By Kevin Coughlin

Starting this month, signs inside the Bridgewater Macy's will give more than prices. They'll offer a glimpse of the future.

The signs are made of "SmartPaper," an emerging technology striving to transform how people look at laptops, cell phones, books and newspapers.

SmartPaper is another name for electronic paper, or programmable paper. The idea? Low-power, rewriteable displays that look and feel just like good old paper in that they are readable, portable and affordable.

While the Macy's experiment involves only a dozen signs advertising sales in the kids department, industry analysts say it is an important beachhead for a technology that someday may replace clunky computer monitors and TV screens with cheap sheets that fold in your pocket.

The makers of SmartPaper envision cell phones with pull-out screens, power-stingy laptops with super-crisp displays and electronic newspapers that crumple like the real thing - without clogging landfills.

"It's low-cost, it can be reused millions of times, it will save a lot of trees and it's really convenient to work with," said SmartPaper inventor Nicholas Sheridon of Gyricon Media Inc., a spinoff of the Xerox Palo Alto Research Center where laser printing was born.

Macy's has more modest dreams. It hopes SmartPaper - which allows instant price changes, zapped wirelessly from a central computer - will mean more spur-of-the-moment sales and fewer price discrepancies, a problem that bedevils retailers.

Technically speaking, the 11-by-14-inch signs are plastic, not paper. But they flex just like paper. Reflective, they are legible from almost any angle, also like paper. What really makes these sheets special, however, are tiny electronics embedded inside. Laminated circuits apply a trickle of electricity to millions of hair-thin polyethylene balls, each tinted half black and half white.

Depending on the charge, the balls flip black or white to form letters and images. Once flipped, the balls stay that way until further orders are received. There are no power-sucking liquid crystal screens to illuminate, so these signs need just three penlight batteries to operate.

They are programmed by remote-control: Instructions are beamed to a miniature receiver inside each sign's 1-inch base. A transmitter shoots back a message confirming the commands have been carried out. Each sign costs $100.

Delivering digital features in a plain paper wrapper has been a quest for some of the nation's top minds, from the Massachusetts Institute of Technology to Lawrence Livermore National Laboratories and Bell Labs.

Electronic paper still has a ways to go: Reinventing publishing is a giant leap from selling children's shoes. For now, displays like Gyricon's are limited to two colors (pick your pair). Nor is it clear precisely how tomorrow's headlines will be beamed onto flexible pages for the morning commute.

Still, Macy's six-month trial, and recent advances by Gyricon's main rival, E Ink Corp., suggest it is not too soon to start dreaming of the "mystical information handkerchief," a handy display that tucks in your pocket, said Amy Wohl, editor of the computer newsletter "Amy Wohl's Opinions."

"A lot of the pieces of the technology to allow this are dancing tantalizingly right in front of your eyes," Wohl said. "But it's not quite here yet."

E Ink, an MIT spinoff in Cambridge, Mass., applies low voltage to a special ink brimming with millions of microcapsules. Each capsule holds white particles suspended in a dark dye. Depending on the electrical charge, these particles either take center stage, making the capsule look white, or they submerge in the dye, giving a dark tinge.

After a brief foray into e-signs, the company is focusing on the $40 billion market for computer and television displays.

Teaming with IBM, E Ink last month unveiled a laptop-sized display touted as ideal for high-quality graphics. In February, E Ink and Philips, the Dutch consumer electronics giant, launched plans for sharp-contrast, low-power electronic ink displays for handheld computers and e-book readers. The target date is 2003.

Billboards of electronic paper, meanwhile, may flow from a breakthrough at Lucent Technologies Inc.

Working with E Ink last fall, the Murray Hill company devised a cheap way to print plastic transistors, the circuitry that puts the "e" in e-paper. These pliable electronics can be rubber-stamped onto giant rolls, like a printing press, bypassing costly methods for etching and baking silicon transistors.

Gyricon claims its signs won't fade in sunlight; E Ink says it particles are 100 times smaller - and sharper - than Gyricon's. Either way, each camp thinks electronic paper has a bright future.

"Paper has shown itself to be a vastly superior reading medium," said E Ink Chief Executive James Iuliano, whose investors include three U.S. newspaper chains.

"People really like to read things on paper-like material," echoed Robert Sprague, leader of Gyricon. "This enables them to do that. Today it feels like e-plastic. It will feel more and more like paper."

For its part, Macy's just wants to streamline the cumbersome process of printing signs. Pricing details are currently transmitted to each store, laser-printed on site and then mounted by hand.

"We're not looking at this as a labor savings, although that would be great. Our primary focus is signing integrity," said Ben Diss, directory of information systems for Macy's.

Gyricon says its technology enables quick sign changes within a single department - think "Umbrella Sale!" in a thunderstorm - or chain-wide sales teed up via the Internet. Gyricon says the wireless signals are hacker-proof.

If the Bridgewater test pans out, Diss said he might fancy something far bolder: SmartPaper price tags for products.