Now You See It, Now You Don't: Xerox Scientists Develop Fluorescent Writing To Deter Counterfeiting

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Cautious merchants know that authentic U.S. currency in denominations larger than $10 has an embedded strip that glows when they hold it under an ultraviolet light. Bills lacking the thread can be identified - and rejected - as counterfeit money. Now scientists at Xerox have developed a technology that makes it easy to add fluorescent writing to protect other valuable documents such as checks, tickets, coupons and certificates.

The new technology builds on Xerox's expertise in color printing systems and how the paper, toner - or "dry ink" - and printers work with human perception to create an image. Recently Xerox scientists have been using that know-how to manipulate images in order to add security features to documents as a deterrent to counterfeiting.

"What amazes people about the new technology is that we can create fluorescent writing on a digital printer without using fluorescent ink," said Reiner Eschbach, a Research Fellow in the Xerox Innovation Group and with Principal Color Scientist Raja Bala, the co-inventor of the patented process. "That means a four-color digital printer can print everything it normally would, and it can simultaneously individualize a document with a fluorescent identifier."

The Xerox technology results from a Eureka moment of inspiration. Eschbach's group had been involved in the creation of Xerox's other specialty imaging technologies such as GlossMark® imaging, which uses the differential gloss in toner to print a hologram-like image, and he wondered if there were a way to make fluorescent marks with conventional toner.

They realized that paper manufacturers put fluorescent brightening agents in paper to make it appear "white." Why not take advantage of the fluorescence that already existed in the paper to solve the problem? Eschbach and Bala discovered certain combinations of toner that would selectively allow the paper's fluorescence to shine through when exposed to ultraviolet light. Based on this insight, Xerox developed a font that uses the contrast to "write" fluorescent letters and numbers.

"Just as the U.S. $10 bill has a fluorescent thread to authenticate it, I can imagine a time when your checks will have your signature printed in a fluorescent stripe," Eschbach said. "A merchant could easily compare the fluorescent signature with the actual one to validate the check."

The new patented technology belongs to a portfolio of technologies that Xerox is developing that build security into documents based on a digital printer's ability to make any element on the page - lines, text, images - unique to the recipient.

The fluorescent printing is one of several specialty imaging technologies Xerox scientists have developed making it easier for a suspicious recipient to tell which checks, certificates, or other printed materials are authentic. The new specialty font is part of the Xerox FreeFlow® Variable Information Suite 5.0, software that Xerox sells to commercial printers that produce personalized documents.