Working Flat Out

Background: How a security feature is developed

Whatever the sector, it often takes several years to go from initial concept to market launch. At G&D subsidiary Louisenthal, the research and development department needed one year exactly from the original idea to presentation of the RollingStar security thread to banknote specialists. And this despite the developers having to implement a range of features that had never before been combined in a similar product:

Magnetic coding in the security thread ensures banknotes can be processed efficiently by machines

"PL" in cleartext becomes visible when light shines through, enabling positive identification

Requirements for RollingStar:

• RollingStar should have a new, distinctive effect which is easy to distinguish from existing security threads.
• Given the current market trend towards greater dynamism for security features, an amazing degree of motion should be present on the thread.
• It should be compatible with "Cleartext", a kind of reversed-out type in the thread which contains the name of the currency and is easily recognizable for the public.
• The new thread should also be machine-readable. That means it has an invisible, individual magnetic code (e.g. MultiCode) which indicates its authenticity and denomination.
• The optically variable and magnetic properties have to keep their shine and remain resilient whilst in circulation.

The dynamic movement and changing colors

Rolling Bar

Rolling Edge

Extensive trials and test runs were carried out until the RollingStar met these requirements. Here, staff at Louisenthal benefited from the fact that RollingStar combined a new technology with one that was already well established, marrying micromirrors and ColourShift. The interplay between these two technologies ultimately created the distinctive appearance of RollingStar: a dynamic ColourShift reflection.

Further potential for interesting designs

The possibilities of the RollingStar are far from exhausted – indeed, new variants of the design are already in the works. At the Banknote 2011 Conference, G&D merely presented the first two dynamic effects (Rolling Bar and Rolling Edge), which can each be combined with two color changes. Further color shifts are now in the development phases. Central banks can thus adapt the RollingStar to their banknote layouts and incorporate it in their individual designs.