Tag (image) University of Copenhagen Share Print E-Mail Caption The researchers tested the system by producing tags consisting of QR-codes printed on paper and sprayed with transparent ink containing various microparticles. Credit Thomas Just Sørensen Usage Restrictions The image may be used with appropriate caption or credit. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.