Holographie et films
Film appearance
Security holograms can have several aspects since it is possible to use different metalizing materials: aluminium, copper, chrome. Apart from their different appearances these materials have specific resistance properties.
Demetallization
Demetallization is a technology used to create transparent parts in a hologram. These parts are created and integrated at precise positions in the image design and can serve as micro-elements. This technology adds an additional level of security since few companies in the world have mastered the techniques involved.
High Reflective Index (HRI)
HRI is a special metalization technique that leaves the optical image completely transparent and very brilliant. It is used notably in identity document protection systems since it enables both authentication of the document and protection of the variable data covered by the image - but without degrading their legibility. HRI requires special equipment and know-how.
Printing
Microscopic letters or lines can be printed on holograms. Depending on the special inks or vanishes employed the printing may be visible or invisible (in the latter case a special reader is needed, such as a UV lamp or a luminescence reader).