A Hybrid banknote is basically referred to banknotes printed with part cotton based paper and part polymer. The non paper part comprises of a polymer strip of vertical/horizontal translucent band which usually cover a see-through register and the transparent window either in oval, rectangle or square shape. The band comprises of approx. up to 15% of the total banknote size. Like all security features, the strip was adopted to discourage potential counterfeiter. Initially only two printing firms produced notes with such technology, namely Papierfabrik Louisenthal, a wholly-owned subsidiary of Giesecke & Devrient (G&D) Germany, and De La Rue (DLR) of United Kingdom. DLR's motto is to make life easier for their customers and more difficult for the counterfeiter. The security features printed by G&D and DLR are called "Varifeye" and "Optiks" respectively.
In 2008, Papierfabrik Louisenthal came up with a new generation of new Hybrid banknote printing technique. Instead of the originally polymer strip and a transparent window like those earlier issues, the new Hybrid note comprises of a thin layer of protective film laminated on the paper note. This kind of banknote is intended for use in countries with particularly challenging circulation conditions. Such technology will provide durability on the note without sacrificing the security features and printability. This technology is already in use for the Swaziland 2008 commemorative issues (Celebrating the King's 40th Birthday and Swaziland Independence). The main advantage of such technology is that all the banknote's security features can still be clearly identified even after long circulation, both by the general public and by automatic banknote processing systems.
Until recently, the term Hybrid has been described mainly as paper substrates that combine synthetic with cellulose fibers or paper substrates with an aperture or window which is sealed with a film overlay. With Louisenthal's technology, the inner core of the substrate is a traditional cotton fibre-base construction which is protected with a thin film, laminated to both sides, each around 6 microns thick. The combine weight and thickness of this hybrid note is the same as those conventional paper substrates ie 95 gsm.
It has also reported that Durasafe is developing a slightly difference Hybrid note comprises of a fusion of paper and polymers, with the paper sandwiching the polymer core and is being developed for the new Swiss series of banknotes to be introduced some time in 2010.
Whilst polymer banknotes technology is still proven to be the better option, perhaps Hybrid banknotes are more economical to manufacture but not as cheap as those traditionally cotton based banknotes. The recent release of a Papua New Guinea 100 Kina may have something to do with this. Papua New Guinea fully converted all banknotes to polymer in 2008 and yet they decided to release two commemorative notes on 23 April 2009, one in paper (20 Kina) and the other Hybrid (100 Kina). It looks like Hybrid banknote is getting popular in the expense of polymer.