Watermark– security in the past and today
ARH inside talks
Who would have thought that watermarks – going back all the way to 1282 AD (!) – are still ranked among the best security features in official documents? Let ARH’s product manager Gergely Zámbó explore watermarks through the eyes of a manufacturer of passport reader devices.
So what’s watermark, if you want to explain it in one sentence?
It is a traditional security feature of documents, typically a unique image or pattern, made up of light and dark shades. Similarly to UV marks, watermarks are invisible to the naked eye until a light beam from the right direction makes them visible.
Let’s take a step back – why ‘water’?
During manufacturing, the wet substance is pressed hard, which makes the paper thinner at some points and thicker elsewhere. This is why it lets light pass through differently.
Tell us how this security feature can be verified…
You need to have transmitted light. You can either hold the page against the light, or you can use a purpose-built authentication device. In fact, a recently completed model of our well-known PRMc is actually capable of verifying watermarks – in a single step, together with data reading and other authentication processes.
… and how it can be forged – if that is possible?
When trying to make a counterfeit document, watermarks are usually imitated with a printed pattern – but they are obviously two very different things! While watermarks appear inside the paper, printing is on the surface. Such forgery is easy to spot, as the printed pattern is clearly visible, even if the document is not held against the light. In UV light it again may look very different from other printed elements.
By the way, do many documents include watermark?
We may say watermarks are a compulsory security feature in all paper-based personal documents, like the pages of a passport booklet. Obviously, watermarks are impossible inside polycarbonate IDs; however, the so-called window security features function as modern-day watermarks, in the sense that they are verified via transparent imaging.
OK, so back to the scanner you mentioned. Tell us a bit more.