In the future, printers may be able to remove ink from paper, too.

University of Cambridge scientists have determined that as long as you are using the right type of laser, it is possible to remove toner from paper.

“Previous work on the subject has explored the applicability of ultraviolet, visible and infared lasers under nanosecond pulses for toner removal,” the researchers write in an abstract of the study published by the Proceedings of the Royal Society.

They go on to explain that they have expanded on that method and found that “with the right laser, it is possible to remove toner from paper to enable its reuse.”

We were surprised that there has been previous work on this subject.

But, as lead author David Leal-Ayala points out to the BBC, the ability to re-use the same piece of paper time and time again may prove to be a greener way to recycle than our current system.

“You use electricity, water and chemicals, and to be honest when you print something the only reason that you don’t re-use the paper is because there is print on it,” he said.

“The paper is still in good condition and there is no point going through all the heavy industrial process if the paper is still perfectly fine.”

To remove ink from paper the un-printer way, scientists hit the paper with short laser pulses that vaporize the printed images, but don’t damage–or even discolor–the paper.

The tricky part was figuring out what the right length of laser blast should be, and what color laser would work best. (The answer is four billionths of a second, and green).

Unfortunately, you’ll have to wait to get your hands on an un-printer of your own — the scientists are still perfecting their laser length/color formula. But we’re wondering if in the future, shady politicians and paranoid citizens will no longer need a shredder. Maybe they’ll just feed their documents through a printer and hit “unprint.”

Via LA Times