip having a first and second polymer layer are shown, having a visually recognizable halftone printed image, which is luminescent under UV radiation, between the first and second layer, wherein the halftone printed image has an opacity and forms at least one imprint area having a boundary contour within the security element. To increase the forgery protection, it is proposed that at least one of the two polymer layers have an opacity at least in the region of the boundary contour of the imprint area and be adapted in its opacity to the opacity of the imprint area, in order to diminish the visual recognizability of the boundary contour of the imprint area of the luminescent halftone printed image on the security element.

The invention relates to securing of an article against forgery and falsifying of its associated data, and particularly of data relating to its belonging to a specific batch of articles, while allowing offline or online checking of the authenticity of a secured article and conformity of its associated data with respect to that of a genuine article.