Silver News

Japanese Researchers Produce Film that Changes Color - Reusable Color Paper for Photocopiers Possible

Researchers at the University of Tokyo have developed a film whose color changes when it is exposed to different types and colors of light. The researchers say that paper covered with the film can be used as reusable color photocopier paper.

A solution, which includes titanium oxide particles and silver ions, is applied to a glass substrate which turns the film brown. When exposed to a blue laser, the glass turns blue; when exposed to a white laser, it turns white. The color depends not only the kind and color of laser used, but the size and shape of the silver ions.

The team, led by Tetsu Tatsuma, associate professor at the university’s Institute of Industrial Science, said that when information is written on the film, it lasts for at least a week. The film returns to brown when exposed to ultraviolet light.

Silver News - First Quarter 2003