As technological innovation benefits security providers and counterfeiters alike – though luckily not in equal measure – the security industry is under constant pressure to develop a product that is very difficult to counterfeit yet very easy to recognise. Although the general public is accustomed to seeing holograms on, for example, banknotes, the vast majority of people are not sure what to look for in a hologram. More often than not, this uncertainty is attributable to the complexity of the optical design. What is needed is an optical security feature that can be easily verified by the layman while bamboozling the counterfeiter. Enter DID.