Rewritable paper goes technicolor. Metal-ligand complexes display a range of long-lasting colors that can be erased on demand, allowing paper to be reused. The paper industry has a significant environmental impact, from cutting down trees for raw material to consuming large amounts of energy and water to process that material. To curb that impact, chemists have been working on rewritable paper technologies that would allow people to print on a sheet of paper with special inks and then erase them to reuse the paper. A team now reports a form of rewritable paper that can display multicolored images and text for months, before being erased and reused time after time. A team at Nanjing University of Posts & Telecommunications overcame these hurdles, using water-based inks and inexpensive materials to form colored metal-ligand complexes that remain stable for at least 6 months. “It is exciting to see that by simply varying the metal ions, a number of distinct colors can be obtained, and the color intensity remains stable for months,” says Yadong Yin at the University of California, Riverside, who also works on rewritable paper and was not involved in this research.