Is Your Printer Spying On You?

MIT”s Media Lab has started a website that helps consumers contact the manufacturer of their printer so they can request that “tracking dots” be eliminated from their machines.

The dots hold information about the serial number, make and model of your printer and were placed there at the behest of the Secret Service—supposedly to help locate counterfeiters. Seeing Yellow, a project by MIT’s Media Lab, claims that after contacting the printer manufacturer about how to disable the tracking dots, the Secret Service showed up at one consumer’s door asking questions. Uh, scary.

From Seeing Yellow:

Most color laser printers made and sold today intentionally add invisible information to make it easier to determine where (and when) a particular document was printed. This seems to have been done as part of a secret deal between the United States Secret Service and the individual manufacturers. Some of the manufacturers have mentioned the existence of the tracking information in their documentation, and others haven’t. None of them have explained exactly how it works or what information is conveyed. No law requires printer companies to help track printer users this way, and no law prevents them from stopping this practice or giving customers a solution to avoid being tracked.

This information is most famously known to be coded by patterns of yellow dots that the printers add to the background of all the pages they print. The yellow dots are hard to see with the naked eye, but can be seen under bright blue light or with a microscope. Their arrangement reveals which printer was used to print a particular document, and sometimes also shows when it was printed. Some of the codes have been understood while others are still mysterious, but none of the printer manufacturers has denied that the dots are intended to help track a particular document to a particular printer (or that they can actually be used for this purpose). This is a direct attack on the privacy of the owners and users of printers, and in particular, on their right to free, anonymous speech.

Here’s a list of affected printers as well as more info from the EFF.

Seeing Yellow [via BoingBoing]


Edit Your Comment

  1. winnabago says:

    Probably something that was an great idea at first (by the US mint or someone who has a proper need for something like this) that has branched out to other, more sinister uses. Don’t print your world domination meeting invites in color, or at least use a photocopier as an extra step!

  2. guymandude says:

    @winnabago: “or someone who has a proper need for something like this”.
    NO ONE has a proper need to spy on you.

    “Don’t print your world domination meeting invites in color, or at least use a photocopier as an extra step.”

    So I guess you don’t get it. If they’re doing this what makes you think its the only thing they’re doing?

  3. CaptainConsumer says:

    They used watermarks in the paper and copy machines (not printer) early on in their attempts to catch the BTK Killer. They traced the photocopies he sent to police back to Wichita State University in 1974-5 so they have had and used this capacity for quite a while

  4. rekoil says:

    This goes way beyond ID – most color printers/copiers (and more recent versions of Photoshop) are coded to auto-detect images of currency and do Bad Things when it does.

    I ran into this first hand about ten years ago at a job where I was printing internal “Certificates” to a color copier. The copier interpreted the filigreee border as counterfeit currency, and printed black squares over it for the first few copies, then shut down completely.

    The copier repair guy was called out, who told me that apparently, not only does it “black out” what it thinks is currency, but the algorithm becomes more sensitive each time it gets triggered (to prevent experimentation) and locks up after enough “attempts” requiring an auth code from the manufacturer to unlock. I also had to give the repairman copies of what we were trying to print, and was told that the manufacturer would send them, along with an incident report, to the Secret Service “for their records”.

    I suddenly felt just a little bit less free that day.

  5. enm4r says:

    @rekoil: And you couldn’t say no because?

    I know I’ve scanned money without a problem. I had a class project and needed a high res picture of part of a bill, and my scanner, nor my copy of Photoshop did anything out of the ordinary. If they would have, I would have promptly been on the phone to customer service and escalated until I was able to return for full purchase price for not disclosing that prior to purchase.

    *I have not read either T&S for either of scanner/Photoshop, and if they were able to present evidence that they did disclose in the fine print that I didn’t read, I would have no further argument.

  6. RandomHookup says:

    I don’t think my printer is spying on me, but I have some suspicions about the credenza.

  7. acambras says:

    I hear they also use this technology to track down the sources of ransom letters, etc.

  8. winnabago says:


    They’re probably putting barcodes on the edge of every sheet of paper too! And RFID in your tires, and all pacemakers are going to be made GPS capable, and don’t forget the facial recognition software in every bus and train. We’re all doomed!

    I don’t mean to make a big thing here, but this system of print-id was instituted when consumer grade color printers started being able to reproduce passable currency, around the early 90’s. It makes some sense in that context, but has enormous potential for false positives, as another poster has noted.

    Like many technologies, it’s not the product, but the implementation that is a threat to privacy. No one would ever push for an end to keeping of phone records, but almost all of us would object to things like using them for profiling. Like another poster said, there are legitimate uses for print tracking, such as how they were used to track down BTK.

    Should a printer phone home if it senses currency? That’s a topic for another thread.

  9. Dickdogfood says:

    OMG, I just did a hi-res scan of a seemingly near-blank page that came out of our color printer and MOMMA, I SEE THE DOTS! I SEE THE DOTS!

  10. JohnMc says:

    First point — cut the conspiracy theories. The secret service has two charters — protect members of the executive branch and their original reason for existence, protection of and assurance that the US money supply is kept free of counterfeiting. When color copiers came out 10+ years ago they got the cooperation from the MFRs.

    Point Two — truly this is old news. As I alluded above the yellow dot schema has been around as long as color copiers. You want to foil the dot pattern for work domination? Then print your Pinky and the Brain flyers with a light yellow watermark. That will wash out any chance of finding the dots.

    Point Three — civil liberties are not lost thru technology so much as the mind and intent of the person who intends to use such information. Did the NJ entrant to the Miss American pageant nearly lose her chance due to the pictures. No. She did so by the nefarious mind of someone attempting to gain and an advantage. (And might end up in the pokey since blackmail carries jail time.)

  11. QuantumRiff says:

    In a similar vein, every paper currency in the US, Euro, and many other nations have a peculiar placing of yellow circles in a pattern. They are all the same distance apart, and in the same pattern. They are not used to track the bill, but prevent copying. Ever try to stick a $20 in a color copier and see what happens? Try it with a Euro, same thing.. Most color copiers now don’t refuse to copy, they print out a notice about counterfitting. And for added fun, try scanning a newer US bill, and opening it in Photoshop! Its the same idea behind the printers, lots of small little yellow dots that are hard for our eyes to see..

  12. QuantumRiff says:

    Another informative bit is here: The EFF. They have much more detail, and example pages that you can print out that will make it easier to tell if your model of printer prints these dots..

  13. Thrust says:

    Couple things to know about counterfeit prevention.

    1: as far as I have heard, to date no color printer or photocopier sold through a retail outlet is capable of the microprint used on currency. Special commercial-grade which must be custom ordered CAN do such things, but these are the printers used by cheque-printing companies etc, which are closely monitored.

    2: The specific color of green used in american currency and the various bill colors for canadian cash will not print on a color copier or fax. The exact color code is locked out of the mixer, even if you match it on screen. The difference between THOSE colors and what it will print are almost impossible to see with untrained eyes and no machines.

    3: Real currency isn’t printed, it is stamped (in a sense). You need very special metal plates capable of withstanding high pressure and heat in order to print a good counterfeit (The true plates in a mint are better guarded than GW Bush). Without these your fake bills will not fool banks, only individual suckers.

    in regards to big brother tracking you through your printouts… They may know what printer make/model printed the page, even maybe the store the printer was bought at, but if you don’t register the printer’s serial number (ie warranty card), they can’t track it.

  14. MalichiDemonos says:

    I just tested it… IT WORKS. Theres a code that is repated on the paper i printed out. Its not the same as the one that they noticed but it is all over the paper. The code is 18×13. any ideas?

  15. Brian Gee says:

    This story (or one like it) made the rounds a year or so ago. I happened to be in the market for a color printer at the time. I used the EFF’s list to find a printer that didn’t tag its output and purchased it with cash.

    Now none of my google maps can be traced back to me (except, maybe, by the starting address on the directions ;).


    PS – if you shine a blue LED or light on the printed page, the yellow dots (if present) stand out pretty clearly.

  16. MalichiDemonos says:

    I actually just scanned the page into my computer and inverted the colors. They stand out a lot better if you use at least 1200 dpi.

  17. MalichiDemonos says:

    Thrust: “if you don’t register the printer’s serial number (ie warranty card), they can’t track it.”

    The place you bought the printer all ready is regestered to selling it. If you buy it they can still track it back to you. Unless the company doesnt keep its sales records. In that case your ok to send your Dear Mr. Pres. letter.

  18. buck09 says:

    Looks like the EFF is helping fund terrorism. By printing a list of which printers do and don’t have watermarks, the counterfitters know what printers to buy. For shame!

  19. @guymandude: Exactly my thoughts.

  20. Trick says:

    So if you don’t register your printer, how do they find you? I never give info for the stupid warranties or product registration.

    So how is the SS going to find my printer?

  21. @Trick: If you use a check or a credit card when you bought it.

  22. Thrust says:

    @MalichiDemonos: Everything known to man seems to have a serial number on it, but not all items in a store are recorded in their paperwork with serial numbers included. I worked a computer store for about a year. Laptops and actual computers, more expensive items like the PS2, and some of the very high end monitors were labled in ways that we COULD track serials. Only products we did track were the computers and laptops. Nowadays that same business hasn’t changed that practice, except some expensive OEM are added to the tracking. Unless its a very high end item they just don’t bother with serial numbers. Printers, especially ones under $900, not worth worrying about.

    For them to track a printer without you sending in the card:
    The store must receive a list of serial numbers for the products when they arrive in the store, the product would have to list is serial number on the side of the box, then (depending on the systems used) they would either have to tie in that serial number to a unique barcode for each item OR add a serial number barcode to each box OR manually enter the serial number into the computer at the time of purchase. If you don’t see them scan a second barcode or input a long string into the computer after it’s scanned, they ain’t tracking it.

  23. ancientsociety says:

    It’s not so much that this techonolgy is in existence that worries me but the intent behind it. Sure, the gov’t likes to say that everything like this is “for our own protection” but it’s not like the positive effects of this technology are verifiable.

    Also, they may say this is only for use against counterfieting but how do we know that’s true? Who decides what is the appropriate use for this technology? Certainly not “we the people”, but some powerful gov’t agency that has a lot of power and little oversight. That’s what fuels conspiracy theories and makes citizens less trustful of their gov’t.

  24. homerjay says:

    I sometimes get the feeling my webcam is looking at me.

  25. @homerjay: They’re watching you…. (Scary Face /w Flashlight)

  26. fairweather says:

    @buck09: I so hope that was sarcasm I read.

  27. Jesse in Japan says:

    Um… can’t you just remove the color ink cartridge and print your documents that way?

  28. guymandude says:

    @winnabago: “They’re probably putting barcodes on the edge of every sheet of paper too! And RFID in your tires, and all pacemakers are going to be made GPS capable, and don’t forget the facial recognition software in every bus and train. We’re all doomed!”

    So I guess the NSA reading your emails and listening to your phone calls is fiction eh? Do you need a road map? The english already have facial recognition software and NYC is thinking about it. RFID exists for your dog. People are already talking about RFIDing your kids and the elderly for “safety”. There is an RFID tag in all new passports. How long do you think it will be before RFIDing prisoners and the armed services (dog tags… right?) is a regular occurrence? None of this is in dispute. So laugh while you can monkeyboy.

  29. Grrrrrrr, now with two buns made of bacon. says:

    Like it’s any surprise that the government is spying on you. And what’s easier than doing the spying yourself? Making corporate America do it for you!

    *sits in the corner wearing tinfoil on his head so the Major League Baseball satellite can’t spy on him*

  30. digitalgimpus says:

    No law requires printer companies to help track printer users this way, and no law prevents them from stopping this practice or giving customers a solution to avoid being tracked.

    This isn’t exactly true. For example, there’s no *known* law requiring you to show ID to board an airplane (and that’s been in court (Gilmore v. Gonzalez).

    Secret laws are possible.

  31. RebekahSue says:


    Point Two — truly this is old news.

    yeah, didn’t Grissom point this out in the first season of CSI?

  32. swalve says:

    There is no constitutional right to anonymity.

    Why SHOULDN’T a product that’s capable of causing damage be tracked? We track guns, cars and Chinese toothpaste. Why not printers that can literally print money (and thus devalue every dollar the rest of us have?)?

    The problem with counterfeiting nowadays isn’t that money is being printed that’s perfect. It only needs to be good enough to pass a few transactions. And color laser printers have been capable of doing this for 5-10 years.

  33. says:

    This isn’t about copying/printing currency. It’s about copying/printing counterfeit checks, which also falls under the responsibility of the Secret Service, and which is a big problem.

    While it’s creepy, the intended target (forgery) isn’t a type of free speech :-)

  34. Coyote says:

    What I’m concerned about is that every page I print is using extra yellow ink. And yet the cartridge costs the same and nothing about this is explained to the customer.