Conventional color printing involves overlaying dots of cyan, magenta, yellow, and black pigments in different ratios to get a spectrum of colors. In the new coloring scheme, each pixel is made of four nanopillars topped with metal disks. Nanoscale metal structures, like these disks, act as resonators, meaning that electrons on the metal surface oscillate at certain frequencies depending on the structure’s size. As a result, a metal nanostructure reflects only light of a frequency that matches its oscillating electrons. So by changing the size and the shape of the metal structures, researchers can produce different colors.