# Do Printers Leave 'Tracers" to ID you?

**URL:** <https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788>\
**Category:** Factual Questions\
**Created:** [April 12, 2007, 12:33pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788 "2007-04-12T12:33:33Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![RyJae](https://avatars.discourse-cdn.com/v4/letter/r/9d8465/32.png) [@RyJae](https://boards.straightdope.com/u/RyJae)\
**Post date:** [April 12, 2007, 12:33pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788/1 "2007-04-12T12:33:33Z")

</div>

I have heard this in relation to crime solving before, but I cannot find the truth. When you print your documents does the printer leave an identifying mark on the paper? Telling a sleuth your mac address or anything at all?

---

<div class="post-metadata">

**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\
**Post date:** [April 12, 2007, 12:44pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788/2 "2007-04-12T12:44:51Z")

</div>

> [@](#):
>
> 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.
> 
> Peter Crean, a senior research fellow at Xerox, says his company’s laser printers, copiers and multifunction workstations, such as its WorkCentre Pro series, put the “serial number of each machine coded in little yellow dots” in every printout. The millimeter-sized dots appear about every inch on a page, nestled within the printed words and margins.

From here: [http://www.pcworld.com/article/id,118664-page,1/article.html](http://www.pcworld.com/article/id,118664-page,1/article.html)

I also found this bit of info while poking around on google:

To see the yellow tracking dots, use a blue LED flashlight and a magnifying glass. The yellow dots will appear black under the LED.

---

<div class="post-metadata">

**Author:** ![butler1850](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@butler1850](https://boards.straightdope.com/u/butler1850)\
**Post date:** [April 12, 2007, 3:02pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788/3 "2007-04-12T15:02:01Z")

</div>

Interesting. I work on the print servers here at work, and had no idea that the devices encoded information to each printed page. I’m going to have to find a Xerox device around here and check it out!

---

<div class="post-metadata">

**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\
**Post date:** [April 12, 2007, 4:56pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788/4 "2007-04-12T16:56:18Z")

</div>

The Electronic Frontier Foundation has been [working on this](http://www.eff.org/Privacy/printers/) for some years.

[This page](http://www.eff.org/Privacy/printers/docucolor/) shows what the dots look like, and how to decode them (at least for Xerox products)

---

<div class="post-metadata">

**Author:** ![RyJae](https://avatars.discourse-cdn.com/v4/letter/r/9d8465/32.png) [@RyJae](https://boards.straightdope.com/u/RyJae)\
**Post date:** [April 12, 2007, 6:01pm UTC](https://boards.straightdope.com/t/do-printers-leave-tracers-to-id-you/399788/5 "2007-04-12T18:01:52Z")

</div>

Wow it is true, I’m actually shocked more isn’t said about it. Thanks for the information.