Skip to Content

Invisible Ink from Xerox

Cartridge works in standard printers.
August 15, 2007

Researchers at Xerox have come up with a way to add fluorescent words and images to documents like checks, coupons, and transcripts using standard printers. The technique makes it possible to create everyday documents that have telltale marks visible only under ultraviolet light.

Now you see it: The words “Row 9 Seat 17 Price” fluoresce thanks to a new printing technique.

Bright white paper is often fluorescent to begin with; the new process exploits that fact by printing the same shades of color in different ways, leaving more or less paper exposed. For example, in standard color printing, which uses cyan, magenta, yellow, and black inks, a gray tone can be produced with lots of the first three and very little black. But it can also be produced with more black and a little color plus the white of the bare paper, which will fluo­resce under ultraviolet light. The same technique can yield a wide range of shades, each produced by multiple combinations of the four ink colors.

The technology boils down to “finding different combinations of the four colors that present the same visual color but provide very different page coverage,” says Reiner ­Eschbach, research fellow at the Xerox Research Center Webster. The necessary software will be incorporated into high-end commercial printers.

Keep Reading

Most Popular

A Roomba recorded a woman on the toilet. How did screenshots end up on Facebook?

Robot vacuum companies say your images are safe, but a sprawling global supply chain for data from our devices creates risk.

A startup says it’s begun releasing particles into the atmosphere, in an effort to tweak the climate

Make Sunsets is already attempting to earn revenue for geoengineering, a move likely to provoke widespread criticism.

10 Breakthrough Technologies 2023

Every year, we pick the 10 technologies that matter the most right now. We look for advances that will have a big impact on our lives and break down why they matter.

These exclusive satellite images show that Saudi Arabia’s sci-fi megacity is well underway

Weirdly, any recent work on The Line doesn’t show up on Google Maps. But we got the images anyway.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.