Novel printing process switches materials from black to transparent

Olivier Martin © Alain Herzog 2022 EPFL - Researchers have developed a new type of printing process that involves removing material rather than depositing it. Their method could be particularly useful for printing banknotes and ID documents, for example. We-ve developed an entirely new printing process, turning Guttenberg's concept on its head,- says Prof. Olivier Martin, head of the Nanophotonics and Metrology Laboratory at EPFL's School of Engineering. Martin proudly displays a representation of EPFL's logo produced using his team's breakthrough method. The letters in the logo are transparent, while their edges are black or aluminum-colored. The researchers- initial goal was to develop a material that absorbs light completely. They created a material composed of three layers - first aluminum, then magnesium fluoride (a dielectric compound) and finally chrome - sitting on a Plexiglas substrate.