Next time you make a printout from your color laser printer, shine an LED flashlight beam on it and examine it closely with a magnifying glass. You might be able to see the small, scattered yellow dots printer there that could be used to trace the document back to you.

According to experts, several printer companies quietly encode the serial number and the manufacturing code of their color laser printers and color copiers on every document those machines produce. Governments, including the United States, already use the hidden markings to track counterfeiters.

[...] The dots' minuscule size, covering less than one-thousandth of the page, along with their color combination of yellow on white, makes them invisible to the naked eye, Crean says. One way to determine if your color laser is applying this tracking process is to shine a blue LED light--say, from a keychain laser flashlight--on your page and use a magnifier.

[...] However, they could also be employed to track a document back to any person or business that printed it. Although the technology has existed for a long time, printer companies have not been required to notify customers of the feature.

Lorelei Pagano, a counterfeiting specialist with the U.S. Secret Service, stresses that the government uses the embedded serial numbers only when alerted to a forgery. "The only time any information is gained from these documents is purely in [the case of] a criminal act," she says.

John Morris, a lawyer for The Center for Democracy and Technology, says, "That type of assurance doesn't really assure me at all, unless there's some type of statute." He adds, "At a bare minimum, there needs to be a notice to consumers."