The holographic images and text we see on credit cards, paper money, and other important objects have been notoriously hard to reproduce, and were seen as an everlasting security measure, until now. Scientists have discovered a new process using your inkjet printer, and a special ink. The process itself is as easy as sending a document to your ordinary printer.
The method was developed by scientists from ITMO University in Saint Petersburg, and is expected to reduce the cost and time of the current method significantly. The technology has been around since the 1960’s; however, it involves multiple steps.
“The conventional way of preparing a hologram is incredibly time-consuming, and consists of several stages. First of all, one needs to create a master hologram, which is usually laser recorded on a thin layer of photosensitive polymer. The polymer is then dried, and unexposed parts are washed out.
“The resulting stencil is then transferred to a metallic matrix, which eventually serves to emboss holographic micro-relief on the surface of a transparent polymer film,” explains Aleksandr Yakovlev, first author of the study, and a researcher at the SCAMT laboratory.
During the preparation of the master hologram, there are requirements that need to be met, which include temperature control and vibration isolation.
The scientists, led by Alexander Vinogradov, senior research associate at the International Laboratory of Solution Chemistry of Advanced Materials and Technologies (SCAMT) at ITMO University, developed the colorless ink using nano-crystalline titania.
Once loaded into your inkjet printer, and using a special micro-embossed paper, you are able to print out your own holographic images and text. However, you will need to cover it with a clear polymer or varnish.
The key component, ‘nano-crystalline titania,’ gives the ink a high refractive index across the visible spectrum.
“The peculiarity of our ink is high refractive index in all visible range of light,” Vinogradov said. “The use of nano-crystalline ink forms a layer with high refractive index, which helps preserve the rainbow holographic effect after the varnish or a polymer layer is applied on top.”
The new nano-crystalline ink makes it possible to cut the expenditures related to the production of rainbow holograms by several times. The ink is applied with a simple inkjet printer on a micro-embossed surface, which is afterwards covered by varnish. As a result, the holographic image is exclusively seen in those areas where the protective ink was deposited, according to ITMO University.
“Printing separate holographic images in a quick and effective manner is a challenge that, until now, has been unresolved,” adds Yakovlev.
The new technique opens the possibility of obtaining holograms of practically any size, makes the process easier and cheaper, and, for the first time, leads to the creation of unique custom holograms in a matter of minutes, Science Daily wrote.
The real benefit will be for small business, and may have a positive impact on inventory control and quality assurance in the packaging industry. But the question remains — will the inkjet holograms be as secure as their conventional counterparts? The cost of nano-crystalline ink will certainly be higher than regular consumer printing, and let’s face it, standard ink is not cheap.