Paper capable of playing videos has been invented at the Philips Research Laboratory in Eindhoven, the Netherlands. A single sheet looks like ordinary paper. But the ink can be electronically rearranged fast enough to show movies.

The device's creators, Robert Hayes and Johan Feenstra, have also worked out how to create full-colour displays, they report in this week's Nature. Their colour screens would be four times brighter than the flat devices currently made from liquid crystals, they reckon.

The invention is the latest version of "electronic ink". Researchers hope to combine the convenience, robustness and readability of printed material with the vast and flexible information-storage capacity of laptop computers.

In principle, a plastic sheet covered with electronic ink could display an entire library, page by page. The information would be stored in a portable chip, and the display would be powered by a slim, lightweight battery. A large book such as Harry Potter and the Order of the Phoenix would weigh no more than a feather.