LAS VEGAS—Hey, remember the dress? I know, it was like another century. The dress was white, or maybe it was blue. But next year, thanks to E Ink, it could definitely be both.

We came to E Ink's booth at CES trying to ask about color e-readers and instead ended up fascinated with fashion. Best known for providing the restful, pleasing monochrome displays that grace Kindles, E Ink also makes screens for electronic luggage tags, price tags, business signage, and now, fashion.

The key, in this case, is a new E Ink product called E Ink Prism. It's a plastic film that can shift colors when a current is applied—right now, it shifts between white and one of seven colors. It was designed for "architectural" uses, E Ink chief strategy officer Paul Apen said. But Dai Nippon Printing turned Prism into a dress, which it showed off at a retail tech show earlier this year in Japan.

For now, E Ink Prism's stiffness means that you can't build an entire garment out of it. (It also isn't washable.) It would be perfectly possible to put a color-changing E Ink panel down the side of a skirt, though. In E Ink's booth, we saw a "matador style" jacket that shifted from white to black and back.

As the Prism material is already available, fashion designers could think about working with it now, Apen said. But he said it'll probably take two years or so for the fashion world to figure out how to put shifting E Ink into a garment you'd actually buy.

Where's My Color Kindle?

Whenever I put a Kindle on our One Cool Thing webshow, viewers ask why there aren't any color E Ink e-readers. It's a valid question. When I looked at the huge color E Ink displays with classic artwork hanging on the booth wall, I saw the answer. For now, it takes five to 10 seconds—and a whole bunch of flashes—to change a color E Ink page. That's fine for industrial signage, or for digital picture frames. So that's where you're going to see Color E Ink first. But it won't do when you're reading.

Apen explained that color E Ink uses four different pigments—red, blue, green, and white—and it needs to electrostatically arrange all of them, which means an entire square dance of do-si-dos as the pigments marshal themselves around the screen. E Ink is working on a faster solution, he said, but it sounds like it'll be a few years.