A security device including an array of lines printed or otherwise provided on a substrate, the lines including materials which have the same appearance under visible light illumination but which appear different from each other in the visible under a combination of visible and non-visible, ultraviolet illumination. At least some of the lines in the array appear different from other lines under the combination of visible and non-visible, ultraviolet illumination. A second, surface relief array of lines imposed on the first array, the orientation, line widths and spacings of the first and second arrays being such that the device exhibits a variable appearance as it is tilted while exposed to the combination of visible and non-visible illumination.

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.

A microcapsule, method, and article of manufacture are disclosed. The microcapsule includes an outer shell, a molecular sensitizer, a molecular annihilator, and an inner shell separating the molecular sensitizer from the molecular annihilator. The method includes forming microcapsules, each microcapsule having an outer shell, a molecular sensitizer, a molecular annihilator, and an inner shell separating the molecular sensitizer from the molecular annihilator. The article of manufacture includes at least one of the microcapsules.

Example implementations relate to a printing an image on a substrate and printing an ultraviolet-sensitive finishing mark on the substrate using ultraviolet-sensitive ink. The ultraviolet-sensitive finishing mark can be visible under ultraviolet light.

The present invention relates to the use of nanosystems as non deactivable security markers comprising metal atomic quantum clusters (AQCs) of at least two different size distributions encapsulated in a cavity with an inner diameter less than or equal to approximately 10 nm. These nanosystems are luminescence, particularly fluorescence after external excitation. The invention also relates to security documents, articles or elements incorporating these markers as well as to a method and a system for detecting the same.

There is provided a luminescent medium which requires difficult analysis of light emitted from a luminescent material of the medium. A luminescent medium 10 includes a substrate 11, and a luminescent material 12 comprising a first luminescent material 12A which, when irradiated with visible light, infrared light or ultraviolet light, emits first infrared light “a”, and a second luminescent material 12B which, when irradiated with visible light, infrared light or ultraviolet light, emits second infrared light “b”. The first luminescent material 12A is formed in a first planar area 11A, and the second luminescent material 12B is formed in a second planar area 11B. The first planar area 11A and the second planar area 11B overlap each other, forming an overlapping planar area 11C in which the luminescent materials 12A and 12B each have a concentration gradation.

An upconverting pigment dispersion includes an upconverting pigment, such as a β-NaYF.sub.4 crystal doped with at least one of Erbium, Ytterbium or Thulium. The upconverting pigment dispersion is aqueous. Upconverting inkjet ink is made by mixing the crystals with a polymer dispersant and water and milling the mixture until the crystal particles are between 50 nanometers and 200 nanometers. Deionized water, a colorant and a humectant are added to the milled mixture.

A laser-assisted method embeds luminescent taggant particles in the surface of a substrate to provide a covert method of evaluating the authenticity of articles so treated.

A device and a method that achieve a watermark that can be easily recorded and does not significantly impair the appearance of a printed matter are provided. A watermark recording unit (214) that records watermark dots having a color having a small difference from an area color of an area in which a watermark is recorded, and a watermark recording mode determination unit (213) that determines a color of the watermark dots are included. The watermark recording mode determination unit (213) determines a color of the watermark dots in such a way that a wavelength difference Δλ, which is a difference between a color wavelength of the watermark dots and an area color wavelength of a recording area of the watermark dots, is less than a wavelength resolution of human eye. Moreover, the color of the watermark dots is determined in such a way that the wavelength difference Δλ is equal to or higher than a wavelength resolution of a spectroscopic camera (hyperspectral camera) (141) that captures an image for watermark analysis.

A digital printing press for printing security documents is provided. The digital printing press comprises: a first digital print head, the first digital printhead comprising a first array of print nozzles having a first nozzle diameter; a second digital print head, the second digital print head comprising a second array of print nozzles having a second nozzle diameter different from the first nozzle diameter; optionally, an offset printing unit, the offset printing unit comprising one or more offset printing surfaces, wherein the offset printing unit is adapted to transport a print area of the one or more offset printing surfaces sequentially past each of the first and second digital print heads, and subsequently to transfer print received from the first and second digital print heads to a security document substrate; a transport system adapted to transport a security document substrate along a transport path through the digital printing press, wherein either the transport path takes the security document sequentially past each of the first and second digital print heads in a feed direction, or the transport path takes the security document substrate past the offset printing unit, if provided, in a feed direction; a controller adapted to control both the first and second digital print heads to execute a set of printing instructions so as to print on a security document substrate transported past the first and second digital print heads by the transport system or to print on the print area of the one or more offset printing surfaces transported past the first and second digital print heads by the offset printing unit (and to transfer the print received on the print area of the offset printing to the security document substrate), the set of printing instructions including printing instructions at a first resolution for the first digital print head for printing a first print working and printing instructions at a second resolution different from the first resolution for the second digital print head for printing a second print working; wherein the first digital print head is configured to print at the first resolution and the second digital print head is configured to print at the second resolution, and wherein the first and second digital print heads are configured or controlled by the controller to remain static relative to the transport path or offset printing unit while the first and second digital print heads execute the respective printing instructions.