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.

In order to increase the security of value or security documents 100, a multi-luminescent security element 400 is provided which contains at least one first luminescence means 510 and at least one second luminescence means 520. The first luminescence means 510 can be excited under first excitation conditions Sp-1 for the purpose of luminescence, and the second luminescence means 520 can be excited under second excitation conditions Sp-2 for the purpose of luminescence, said second excitation conditions Sp-2 differing from the first excitation conditions Sp-1. The multi-luminescent security element 400 is additionally equipped with at least one absorber means 600 which prevents an excitation of the at least one first luminescence means 510 under the second excitation conditions Sp-2 for the purpose of luminescence.

In order to increase the security of value or security documents 100, a multi-luminescent security element 400 is provided which contains at least one first luminescence means 510 and at least one second luminescence means 520. The first luminescence means 510 can be excited under first excitation conditions Sp-1 for the purpose of luminescence, and the second luminescence means 520 can be excited under second excitation conditions Sp-2 for the purpose of luminescence, said second excitation conditions Sp-2 differing from the first excitation conditions Sp-1. The multi-luminescent security element 400 is additionally equipped with at least one absorber means 600 which prevents an excitation of the at least one first luminescence means 510 under the second excitation conditions Sp-2 for the purpose of luminescence.

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.

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.

An approach for forming a multi-colored image on a substrate that includes a thermochromic material capable of producing at least two different colors is disclosed. Individually selected pixels of the thermochromic material that correspond to the image are heated to predetermined temperatures. Each predetermined temperature corresponds to a predetermined color shift of the thermochromic material. While the individually selected pixels are being heated, an area that includes the individually selected pixels is flooded with an amount of UV radiation sufficient to at least partially polymerize the thermochromic material. A color of each individually selected pixel is determined by a predetermined temperature to which the pixel is heated and the amount of UV radiation to which the pixel is exposed.

A security element for securing value documents comprises a first polymer containing a feature substance, which is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer which, at an elevated pH value and at elevated ambient temperature at a treatment duration of less than 60 minutes can be converted into a hydrophilic, water-soluble polymer. The security elements also contains a second polymer, which is a hydrophilic, water-soluble polymer, wherein the elevated pH value is greater than 12 and the elevated ambient temperature is greater than 90 C.

A security element for securing value documents comprises a first polymer containing a feature substance, which is at least partially surrounded by a second polymer, wherein the first polymer is a hydrophobic, water-insoluble polymer which, at an elevated pH value and at elevated ambient temperature at a treatment duration of less than 60 minutes can be converted into a hydrophilic, water-soluble polymer. The security elements also contains a second polymer, which is a hydrophilic, water-soluble polymer, wherein the elevated pH value is greater than 12 and the elevated ambient temperature is greater than 90 C.

An original document is formed using a first print medium by printing a first and second monochrome patterns with a single colorant to form printed first and second regions including first and second shapes, respectively, which are devoid of the colorant. The second shapes have a smaller size and a higher frequency than the first shapes. The first and/or second regions encode information. The first and second patterns and a fluorescence of the first print medium are selected such that the first and second regions of the original document are indistinguishable to the naked eye, under both normal and ultraviolet illumination but are distinguishable, only under the ultraviolet illumination, in a copy formed by scanning the original document and printing the scanned document on a second print medium with a plurality of colorants, to reveal the encoded information.

A security element (100, 101) and a value document (200, 201) having such a security element (100, 101) in the form of a strip having a first (1) and second polymer layer (2) are shown, baying a visually recognizable grid primed image (3), which is luminescent under UV radiation, between the first (1) and second layer (2), wherein the grid printed image (3) has an opacity and forms at least one imprint area (5) having a boundary contour (4) within the security element (100, 101). To increase the forgery protection, it is proposed that at least one of the two polymer layers (1, 2) have an opacity at least in the region of the boundary contour (4) of the imprint area (5) and be adapted in its opacity to the opacity of the imprint area (5), in order to diminish the visual recognizability of the boundary contour (4) of the imprint area (5) of the luminescent grid printed image (3) on the security element (100, 101).