A method for producing a document blank or a security document includes providing a substrate layer having a metal layer or applying a metal layer to a substrate layer, forming a color-effective pattern in or on the metal layer, in which the pattern has a pixel structure and each pixel includes at least two subpixels which cause a monochromatic color effect, and joining together the substrate layer and at least one further transparent substrate layer to form a document body. A security document blank, a personalized security document and a method for the laser personalization of security document blanks in color are also provided.

The invention relates to anisotropic, reflective, magnetic flakes. In a liquid carrier and under influence of an external magnetic field, the flakes attract to one another side-by-side and form ribbons which provide higher reflectivity to a coating and may be used as a security feature for authentication of an object.

There is described a printed security feature (1) provided onto a printable substrate, which security feature includes a printed area (100) consisting of a multiplicity of adjacent rectilinear and/or curvilinear elements (110, 120) printed with a given spatial frequency. The rectilinear and/or curvilinear elements are printed with at least first and second inks which exhibit the same or substantially the same optical appearance when illuminated with visible white light, such that the security feature produces a first graphical representation when illuminated with visible white light, at least the first ink being an ink which responds to non-visible light excitation by producing a characteristic optical response differentiating the first ink from the second ink. The security feature produces a second graphical representation when illuminated with non-visible light, which second graphical representation exhibits a distinctive two-dimensional graphic element (B) which is revealed only when the security feature is illuminated with non-visible light. Inside boundaries (160) of the distinctive two-dimensional graphic element, a part (P3) of the rectilinear and/or curvilinear elements is printed with a combination of the first and second inks, the rectilinear and/or curvilinear elements being subdivided, within that part, into first and second juxtaposed sections (110a, 110b, 120a, 120b) which are respectively printed with the first ink and with the second ink. Outside the boundaries of the distinctive two-dimensional graphic element, portions (P1, P2) of the rectilinear and/or curvilinear elements are printed with only one of the at least first and second inks. The at least first and second inks are printed in register one with respect to the other so that the boundaries of the distinctive two-dimensional graphic element are not visible when the security feature is illuminated with visible white light and the distinctive two-dimensional graphic element only becomes visible when the security feature is illuminated with non-visible light.

A method for marking an item including a shape memory polymer (SMP) having a visual readable and/or machine readable graphic element on the surface of the item. The method includes pretreating the surface of the item; coloring the surface of the item with a dye solution containing an organic dye and an organic solvent; cleaning and drying the surface of the item; and engraving by at least partially ablating the surface of the item. The dyeing process is suitable for coloring the surface of a shape memory polymer (SMP), wherein the information is engraved in a form of a code or other label on the colored surface. The coloring causes an increased contrast and thus facilitates machine readability of marking and coding without affecting the other properties of the SMP.

The invention relates to anisotropic, reflective, magnetic flakes. In a liquid carrier and under influence of an external magnetic field, the flakes attract to one another side-by-side and form ribbons which provide higher reflectivity to a coating and may be used as a security feature for authentication of an object.

A diffraction grating recording medium (3) that enhances the ability to prevent forgery and make security more reliable. The diffraction grating recording medium (3) comprises a first recording region (31) including viewing image unit cells (11a), (12a), (13a) having a light diffraction structure, and a second recording region (32) including hidden image unit cells (2a). The viewing image unit cells of the first recording region (31) has a grating pitch more than the wavelength of visible light, and the hidden image unit cells of the second recording region (32) has a grating pitch less than the wavelength of visible light.