MrSeb writes: "You’ve heard of laser printers — and now a team of researchers from the University of Cambridge in England have created a laser unprinter that can remove ink without damaging the paper. Despite both methods using lasers, their (un)printing approaches are fundamentally very different. In a laser printer, a laser is used to give individual “pixels” on a piece of paper a positive charge (a separate heat source is used to fuse toner). In the laser unprinter, picosecond pulses of green laser light are used to vaporize the toner, or ablate in scientific terms. The primary goal of unprinting is to cut down on the carbon footprint of the paper and printing industries. Manufacturing paper is incredibly messy business, with a huge carbon footprint. Recycling paper is a good step in the right direction, but it still pales in comparison to unprinting. In a worst-case scenario, The University of Cambridge unprinting method has half the carbon emissions of recycling; best-case, unprinting is almost 20 times as efficient."