Secret Tracking Codes Embedded in Printouts

Decrypt thisDo you own or use a color laser printer? If you do, chances are that there is a secret code printed on each page you send out. According to the TG Daily:

For the better part of the last year, computer experts have known about the existence of printer tracking technology. Last November, PC World published the article, Government Uses Color Laser Printer Technology to Track Documents, which discussed the existence of printer tracking dots. Seth Schoen, staff technologist at the EFF, told us that the PC World article spurred EFF to investigate further. Initially Schoen, like PC World, speculated that the dots would only contain the printer’s serial and model number, but now it is confirmed that there is much more information included. “As it turned out, there is also the date and time, which is accurate to the minute. We didn’t expect that,” says Shoen.

A press release from the Electronic Frontier Foundation provides:

Schoen says that these tracking dots are “all over” every page printed from many printer models. The dots are almost invisible, but can be seen by shining a simple blue LED light on the page. The blue light increases the contrast of the yellow dots and causes them to appear black against the paper background. In the case of one particular printer, the Xerox DocuColor, the dots appear as an eight by fifteen grid that is repeated throughout the page.

You can see the dots on color prints from machines made by Xerox, Canon, and other manufacturers (for a list of the printers we investigated so far, see: The dots are yellow, less than one millimeter in diameter, and are typically repeated over each page of a document. In order to see the pattern, you need a blue light, a magnifying glass, or a microscope (for instructions on how to see the dots, see:

I’ve got a printer which I use primarily for high quality and high volume political printing runs. Odds are that many readers of this site have recieved material printed on it, as I lugged the heavy beast to Austin, TX during the Badnarik campaign. Tens of thousands of pages from the printer were also distributed at the LP Convention in Atlanta. One poster I distributed at the convention was covered nationally by an AP Wire here. In this case, a woman was booted out of the Dallas/Fort Worth Airport for passing out anti-war flyers.

It pretty scary that big brother can track the printers of political materials. Imagine the Brits going after the pamphleteers in the years preceding our Revolutionary War. However, in my case, they were not likely to have been able to track the documents I printed, as my printer does not appear on the list of printers known contain the embedded code. I am using a Tektronix Phaser 850DP, which uses thermal wax, as opposed to a laser process. It is my guess that the thermal process makes it more diffficult to hide the code.

Perhaps former U.S. Supreme Court Justice William O. Douglas said it best with: “We are rapidly entering the age of no privacy, where everyone is open to surveillance at all times; where there are no secrets from government. The aggressive breaches of privacy by the Government increase by geometric proportions.”

Update by Stephen VanDyke: Contrast this to the 1765 Stamp Act:

The Stamp Act 1765 was the fourth Stamp Act to be passed by the British Parliament and required all legal documents, permits, commercial contracts, newspapers, pamphlets, and playing cards in the American colonies to carry a tax stamp. The Act was enacted in order to defray the cost of maintaining the military presence protecting the colonies.

It was of course met with great resistance, with many tax collectors being harassed and tarred and feathered. The similarity of requiring a digital stamp nowadays, with the tax built into the cost of the printer, is none too appealing either.

Stephen Gordon

I like tasteful cigars, private property, American whiskey, fast cars, hot women, pre-bailout Jeeps, fine dining, worthwhile literature, low taxes, original music, personal privacy and self-defense rights -- but not necessarily in this order.

  1. Sounds a little cooky to me. I saw this to, but decided against putting it on my own weblog, because it sounds a little too conspiritorial. I don’t know. It’s just wierd. Loving the blog, I linked to it from mine BTW.

  2. AB,

    It’s not okay to simply not know, when the blog give clear directions for confirming the claim. You can test it and know, either way.

    BTW, when does something become “too conspiratorial”? Is it just before, or after, one decides to post an anonymous blog? (We could be neighbors, and I not know it — is it me?)


  3. Allen Hacker,

    LOL. Yeah, It’s funny when someone calls ‘conspiracy’ and you can literally hand them the evidence “hot off the press” so to speak.

    At this point, it’s proven. And while it is a conspiracy (under the strict definition of the word) let’s just call this a fact now shall we?


  4. What about the old Panasonic dot matrix printers? Are they safer to use and less likely to have the tracking dots?

  5. Carol,

    I think you’re ok if it’s not color (and it’s really old).

    The reason this worked is because yellow is so faint that one couldn’t see it very well against the white background. However, a black and white printer would be much more obvious, as you’d see grey dots speckled around.

  6. Why does not Xerox Printers instead print out heart at Valentines Day?
    Printers all look more or less the same and have more or less the same features. I think you could capture major market shares by making those grey boxes more personal. Why doesn’t Xerox talk to consumers and find out what they really want. Make a printer with some human values built in to make it more than just the last link in the consumption chain. A printer that automatically printed special occasion cards on the right date – a sort of ink filled alarm clock of love that could print out heart at days like Valentines Day? To make these ideas meaningful you would need a lot of input from customers.
    Then consumers can send the printed hearts and spread love to Secret Service!