Plasmonic printing produces resolutions several times greater than conventional printing methods. In plasmonic printing, colours are formed on the surfaces of tiny metallic particles when light excites their electrons to oscillate. Researchers at the Max Planck Institute for Intelligent Systems in Stuttgart have now shown how the colours of such metallic particles can be altered with hydrogen. The technique could open the way for animating ultra-high-resolution images and for developing extremely sharp displays. At the same time, it provides new approaches for encrypting information and detecting counterfeits.