A credential with one or more security features is disclosed. The disclosed credential includes a windowed security feature. The windowed security feature is taught to include a mirror element positioned in proximity with a transparent window and a first photo-luminescent feature positioned relative to the transparent window and the mirror element such that the mirror element enhances a luminescence of the first photo-luminescent feature when viewed and illuminated through the transparent window.

Described herein are tamper-evident adhesive seals for sealing articles, containers, and other enclosure in which a covert tamper evidencing agent is included in an adhesive sealing material. The presence of the covert tamper evidencing agent reveals evidence of tampering when exposed to UV light.

A security device is disclosed, comprising: a first ink (21) and a second ink (22) each arranged in respective laterally offset first and second regions of the security device, the first and second inks each comprising a respective luminescent material which both luminesce in response to irradiation at at least one excitation wavelength in the ultra-violet spectrum, the first and second inks each exhibiting substantially the same non-luminescent visible colour as one another when illuminated with visible light in the absence of the at least one excitation wavelength, and the first and second inks each exhibiting visible colours which are different from the non-luminescent visible colour and from one another when illuminated with a combination of visible light and the at least one excitation wavelength; a third ink (23) arranged in a third region of the device laterally offset from the first and second regions of the device, the third ink not luminescing in response to the at least one excitation wavelength, and the third ink exhibiting substantially the same non-luminescent visible colour as the first and second inks when illuminated with visible light in the absence of the at least one excitation wavelength; and a fourth ink (24) arranged in a masking pattern which partially overlaps one or more portions of the first ink in the first region and/or of the second ink in the second region, the fourth ink not luminescing in response to the at least one excitation wavelength, and the fourth ink exhibiting a different visible colour from the non-luminescent visible colour of the first, second and third inks when illuminated with visible light in the absence of the at least one excitation wavelength. When the security device is illuminated with visible light in the absence of the at least one excitation wavelength, the first, second and third regions together appear as one continuous pattern in the non-luminescent visible colour, the fourth ink obscuring the presence of more than one ink forming the continuous pattern, and when the security device is illuminated with a combination of visible light and the at least one excitation wavelength, the first and second regions become visibly distinct from each other and from the remainder of the continuous pattern.

A system and method for treatment of thread includes a thread printer that applies colored coatings to thread. A camera is positioned to capture images of the treated thread after it passes through an outlet of the thread printer. The system processes the images to determine whether the location of a selected segment of the treated thread corresponds to an expected location. If the actual location of the selected segment corresponds to the expected location, the system will continue instructing the thread printer to selectively apply the colored coatings to the thread according to the pattern. However, if the actual location does not correspond to the expected location, the system will modify the pattern so that thread printer adjusts the size of one or more segment to automatically account for the misalignment.

A solid fluorescence standard that can be used to calibrate and/or normalize a device (e.g., a scientific instrument) that is configured for generating and collecting fluorescence data. A fluorescence standard disclosed herein includes an adhesive (e.g., a low viscosity, substantially optically transparent, solvent-free, radiation curable adhesive, such as, but not limited to, a UV curable adhesive), and a selected quantity of fluorescent particles (e.g., quantum dots) dispersed in the adhesive. The adhesive and the fluorescent particles are mixed together and disposed in a sample well. The adhesive is then cured and solidified, which yields a solid fluorescence standard in the well.

The present invention provides photoluminescent iron-doped barium stannate materials absorbing ultraviolet (UV) light and exhibiting strong near-infrared (NIR) luminescence. Such materials exhibit increased integrated photoluminescence intensity in comparison to known BaSnO.sub.3 and iron-doped barium stannate materials, and therefore they are particularly useful for the production of photoluminescent security ink compositions and transparent covert security features with improved anti-counterfeiting resistance that can be used for protection of documents and articles against counterfeit and illegal reproduction.

The present invention relates to a method of manufacturing a substrate with an embedded, UV-visible pattern, wherein a liquid treatment composition comprising at least one acid is deposited onto a substrate, which comprises at least one optical brightener and optionally a filler, wherein the filler comprises 0 to 60 wt.-% of a salifiable alkaline or alkaline earth compound, based on the total weight of the substrate.

To provide a light-emitting medium whereby different light-emitting forms can be realized that can easily be discriminated using a normal blacklight, and to provide a forgery prevention medium and a method for determining authenticity of the light-emitting medium. A light-emitting medium provided with a substrate and a first light-emitting region and a second light-emitting region disposed on both sides of the substrate, the substrate comprising a selective transmission region for transmitting non-visible light in a first wavelength region and essentially not transmitting non-visible light in a second wavelength region different from the first wavelength region, and the first light-emitting region and the second light-emitting region emitting light when irradiated by non-visible light in the first wavelength region and also emitting light when irradiated by non-visible light in the second wavelength region.

A method of applying a pattern formed of two different materials to a pattern support layer includes: providing a die form having a surface with recesses defining the pattern; applying a first curable material to a surface first region, received in some of the first region recesses and partially filling a first region recess set; applying a second curable material to some of the surface first region, the second curable material at least partially fills the first set of the first region recesses; contacting a pattern support layer with the die form surface to cover the recesses containing both the first and second curable materials; separating the pattern support layer from the die form surface, the first and second curable materials in the covered recesses removed therefrom and retained on the pattern support layer; and curing the first and second curable materials during and/or after the second and third steps.

An upconverting pigment dispersion includes an upconverting pigment, such as a -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.