The invention relates to a transfer film (1), in particular hot-stamping film, the use of a transfer film (1), a film, a security document (2), and a method for producing a transfer film (1). Here, it is provided that the transfer film (1) comprises a transfer layer (20) detachably arranged on a carrier layer (10). The transfer layer (20) further has at least one first color layer (30) and the at least one first color layer (30) comprises at least one binder and at least first pigments, the color appearance of which changes depending on the observation angle.

The invention relates to an absorbent medium for improving the overprintability, in particular by inkjet printing, of a security element, in particular an optically variable security element, comprising a binder, at least one pigment and an in particular aqueous solvent. The invention furthermore relates to a transfer film with an absorbent layer made of such an absorbent medium as well as a method for personalizing a security element using such a transfer film.

A new concept of bi-luminescent security pigments includes lanthanide doped rare-earth compound with rare-earth free compound and its ink formulation. The unique features of this bi-luminescent security ink is that it emits two different colors when it is illuminated by using two different excitation wavelengths. This important feature makes it most suitable for printing of security codes or QR codes/security images on currency, important official documents, food and medicinal packaging etc. The prospective use of this bi-luminescent security ink provides a ground-breaking opening for easily printable, highly stable and unclonable bi-luminescent security codes for anti-counterfeiting applications.

A new concept of bi-luminescent security pigments includes lanthanide doped rare-earth compound with rare-earth free compound and its ink formulation. The unique features of this bi-luminescent security ink is that it emits two different colors when it is illuminated by using two different excitation wavelengths. This important feature makes it most suitable for printing of security codes or QR codes/security images on currency, important official documents, food and medicinal packaging etc. The prospective use of this bi-luminescent security ink provides a ground-breaking opening for easily printable, highly stable and unclonable bi-luminescent security codes for anti-counterfeiting applications.

A method of authenticating and/or identifying a security article including a first image includes superimposing at least partially the first image of the article with a second image. The second image may be produced by an electronic imager. The method further includes performing a relative movement between the first and second images so as to make it possible to observe an item of information relating to authentication and/or identification of the security article during the relative movement between the first and second images.

Disclosed herein are printable compositions that include a UV-A blocking compound, wherein the composition is free of colorants that are visible under white light or UV light. Also disclosed herein are images formed by printing the printable composition on a substrate surface, wherein the substrate surface includes one or more Uv fluorescent materials on at least a portion thereof. Also disclosed herein are methods of forming an image on a substrate including printing a selected amount of the printable composition on top of a UV fluorescent material.

A printing ink having a first fluorescent dye acting as donor and a second fluorescent dye acting as acceptor. The first fluorescent dye, upon excitation by electromagnetic radiation falling within an excitation wavelength range λ.sub.1a of the first fluorescent dye, is capable of emitting electromagnetic radiation in at least one first emission wavelength range λ.sub.1e, said first emission wavelength range λ.sub.1e of the first fluorescent dye overlapping with at least one excitation wavelength range λ.sub.2a of the second fluorescent dye, to thereby excite the second fluorescent dye to emit electromagnetic radiation in a second emission wavelength range λ.sub.2e.

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.

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.

A novel security feature for a valuable and/or security product is formed by a pattern that is formed on at least one carrier surface and has a color progression structure that is formed with a digital printing method from pattern elements arranged in a grid. The color progression structure is produced with at least two luminescence media that exhibit spectrally different luminescences. The valuable and/or security product according to the invention has one or more product carriers and at least one security feature that is arranged on or in the product carrier or carriers.