A method for enhancing the structural strength of a porous substrate having pores therein is disclosed. The method includes soaking the porous substrate in a solution having a first solvent and at least one polymer dissolved in the first solvent at a specific temperature and pressure, such that the solution is deposited within pores of the porous substrate, soaking the porous substrate in a second solvent, such that the first solvent diffuses into the second solvent, and such that the at least one polymer remains within the pores of the porous substrate, and flushing out the second solvent from the porous substrate.

The present invention relates to a watermark formation element for forming watermarks in paper, a cylinder mould cover comprising such a watermark formation element, a method of making such a cylinder mould cover, a method of making paper using such a cylinder mould cover and paper made thereby. The watermark formation element has an integrated body comprising a watermark forming surface, which has one or more watermark forming regions, and a drainage surface. A plurality of drainage channels extend from front surface apertures in the watermark forming surface to the drainage surface. At least some of the front surface apertures are shaped to define at least one of an alphanumeric, a symbol or a pictorial image. A filter layer located between the watermark forming surface and the drainage surface having filter layer apertures which have a maximum width which is less than a smallest width of the front surface apertures.

The present invention relates to a watermark formation element for forming watermarks in paper, a cylinder mould cover comprising such a watermark formation element, a method of making such a cylinder mould cover, a method of making paper using such a cylinder mould cover and paper made thereby. The watermark formation element has an integrated body comprising a watermark forming surface, which has one or more watermark forming regions, and a drainage surface. A plurality of drainage channels extend from front surface apertures in the watermark forming surface to the drainage surface. At least some of the front surface apertures are shaped to define at least one of an alphanumeric, a symbol or a pictorial image. A filter layer located between the watermark forming surface and the drainage surface having filter layer apertures which have a maximum width which is less than a smallest width of the front surface apertures.

The invention relates to improvements in methods of making security features, in particular electrotype security features. The electrotype for forming an image during a paper making process comprises a mesh to which is attached at least one image forming element.

The invention relates to improvements in methods of making security features, in particular electrotype security features. The electrotype for forming an image during a paper making process comprises a mesh to which is attached at least one image forming element.

The present invention relates to non-metallic interference pigments, in particular laminar interference pigments, which comprise a thin high-refractive layer and an outermost layer that contains crystalline carbon in the form of graphite and/or graphene. The invention also relates to a method for producing such pigments and the use of the thus produced pigments.

The present invention relates to electrically conductive, coloured interference pigments, in particular flake-form interference pigments, which have an outermost layer which comprises crystalline carbon in the form of graphite and/or graphene, to a process for the preparation of such pigments, and to the use of the pigments prepared in this way.

A security device (100, 600, 700) includes one or more arrangements of image icons (100a, 110b, 615, 715), one or more arrangements of refractive image icon focusing elements (120, 605, 705), and a sealing layer (127, 600, 1005) which includes an organic resin and nanoparticles. Further, the one or more arrangements of refractive image icon focusing elements is disposed above the one or more arrangements of image icons such that a portion of the one or more arrangements of refractive image icon focusing elements forms a synthetic image of a portion of the one or more arrangements of image icons. Still further, the one or more arrangements of refractive image icon focusing elements contact the sealing layer along a non-planar boundary.

The present invention relates to microparticle compositions comprising an organic IR absorbing pigment having a main absorption maximum in the range from 750 to 1100 nm. The invention also relates to a process for producing said microparticle compositions and to their use in a printing ink, in particular in a printing ink, which is suitable for producing a security feature or a security document. The microparticles of the pigment composition contain the organic IR absorbing pigment as solid particles, which are surrounded by or embedded in an aminoplast polymer, which is a polycondensation product of one or more amino compounds and one or more aldehydes. The microparticle based pigment composition is characterized by a volume based particle size distribution, as determined by static light scattering according to ISO 13320:2009 EN, having a D(4,3) value in the range from 1.0 to 15.0 μm.

The present invention relates to microparticle compositions comprising an organic IR absorbing pigment having a main absorption maximum in the range from 750 to 1100 nm. The invention also relates to a process for producing said microparticle compositions and to their use in a printing ink, in particular in a printing ink, which is suitable for producing a security feature or a security document. The microparticles of the pigment composition contain the organic IR absorbing pigment as solid particles, which are surrounded by or embedded in an aminoplast polymer, which is a polycondensation product of one or more amino compounds and one or more aldehydes. The microparticle based pigment composition is characterized by a volume based particle size distribution, as determined by static light scattering according to ISO 13320:2009 EN, having a D(4,3) value in the range from 1.0 to 15.0 μm.