Micro formed holographic security features in steel Eckart Uhlmann, Stephanie Schulze, née Frenzel, Julian Polte, Christoph Hein, Johannes Matthiesen and Manfred Böge MATEC Web Conf., 190 (2018) 10002 Published online: 18 September 2018 DOI: 10.1051/matecconf/201819010002