Security element for banknotes or documents with intrinsic value
A security element, comprising at least two contiguous areas having an identical or different coloring which can vary depending on the inclination of the incidence and, therefore, reflection of direct light or depending on the type of incident light. The security element also has a single graphic marking which crosses with continuity the two areas having variable coloring so that the graphic marking straddles the two areas so that it is perfectly aligned, without having discontinuities of any kind. Moreover, the effect of this graphic marking is perfectly visible both when the security element is viewed from the recto and when it is viewed from the verso.
1. A security element, comprising:
at least one supporting element, on which there are at least two contiguous elements which arranged side by side, so that at least one contact region is formed between them, each one of said at least two contiguous elements having a color which can vary depending on how much light they absorb and reflect and on the inclination with which light strikes them, and
at least one graphic marking provided on said security element, at least one part of said at least one graphic marking being provided at said region of contact between said contiguous elements,
said at least one graphic marking being arranged so as to pass through said contiguous elements, crossing said region of contact between said contiguous elements and extending into said at least two contiguous elements with perfect continuity, and wherein the graphic marking when viewed from the recto in transmitted light is mirror-symmetrical to the graphic marking when viewed from the verso in transmitted light, said contiguous elements being provided by inks;
said at least two contiguous elements being slightly overlapped.
2. A security element according to claim 1 , wherein said at least two contiguous elements have different light reflection properties in the visible-light range (wavelength 400-800 nm), in the ultraviolet range (wavelength 254-370 nm) and in the infrared range (wavelength >820 nm).
3. A method for manufacturing a security element, comprising the steps of:
providing a substrate film;
obtaining, on said substrate, two contiguous, laterally adjacent bands or regions, which have a coloring which shifts depending on the light that strikes them, said bands or regions being provided by inks;
depositing on both contiguous bands or regions a material which acts as resist, taking care to leave a region without resist which forms a chosen graphic marking and affects both contiguous regions, said graphic marking having at least one part which affects both contiguous bands or regions and crossing a region of contact between said contiguous elements and extending into at least two said contiguous bands or areas;
immersing the film thus obtained in a series of tanks, which contain acid or basic solutions depending on the materials used, in order to dissolve and remove the parts not covered by the resist, providing the intended graphic marking, wherein said two contiguous regions are slightly overlapped.