This patent document discloses physical documents including metameric ink pairs. One claim recites a document comprising: a first surface; a second surface, in which the first surface comprises a first set of print structures and a second set of print structures, in which the first set of print structures and the second set of print structures collective convey an encoded signal discernable from optical scan data representing at least a first portion of the first surface, in which the first set of print structures is provided on the first surface with a first ink and the second set of print structures is provided on the first surface with a second, different ink, and in which the first ink and the second, different ink comprise a metameric pair. Of course, other claims and combinations are described as well.

An object of the present invention is to provide a thin volume hologram sheet to be embedded sufficiently resistant to a mechanical stress such as a stress including a tensile stress, a shear stress and a compression stress at the time of processing even under a heating condition, a forgery prevention paper and a card using the same. The object is achieved by providing a volume hologram sheet to be embedded comprising a volume hologram layer, and a substrate disposed only on one side surface of the volume hologram layer using an adhesion means, wherein a peeling strength of the volume hologram layer and the substrate is 25 gf/25 mm or more.

The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the invention relates to optical effect layers (OEL) showing a viewing-angle dependent optical effect, devices and processes for producing said OEL and items carrying said OEL, as well as uses of said optical effect layers as an anti-counterfeit means on documents. The OEL comprises a plurality of non-spherical magnetic or magnetizable particles, which are dispersed in a coating composition comprising a binder material, the OEL comprising two or more loop-shaped areas, being nested around a common central area that is surrounded by the innermost loop-shaped area, wherein, in each of the loop-shaped areas, at least a part of the plurality of non-spherical magnetic or magnetizable particles are oriented such that, in a cross-section perpendicular to the OEL layer and extending from the center of the central area to the outer boundary of the outermost loop-shaped area, the longest axis of the particles in each of the cross-sectional areas of the looped-shaped areas follow a tangent of either a negatively curved or a positively curved part of hypothetical ellipses or circles.

The invention relates to a datasheet (1) for integrating into a preferably book-like security and/or value document. The datasheet (1) is made of at least two stacked layers (2, 3) made of an organic polymer material. A textile (5) is arranged at least in a sub-region between the layers (2, 3) and outside of the layers (2, 3) so as to form a tab (4), and the textile (5) is at least partly coated on one or both sides and/or saturated with an organic binder (6) at least in the region between the layers (2, 3) and is bonded to the two layers (2, 3) by means of the binder (6).

A method of manufacturing a security device including: conveying a substrate web including a photosensitive film along a transport path; exposing the photosensitive film to radiation of a predetermined wavelength through a mask, wherein the mask includes a predetermined pattern of regions which are substantially opaque to radiation of the predetermined wavelength and at least semi-transparent to radiation of the predetermined wavelength, respectively; during the exposure, moving the mask alongside the substrate web along at least a portion of the transport path at substantially the same speed as the substrate web, such that there is substantially no relative movement between the mask and the substrate web; and heating the substrate web including the exposed photosensitive film. In this way, regions of the photosensitive film exposed to the radiation of the predetermined wavelength undergo an increase in optical density such that the photosensitive film displays a reproduction of the predetermined pattern.

A document which may be a security document has a thermochromic coating which may be a thermochromic ink on the substrate of the document. The ink may include several thermochromic materials which transition from various different colors to substantially clear in appearance as the ink is warmed to various temperatures. The combination of the colors of the thermochromic materials can give the document a different color at a number of different temperatures, until the coating is warmed to the highest color change point. When at or above the highest color change temperature, the coating becomes substantially transparent and the printed area assumes the color of the underlying substrate. The coating may also include non-reactive materials of yet another color that mixes with the colors of the thermochromic materials. The document may additionally include printed indicia on the substrate that are masked by the thermochromic materials at certain temperatures, and not masked by the thermochromic materials at other temperatures.

A capsule placed on a beverage bottle. The capsule includes a capsule material layer and at least two layers of security ink on the capsule material layer. Each of the at least two layers has a different chemical composition. At least one layer of the at least two layers includes a first composition having flakes exhibiting full reflection of light received at a predetermined wavelength.

Multilayered security devices comprising a patterned substrate over which a graphene-based coating has been applied.

An optically variable surface pattern is made available, having at least two partial areas with reflection elements, wherein the reflection elements of the first partial region on the one hand and the reflection elements of the second partial region on the other hand reflect impinging light in different reflection directions. The first partial region is so covered with a first glazing ink layer that a viewer, upon a change of the viewing angle at which the viewer views the optically variable surface pattern, sees the first partial region glow in a first color upon reaching a first viewing angle. The second partial region glows in a second color that is different from the first color upon reaching a second viewing angle.

The present invention relates to the field of the protection of security documents, especially banknotes, against illegal actions such as robbery or theft. In particular, the present invention relates to the field of ink compositions for producing irreversibly magnetically induced images or patterns, said inks comprising multichromal microspheres, preferably bichromal microspheres (1) that are orientable upon application of a magnetic field and that comprise at least a first portion (2) comprising one or more dyes and/or pigments and at least a second portion (3) comprising one or more magnetic or magnetizable materials, wherein said microspheres (1) comprise as the first portion a core (2) having a surface and comprising the one or more dyes and/or pigments and as the second portion a partial coating (3) covering at least a portion of the surface of said core (2) and comprising the one or more magnetic or magnetizable materials.