The precursor to SPARK was OVI®, a colour-shifting ink feature developed by SICPA to prevent the counterfeiting of banknotes by colour copiers.
OVI is produced by coating several thin layers of materials onto a carrier film by vapour deposition. The resulting multi-layer structure produces colour by the physical phenomenon of interference – the core layer is fully reflective just like a mirror, the layers on either side are identical and partially reflective and are separated from the reflective layer by a transparent material. The thickness of the layers determines the wavelength of light that is selectively reflected towards the observer, and hence the perceived colour.
The principle is one of colour pairs, ie. a progressive colour change between two distinctly different colours for a given pigment type as the angle of incidence changes by tilting the note. The deposited film structure is removed from the carrier film and then converted into small pigment particles. These are, in turn, incorporated into a versatile range of ink formulations of specific drying chemistries required for security printing, in particular intaglio and silkscreen printing.
SPARK – the early days
SICPA’s next iteration of OVI came in 2006 with the launch of SPARK technology, created from a colour-shifting ink produced in the same manner as OVI but with the addition of a magnetic layer forming the central reflective layer. The colour-shifting magnetic ink is generically known as OVMI® and the pigments as OVMP®.
The magnetic layer enables the OVMP in the ink to be oriented by strategically placed magnetic assemblies as the ink is silkscreen printed and then immediately UV cured. This uses a module developed by Koenig & Bauer Banknote Solutions for its NotaScreen press. By varying the respective position, shape and strength of the magnets, different dynamic effects are obtained.
SPARK Origin® was the first version of this optical security feature. It was quickly adopted by central banks, with some of its first applications being on the Kazakhstani 5,000 tenge commemorative note and the Chinese 10 yuan Olympic commemorative note, whose rolling-bar effect has to date been the most adopted SPARK Origin dynamic feature.
By 2014, eight years after its release, SPARK Origin was protecting more than 60 denominations in over 40 countries.
In 2014, SICPA introduced the second generation – SPARK Live®. Based on the SPARK technology, it uses finer nickel-free pigments and a modified magnetisation module, which enable a wider range of high-definition effects and design opportunities.
SPARK Live was initially launched with four families of effects, namely:
- Rolling bar – with a bright bar crossing the motif vertically or horizontally.
- Sandune® – which captures the feel of rippling sand.
- Truspin® – with three-dimensional effects around a focal point.
- Openform® – personalised forms, shapes and patterns.
SPARK Live works very well as a stand-alone feature, but it was, and still is, often used in combination with other security features, when its effects of both colour change and movement synchronise with them.
In the 15 or so years following its introduction, SPARK in one form or another has been incorporated into 300+ denominations of both circulating and commemorative banknotes.
And now – SPARK Flow®
Building on this success is the third iteration of the technology – SPARK Flow.
According to SICPA, SPARK Flow marks the beginning of a new level of technological maturity where the feature brightness is increased, dynamic effects are expanded, and highly complex combined effects become industrially viable.
SPARK Flow is powered by a number of technological breakthroughs.
First is SPARK Flow® PRIME. It is the core innovation of SPARK Flow, producing heightened brilliance, colour saturation, contrast and sharpness. The prime attribute is unparalleled visibility obtained through an innovative pigment-orientation process – a biaxial pre-alignment magnetic module.
Second is SPARK Flow® DIMENSION, which exhibits dynamic optical features with an augmented 3D visual impact, adding the dimension of volume to a broad variety of shapes, forms and patterns. This is achieved by a new biaxial simultaneous-alignment magnetic module positioned on top of the magnetic cylinder prior to UV curing, together with the latest customisable magnetic assemblies.
And SICPA has also announced a next promising step, which will be available from 2022 onwards: SPARK Flow® CONFLUENCE. It is created in one single pass through successive magnetisation modules and selective, sequential curing, to generate dynamic optical features with combined effects in contrast, fusion and sequence.
The printing modules for SPARK Flow were co-developed by SICPA and Koenig & Bauer Banknote Solutions, and are implemented by the latter.
SICPA envisages that SPARK Live and SPARK Flow will co-exist in the coming years as central banks and security printers continue to use the technologies to develop high security, unique features.