I enjoyed reading Marc Riquier’s article, “The History of Plastic Banknotes: It All Started in Belgium!” in Vol. 51:1 about the role Union Chimique Belge played in the development of the Guardian substrate popularized by Securency International. However, I have practical and technical objections to the use of the term “hybrid” to describe notes employing Giesecke & Devrient’s varifeye or De La Rue’s Optiks.
As a practical matter, Hybrid (with a capital H) is G&D’s term for its patented substrate comprised of cotton fibers sandwiched between layers of plastic. To use hybrid (with a lower-case H) in conjunction with different, competing products only invites confusion.
From a technical standpoint, both varifeye and Optiks create see-through windows by applying thin transparent films over apertures in paper substrates (see my articles in Vol. 47:1 and 47:4, respectively). While it’s true that the films are polymers and appear on paper notes, the mere addition of a disparate material to the substrate doesn’t change the classification of the substrate. If it did, any banknote with a security thread, foil patch, or holographic stripe would be a hybrid.
Collectors should adopt the terminology used by the security printing industry, in which the term hybrid is applied only to banknotes with substrates that are a combination of paper and polymer. G&D’s Hybrid substrate certainly qualifies and has already been used on notes such as Swaziland’s 100- and 200-lilangeni commemoratives dated 2008. Landqart’s Durasafe takes the opposite approach, placing paper on the outside and a polymer core at center. The Swiss National Bank is using Durasafe for its new series of notes expected to be issued in 2013.
Owen W. Linzmayer 7962