An optical device is formed by hot stamping a demetallized hologram to an optically variable foil or to a coating of optically variable ink. In another embodiment a hologram is hot stamped to a banknote or document printed with a color-shifting ink.

In order to create novel security features in secure and/or valuable documents, a polymer layer composite, which has at least two polymer layers that are bonded to each other in a material fit is provided. At least one surface is printed with an absorbing printed layer within a visible region in and/or on the composite located on a polymer layer of the composite. The absorbing printed layer forms at least one printed region, and all printed regions of the printed surface of the polymer layer have a total surface area of at least 50% and not more than 95%.

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.

Magnetic ink and toner compositions traditionally comprise magnetic materials in fine particulate form, either as a dry composition or a liquid suspension. Often such materials are black or dark in color. Disclosed herein are particles compositions suitable for use as inks or toners, that exhibit desirable magnetic properties, and furthermore which include particles coated so they appear white substantially white, or colored. Such compositions present new opportunities for the production of corresponding magnetic layers, when the compositions are deposited in an appropriate manner to a substrate.

High refractive index coatings having metal oxide particles are disclosed. Dispersions of metal oxide particles in solvent are also disclosed. These find use in the protection of surface relief structures. In some disclosed embodiments, the coatings or dispersions contain UV-curable resins. The coatings and dispersions find application in the field of security devices and documents and tokens incorporating security devices.

A security element for a security document comprises a first, second, third and fourth line grid which contrasts with the substrate surface, each of said grid being associated with a pattern comprising an embossed structure of the substrate. A first, second, third and fourth pattern angle differ from one another. A first security information item is coded as a first localized distribution of the first and second pattern, a second security information item is coded as a localized distribution of the third and the fourth pattern. The first and the second security information items overlap one another in the process. By disposing the first and second pattern in first grid cells and by disposing the third and fourth pattern in second grid cells and by arranging the first and second grid cells in alternating fashion, specific intensity distributions occur in different viewing directions of the security document, the intensity distributions being useful for examining the authenticity of the document.

Embodiments include articles, authentication methods and apparatus, and article manufacturing methods. An article includes a substrate with a first luminescent taggant, and an extrinsic feature with a second luminescent taggant, which is positioned proximate a portion of the article surface. The first and second taggants produce emissions in overlapping emission bands as a result of exposure to excitation energy. Above the extrinsic feature, the substrate and extrinsic feature emissions combine in the overlapping emission band to produce confounded emissions that are distinguishable from the substrate emissions taken alone. An authentication system determines whether, in a region corresponding to a substrate-only region of an authentic article, emissions having first emission characteristics are detected in the overlapping emission band. The system also determines whether, in a region corresponding to an extrinsic feature region of an authentic article, the confounded emissions are detected in the overlapping emission band.

The present invention relates to the use of non-deactivatable security compositions comprising the combination of at least two types of particles of oxide materials, where said particles have a different size and/or morphology, and where the inorganic oxide materials have at least one transition metal or one lanthanide element, and radiofrequency wave absorption properties. The invention also relates to security articles, documents or elements incorporating these compositions, as well as to a method and to a system for detection thereof.

A composite security device is provided that is made up of a first polymer film that constitutes or embodies a security feature in the form of at least one high value material, and a second polymer film that constitutes, embodies, or is coated with one or more additional security features. The first polymer film is positioned on and adhered to a surface of the second polymer film, which has a width or diameter greater than the width or diameter of the first polymer film By way of the present invention, the high value material is applied to only a part of the security device, leaving remaining parts of the device available for one or more additional materials that do not impact upon the effect of the high value material.

Magnetic pigments containing a transparent flaky homogeneously composed substrate having two parallel major surfaces and a coating containing maghemite, a process for the production of said pigments as well as their use.