ColorShift™/ColorFix
Louisenthal (Germany)
Type: Colour-shift security thread — dual-zone variant combining tilt-activated colour change with a fixed-colour reference area in a single thread
Overview
ColorShift™/ColorFix is a compound security thread variant developed by Papierfabrik Louisenthal GmbH, the specialist banknote paper and security features manufacturer headquartered in Gmund, Bavaria, Germany, and a subsidiary of Giesecke+Devrient. It builds directly on Louisenthal's established ColorShift™ thread platform — itself introduced in 2007 — by adding a structurally distinct fixed-colour reference zone (ColorFix) alongside the standard colour-shifting zone within the same thread body. The combination was launched alongside the base ColorShift™ product in 2007 and is described on Louisenthal's product pages as ColorShift™/ColorFix to reflect its dual-zone nature.
Technology & Effects
The fundamental principle of all ColorShift™ threads is thin-film interference: a precision-engineered multilayer optical film coating on the polyester thread substrate selectively reflects different wavelengths depending on the angle of incident light, producing a vivid colour change as the banknote is tilted. This is the same thin-film technology used in high-security optically variable inks (OVIs) but applied to a thread format embedded in the banknote paper.
ColorShift™/ColorFix extends this by introducing two structurally distinct zones running along the thread:
While the ColorShift™ surface clearly changes colour when tilted, neighbouring ColorFix areas remain fixed with the same colour. On viewing a banknote, the user can easily distinguish the unchanged reference colour and the colour-shifting area, which typically includes the reference colour in its design.
This dual-zone architecture creates an immediate and unambiguous authentication experience. The fixed ColorFix area provides an absolute colour reference that the observer holds in view simultaneously with the shifting area — so rather than trying to remember what colour a thread "should" be, the observer simply checks that one zone shifts relative to the other. The colour seen in the ColorFix area at normal incidence is typically also visible in the ColorShift™ zone at a specific tilt angle, creating a visual connection between the two areas that is part of the security design.
Unlike standard ColorShift™ threads, the two areas of the ColorShift™/ColorFix thread make it possible to use customer-specific designs. The dual-area concept supports highly attractive designs and eases the authentication of the security feature.
Both zones can incorporate fully transparent demetallised clear text — denomination numerals, central bank initials — which appears as see-through lettering when the thread is viewed in transmitted light, adding a further authentication layer without requiring any tools beyond holding the note to a light source.
Form Factors & Application
ColorShift™/ColorFix is embedded as a windowed security thread in banknote paper during manufacture at Louisenthal's paper mills. It is available in a range of widths and colour combinations, with the colour palette for both the shifting and fixed zones selectable to match the banknote's overall print design scheme. The thread can incorporate proven machine-readable properties — magnetic coatings, conductivity, UV fluorescence — enabling it to function at Level 2 as well as Level 1 within the same physical thread.
Security Levels
The feature operates at Level 1 (public). The simultaneous visibility of the colour-fixed reference and the colour-shifting zone in a single thread makes authentication faster and more reliable than a single-zone colour-shift thread, since the reference comparison is inherent in the feature itself rather than requiring the user to recall a target colour. The demetallised clear text adds a further Level 1 check in transmitted light. Machine-readable options extend coverage to Level 2.
Notable Deployments
Louisenthal does not publish named central bank deployments by individual thread product. The company's security thread reference projects listed on its website include banknotes for Hong Kong, Zambia, Lebanon, and the UAE — though specific thread type assignments per project are not disclosed publicly. Given that ColorShift™/ColorFix was launched in 2007 and is described as being in use on banknotes around the globe, it is among the more established colour-shift thread technologies in global circulation.
- Name
- ColorShift™/ColorFix
- Category
- Security Feature
- Effect Types
- Colour shift
- Company
- Product Page
- View on Supplier Site
- Linked Features
- 1 security feature