No ink required: paper can be printed with light

In an effort to curb the adverse environmental impacts of paper production, researchers in a new study have developed a light-printable paper—paper that can be printed with UV light, erased by heating to 120 °C (250 °F), and rewritten more than 80 times. The secret to printing with light lies in the color-changing chemistry of nanoparticles, a thin coating of which can be easily applied to conventional paper to transform it into the light-printable version.

https://phys.org/news/2017-02-ink-re...paper.html#jCp