Watermarks for Less Waste

Digital watermark specialist Digimarc was recently featured in a news clip from the BBC, the UK’s broadcaster, on how invisible watermarks could increase plastic recycling.

The clip explored industry testing efforts in Europe and discussed packaging attributes that could be identified through the use of Digimarc’s technology, giving plastic packaging a so-called ‘voice’.

Dr Ravi Sharma of Digimarc explained: ‘today’s technology is able to identify the type of plastic but not necessarily whether it came from a food application or a non-food application. With watermarks, you can precisely identify what it was. Once we can reliably identify the type of plastic, that same type of object or plastic can be reused’.

The watermarks are in the form of invisible unique barcodes that are about the size of a postage stamp and that are repeated across the entire surface of the packaging to create a tile effect that is easy to detect and scan. The codes are either integrated within the packaging label artwork (by means of subtle changes made to the artwork pixels) or embossed into the mould that forms the plastic container.

© PRNewsfoto/Digimarc Corporation.

The codes can carry a wide range of information on the manufacturer, stock-keeping unit (SKU), type and composition of plastic used, and whether food or non-food was contained in the packaging.

The watermarks are a key part of a huge initiative called HolyGrail 2.0, which is driven by the European Brands Association and backed by dozens of global brands, including Procter & Gamble, PepsiCo and Unilever.

The testing efforts have reached the stage of a semi-industrial trial which started in September 2021 in Copenhagen, Denmark, using a prototype detection sorting unit produced by Pellenc ST in collaboration with Digimarc. The prototype is the first of its kind to combine near-infrared/visible detection and digital watermarks in an optical sorting solution and is based on Pellenc ST’s commercial Mistral+ Connect Optical sorter, with an add-on module for detecting digital watermarks.

A high-resolution camera on the sorting line detects and decodes the watermarks, which allows the packaging to be sorted into different streams (eg. food-grade plastics versus non-food-grade plastics). This results in better and more accurate sorting streams and consequently higher quality recyclable material. In the latest tests, sorting accuracy rates of more than 95% were achieved, according to BBC News.

125,000 pieces of packaging representing up to 260 different SKUs were included in the trial, all prepared by HolyGrail 2.0 members.

When asked whether any challenges had been encountered with integrating digital watermarking into its existing systems, Eric Westerhoff of Pellenc ST told Packaging Europe that the three key components of the system were very challenging (ie. high-power LED lighting, multiple high-resolution cameras, and huge computing power), compared with any of its previous technologies.

Regarding the future of the project, Westerhoff advised that its economic feasibility would need to be proven soon, because resources in the recycling industry were not infinite. He said data management with a very rich encoding capability might be difficult, and the types of licences between all actors of the value chain would have to be clearly agreed on.

If successful, digitally watermarked products could be introduced to store shelves, in Denmark, France, and Germany, as early as the first half of 2022, for in-market demonstrations and industrial-scale trials.

This is interesting news for those involved in product authentication, given that, in addition to creating a ‘digital recycling passport’ for packaged goods, digital watermarks can be used in other areas such as consumer engagement, supply chain visibility and brand protection.