Recycling paper is much better for the environment than throwing it away. However, the process required to make paper fit for a second or third use actually takes its own significant toll on the planet. Pulping, bleaching and drying recycled paper contributes substantially to energy use, water pollution and climate-damaging gas emissions.

A truly environmentally-friendly solution is needed for recycling our paper. What if we could erase ink – if the documents we no longer needed could simply be ‘unprinted’?

Scientists from Rutgers and Oregon State University have recently shown that we can do just that, using flashes of light from a Xenon lamp. Unlike ultraviolet and infra-red light used in previous studies, the visible light from the lamp didn’t cause any damage to glossy printing paper. They adjusted the length of the light flashes until they found the optimum amount to render printed black ink completely removable with an ethanol wipe. They then studied both new and unprinted paper under the microscope, revealing that the unprinting process restored paper to within 6% of its original brightness.

With upwards of five reprints needed before paper became damaged, this method could rival conventional paper recycling and reduce its environmental impact by about five times. The technology could one day be integrated with conventional printers, making unprinting the new, truly eco-friendly way to recycle paper at home.