Blog - Laser printers' invisible watermark

Technology Laser printers' invisible watermark

20051020printerdots.jpgInteresting find today in the news: a lot of color laser printers and copiers secretly add-in a watermark matrix of microscopic-sized yellow dots. These contain the print date and time, and also the printer's unique serial number. While inoffensive in most situations, this can also certainly be a serious privacy issue.

The scheme, while kept secret by most printer makers, was cracked by the Electronic Frontier Foundation, a non-profit group that fights for digital rights.

Inspecting some color-printed paper at work with a magnifier, I did find some of those yellow dot matrixes.

EFF: Is Your Printer Spying On You?
EFF: List of Printers Which Do or Don't Print Tracking Dots
EFF: DocuColor Tracking Dot Decoding Guide

Posted on October 20, 2005 at 15:56 | Tweet |


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Reminds of the designers name etched onto that replicant snake scale in "BladeRunner".

Personally, I don't see anything wrong with the yellow dots on printers. It's actually a good way to track where something has been printing.

Posted by Roy on October 20, 2005 at 18:26

Yeah, I don't care much either. It's mostly the privacy freaks (and the money counterfeiters) who will go nuts about it.
It's still a surprising thing, you'd think a sheet was white but it's covered with that watermark.

Posted by Patrick on October 21, 2005 at 00:45

If you watched a lot of procedural crime shows (like CSI, which I'm hopelessly addicted to), you would know this. They've used these watermarks in the past to catch baddies!

Posted by Jean on October 21, 2005 at 01:34


Posted by Patrick on October 21, 2005 at 09:56

Though I don't mind much about it, I still think it's a tad freaky. Hence I'm a writer and I sometimes write weird or immoral things and all. Obviously, my papers aren't soon to be checked out by anyone (esp. since I do use a shredder) but nonetheless, I was surprised and a bit shocked (very little) that printer used such watermarks. But in the end, the good use of it will prevail on the abusive one (if any) so...

Posted by Joel on October 31, 2005 at 01:12

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