The invention generally relates to a security sheet or document having one or more enhanced watermarks. In one exemplary embodiment, the inventive security sheet or document is a single-ply paper that is made up of a paper layer including one or more watermarks, and a micro-optic security device (e.g., a patch or thread) that at least partially covers an upper or face portion of the watermark(s). The overlying patch or thread increases the durability of the watermark(s), thereby allowing for the watermark(s) as well as reduced fiber density areas therein to be made larger, and further allowing for the reduced fiber density areas to be made thinner. In a preferred embodiment, the micro-optic security device projects one or more synthetic images that coordinate or link in with the watermark design(s). In a more preferred embodiment, the micro-optic security device offers a machine detectable/readable feature in the form of enhanced IR-brightness, especially when measured in transmission. As will be readily appreciated, the inventive security sheet or document offers greatly improved counterfeit-resistance.

The invention generally relates to a security sheet or document having one or more enhanced watermarks. In one exemplary embodiment, the inventive security sheet or document is a single-ply paper that is made up of a paper layer including one or more watermarks, and a micro-optic security device (e.g., a patch or thread) that at least partially covers an upper or face portion of the watermark(s). The overlying patch or thread increases the durability of the watermark(s), thereby allowing for the watermark(s) as well as reduced fiber density areas therein to be made larger, and further allowing for the reduced fiber density areas to be made thinner. In a preferred embodiment, the micro-optic security device projects one or more synthetic images that coordinate or link in with the watermark design(s). In a more preferred embodiment, the micro-optic security device offers a machine detectable/readable feature in the form of enhanced IR-brightness, especially when measured in transmission. As will be readily appreciated, the inventive security sheet or document offers greatly improved counterfeit-resistance.

A method and a device are disclosed for luminous printing of an original image using fluorescent ink or other fluorescent display pigments. In some embodiments, the original image is separated into multiple layers, including at least a brightness layer and an inverse brightness (or darkness) layer, by applying extracted brightness data and inverse brightness data, to the original image, respectively. Each of the layers is associated with a set of corresponding printing channels. The sets of printing channels are applied by a printing device to print the original image on a print medium, such as paper, mylar, fabric, and other print surfaces. Multiple visual effects may be realized using the aforementioned process, including fluorescent images that are only visible under UV (Ultra Violet) or black light, images with high-fidelity colors under daylight and dark conditions, and shadow effects such as depth illusion.

A printing method is provided. In this printing method, a printing ink composed of pigment-based solvent UV ink or UV ink is applied onto a transfer sheet capable of transmitting an ultraviolet light, and then the printing ink is cured to form a printing ink layer. Thereafter, a bonding ink composed of solvent UV ink or UV ink for bonding the printing ink layer to a medium is applied onto the printing ink layer. Subsequently, the bonding ink is pressed against the medium. In this state, irradiation with the ultraviolet light from an opposite surface of the transfer sheet to a surface having the printing ink layer formed thereon is performed, such that the bonding ink is completely cured to form a bonding ink layer. Thereafter, the transfer sheet is peeled off from the printing ink layer, whereby the printing ink layer is transferred onto the medium.

A printing method is provided. In this printing method, a printing ink composed of pigment-based solvent UV ink or UV ink is applied onto a transfer sheet capable of transmitting an ultraviolet light, and then the printing ink is cured to form a printing ink layer. Thereafter, a bonding ink composed of solvent UV ink or UV ink for bonding the printing ink layer to a medium is applied onto the printing ink layer. Subsequently, the bonding ink is pressed against the medium. In this state, irradiation with the ultraviolet light from an opposite surface of the transfer sheet to a surface having the printing ink layer formed thereon is performed, such that the bonding ink is completely cured to form a bonding ink layer. Thereafter, the transfer sheet is peeled off from the printing ink layer, whereby the printing ink layer is transferred onto the medium.

A document (15) includes at least: one first image (5) including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one first source (20) of non-visible light emitting in the short ultraviolet domain, one second image including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one second source of non-visible light emitting in the long ultraviolet domain, one layer, named a filtering layer, arranged facing the second image and including at least one material, named a filtering material, suitable for allowing the wavelengths emitted by the first source of non-visible light to be filtered without preventing the first image from being seen under illumination by the first light source.

A document (15) includes at least: one first image (5) including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one first source (20) of non-visible light emitting in the short ultraviolet domain, one second image including at least one photoluminescent pigment which is invisible under illumination in visible light and is visible under illumination by at least one second source of non-visible light emitting in the long ultraviolet domain, one layer, named a filtering layer, arranged facing the second image and including at least one material, named a filtering material, suitable for allowing the wavelengths emitted by the first source of non-visible light to be filtered without preventing the first image from being seen under illumination by the first light source.

The present invention relates to fluorescent compounds with large Stokes-shift and a process for their preparation. More particularly, the present invention relates to fluorescent compounds that are colourless. The compounds may be used in compositions for inks, paints and plastics, especially in a wide variety of printing systems and are particularly well-suited for security applications.

The present invention relates to fluorescent compounds with large Stokes-shift and a process for their preparation. More particularly, the present invention relates to fluorescent compounds that are colourless. The compounds may be used in compositions for inks, paints and plastics, especially in a wide variety of printing systems and are particularly well-suited for security applications.

The invention relates to a security feature for safeguarding value documents, comprising particles which are composed of at least two different, spatially separate solid homogeneous phases, wherein each of the phases is detectable and identifiable in a spatially resolved manner by means of a spatially resolving analytical method that is adapted for resolving down to the single-particle level.