NEW!Your Printer Is Giving You Away: How “Yellow Dots” Undermine Your Privacy
Imagine you print a document, put it on your desk, and think: whatever is written on this sheet is all anyone could possibly know about it.
In reality, things look very different. Many modern color laser printers and copiers secretly add metadata to every printout – invisible to you, but readable to forensic experts and government agencies. That’s what the infamous “yellow dots” are all about: tiny yellow points that act like a machine fingerprint on every single page.
This article gives you a complete picture of what these yellow dots are, how they came about, who uses them, how they interact with cloud tracking, and what realistic defense strategies you actually have today.
1. What “Yellow Dots” Are – and Why You Never See Them
Many color laser printers and color copiers print additional information on the page with every job, without you noticing. This information consists of a matrix of tiny yellow dots spread across the entire page. Technically, they’re known as printer tracking dots, Machine Identification Code (MIC), or simply yellow dots.
Each dot is about 0.1 millimeters in size, spaced roughly one millimeter apart, and arranged in a grid, for example 8×16 dots. This grid encodes data such as:
- the printer’s serial number
- the date and time of the print job
To make sure this “signature” isn’t lost, the pattern is repeated across the page, often dozens or even hundreds of times. Analyses show that the same code can appear up to 150 times on a single A4 sheet – even if you shred the paper into strips, enough fragments can remain to reconstruct the code.
In everyday use, all of this is invisible: under normal light the pages look completely ordinary. Only under blue or UV light, or after image processing that boosts the yellow channel, does the pattern become clearly visible. That’s exactly how forensic experts work, and that’s how organizations like the Electronic Frontier Foundation (EFF) were able to analyze these codes in the first place.
2. From Counterfeit Panic to Forensic Infrastructure
The history of yellow dots goes back to the 1980s, when high‑quality color copiers and printers were becoming more affordable. Manufacturers like Xerox and Canon developed mechanisms that would allow the source of a printout to be uniquely identified. Officially, this was to address fears about counterfeiting money. Xerox even obtained a US patent for a system that scatters tiny yellow dots across the printed area to identify the device.
For a long time this remained an internal matter. The technique only became publicly known in 2004, when Dutch authorities used printer codes to track down counterfeiters. Shortly afterward, PC World reported that color printers had been placing such invisible markings on pages for years.
The real breakthrough in understanding came from the EFF. In 2005, they called on users to send in test pages from different color laser printers and began systematically decoding the patterns. It quickly became clear that these yellow dots were not a niche oddity of a few models, but a widespread feature across entire product lines. In a FOIA case, the EFF unearthed internal documents suggesting that all major color laser printer manufacturers had agreed with governments to make their devices forensically traceable.
The issue even reached the political level. In 2007, members of the European Parliament raised questions about whether these hidden tracking mechanisms might violate privacy and human rights protections. The European Commission had to admit that there were no specific laws regulating this technology, and that it clearly raised fundamental rights concerns – especially regarding privacy and the protection of personal data.
In short: yellow dots were not an accident. They are the result of deliberate decisions made between manufacturers and governments, with the explicit goal of being able to link printed documents back to a specific device – even years later.
3. Reality Check: The Reality Winner Case
By 2017 at the latest, the real‑world impact of this became obvious. Former NSA contractor Reality Winner printed a classified report on Russian cyberattacks against the US election system and leaked it to investigative outlet The Intercept.
The newsroom scanned the document and published it as a PDF with almost no changes. Soon after, several readers and security experts noticed that the pages contained clearly visible yellow dots once you enhanced the colors. At the same time, outlets like The Atlantic and Ars Technica reported that EFF tools could reconstruct the exact print time and printer ID from these dots.
Officially, Winner was identified mainly through internal NSA access analysis: only a handful of employees had opened the report, and only one of them had also been in contact with The Intercept. But in the public eye, yellow dots became the symbol of how quickly “anonymous” leaks can be traced once a printer is involved. Even Wikipedia explicitly notes that the way The Intercept published the document – complete with printer markings – likely contributed to identifying the source.
For many in the security community, this was a wake‑up call: it’s not enough to strip metadata from PDFs or use secure channels for digital transmission. As soon as a color laser printer is involved, the paper itself can turn into a forensic trap.
4. Which Printers Are Affected?
For your own everyday practice, the next question is crucial: does this actually affect you? The answer depends heavily on the type of printer you use.
For color laser printers and professional color copiers, the evidence is strongest. Studies and analyses show that virtually all examined devices in this class implement some kind of tracking code – most often as a yellow dot pattern, sometimes in other forms. The classic EFF list only covers a subset of models but clearly states that “it is likely that all recent commercial color laser printers print some kind of forensic tracking code, not necessarily yellow dots.”
The situation is different for black‑and‑white laser printers and inkjet printers. Neither the EFF nor academic surveys have been able to show that these classes systematically embed yellow‑dot signatures with serial number and timestamp. The Wikipedia overview explicitly describes a procedure that in practice is mainly used on color laser printers and photocopiers.
That doesn’t mean B/W lasers or inkjets are automatically “clean” – in theory, manufacturers could introduce subtler watermarks using grayscale patterns or toner density. It just means that the specifically documented yellow‑dot mechanism is a color‑laser problem. If you’re printing at home on an inkjet, you’re in a far more relaxed position in this regard than in a corporate environment with a fleet of fast color MFPs (multifunction printers).
5. How the Technology Works Under the Hood
To understand what you can realistically do about it, it helps to look at the technology. The dot patterns are not generated by your operating system or printer driver. They’re created directly in the device, typically in the firmware or in a dedicated rendering path of the printer controller.
When you send a document to print, the content is rasterized internally first. Then a second, invisible layer consisting of the dot pattern is laid over that raster. This layer is independent of your document’s colors. It doesn’t matter whether you’re printing a colorful flyer or plain black text – the pattern appears anyway.
The pattern itself is a kind of binary matrix. Each position in this grid represents a bit or group of bits that in turn encode part of the information – similar to a 2D barcode. Depending on the manufacturer, serial number, date, and time are stored in different formats, sometimes with checksums and marker bits for orientation. In 2018, researchers at TU Dresden identified four different coding schemes used across 106 models from 18 manufacturers.
The dots become visible when you scan a section of the page at high resolution, isolate the yellow channel, and crank up the contrast. At that point you see a regular grid of dots that looks like a tiny starry sky. This is exactly the visualization method the EFF uses in their guides, and it’s the basis for tools like DEDA that analyze the patterns automatically.
6. DEDA and Other Research Projects: What You Can Do With the Dots
TU Dresden didn’t stop at merely discovering the phenomenon. As part of the “deda” project (tracking Dots Extraction, Decoding and Anonymisation), researchers developed tools to automatically detect, decode, and, to some extent, anonymize tracking dots.
The DEDA toolkit can extract yellow‑dot patterns from high‑resolution scans and, using known encoding schemes, infer the serial number and print time of the device. It also includes functions to compute new dot masks that add extra points when a document is re‑printed. The goal is to disrupt the original pattern so much that it can no longer be reliably attributed to the original printer.
Another important piece of research is Maya Embar’s paper “Printer Watermark Obfuscation,” presented at an ACM conference in 2014. The study tested various strategies for neutralizing color laser printer watermarks. A full firmware hack (“root bypass”) turned out to be extremely risky and hardly feasible in practice. A brute‑force approach of simply covering the entire page in yellow failed because the printer’s internal calibration still kept the dots distinguishable. The most promising method was a steganographic overlay that places an additional dot pattern strategically on top of the original. DEDA’s anonymization features essentially build on that principle.
It’s important to note: these tools do not change the behavior of the printer itself. They work post hoc – on scans or via re‑prints – and they are primarily intended for research, awareness, and legitimate protection in high‑risk scenarios, such as for journalists or activists whose lives may be at risk if their printouts can be traced.
7. Legal and Ethical Gray Areas
The existence of yellow dots raises some uncomfortable fundamental questions. For one thing, they were introduced without transparent user information. Even today, many printer manuals contain no mention that color laser printers silently print hidden identification codes on every page. For another, these codes can be used to identify people who never consented to this and may not even know the mechanism exists.
As early as 2008, the EFF pointed out that tracking dots could potentially violate fundamental rights – especially the right to privacy and family life and the right to data protection as guaranteed by the European Convention on Human Rights and the EU Charter of Fundamental Rights.
At the same time, using these codes is in many cases legally supported or politically desired – for example in fighting counterfeiting or certain forms of organized crime. For you as a user, this creates a troubling tension: on the one hand, you don’t want counterfeit dollars or euros circulating; on the other, you don’t want every printed page to be able to quietly turn you over to authorities.
Things get even more sensitive when it comes to anti‑forensics. Anyone who intentionally tries to neutralize yellow dots may quickly find themselves in legal gray zones, especially where state‑protected classified documents are involved. Tools like DEDA should therefore be approached with care and not be understood as a general recommendation, but as evidence of how deep the problem runs.
8. Why You Can’t Just Turn the Dots Off
From a security‑conscious user’s perspective, the ideal solution sounds trivial: open a menu, uncheck “enable tracking codes,” done. The fact that this option doesn’t exist is not an accident.
The generation of yellow dots takes place at a level that is not meant to be exposed to you. Manufacturers don’t document them as features, they don’t appear in any settings dialog, and there is no interface in the printer driver for controlling them. They’re part of the device’s internal logic, similar to calibration steps – except that here, a deliberate forensic marker is being set.
Research that tried to bypass this logic at the firmware level concluded that while it might be theoretically possible, it is extremely risky in practice: a single mistake while patching can brick the device, and whether such an intervention is legal at all depends heavily on the country, contract terms, and use case.
Realistically, there is no “clean” method to disable yellow dots on a color laser printer. You can only avoid them by using other printing technologies, or you can attempt to blur their effect after the fact – with all the limitations and risks that entails.
9. Avoid Rather Than “Fix”
The most important takeaway for your daily life sounds unspectacular but is highly effective: if you want to prevent yellow dots from appearing on your printouts, don’t print sensitive content on color laser devices.
For confidential documents that truly need to be on paper, prefer black‑and‑white laser printers or inkjet printers. For these device classes, there are currently no publicly documented yellow‑dot implementations, and they are not a focus of known forensic documentation.
Second, ask yourself more generally whether something really needs to be printed at all. Today, many things can be handled more safely in digital form – through end‑to‑end encrypted messengers, encrypted email, zero‑knowledge cloud storage, or dedicated secure document platforms. Every sheet of paper that never exists is one less trace.
And if a color laser is unavoidable – for example in a corporate environment – you should never treat documents printed there as “anonymous.” They are very likely uniquely tied to a device, a network, and often even to a specific group of users.
10. The Second Trail: “Smart Printers” and Aggressive Telemetry
While yellow dots mark the analog end of the metadata chain, a second trend has exploded in recent years: printers that are constantly talking to the cloud.
Manufacturers like HP describe fairly openly in their current privacy statements what kind of data they collect from connected printers. Under labels like “printer usage data,” HP lists, among other things: the number of pages printed, print modes used, paper and media types, ink or toner cartridges in use (including whether they’re original or third‑party), the file type being printed (PDF, JPG, etc.), the application used (e.g., Word, Excel, Photoshop), file sizes, and timestamps.
Other sources describe how users sometimes stumble, almost by accident, on the sheer volume of usage data their devices are sending to vendor servers – especially when using services like Instant Ink, HP Smart, or similar cloud offerings.
Here’s the crucial point: even if you use a printer that doesn’t embed yellow dots, you might still be generating an extremely detailed digital trail. Anyone with access to this telemetry data knows not just that you printed something, but often also when, how much, with which software, and from which device – sometimes even whether you used original toner or not.
11. What You Can Do as a Private User
If you care about privacy, a fairly clear strategy emerges for your personal setup. First, think about what kind of printer you already have or are planning to buy. A simple inkjet or a monochrome laser printer is a better choice than a current color laser when it comes to yellow‑dot tracking.
If you already have a network‑capable printer, it’s worth looking more closely at its associated cloud services. For every “smart” feature, ask: do I really need this? If you don’t regularly print from the cloud or via mobile apps, you don’t necessarily need to register your printer with the manufacturer. Many devices work just fine in LAN‑only mode, for example over IPP or traditional network print sharing, without direct internet access.
A sensible measure is to treat the printer in your home network like a semi‑untrusted IoT device: isolate it in its own VLAN or at least apply strict firewall rules so it can’t freely talk to random servers on the internet. If you notice that certain features don’t work without a cloud backend, you can decide on a case‑by‑case basis whether the convenience is worth the data leakage.
And finally: be mindful with physical paper. Sensitive printouts don’t belong in the recycling bin; they belong in a shredder that really cuts the material into fine pieces. Even aside from yellow dots, this is basic good practice from a classic forensics perspective.
12. What Organizations and Businesses Should Do
In a business context, the issue becomes much larger. We’re talking about entire fleets of multifunction devices, compliance requirements, internal investigations, and questions around how much transparency you owe your employees.
A good first step is a clearly defined printer strategy as part of your IT security and data protection policies. That includes conscious decisions about which printer classes may be used for which types of documents. It may make sense to restrict highly sensitive printouts to dedicated monochrome devices located in particularly secure areas.
The next layer is network architecture. Printers should not be treated as “dumb peripherals” but as standalone IT systems with telemetry, firmware, and potential vulnerabilities. That means segmentation, firewalls, logging, and clear patch management. Cloud features should be disabled by default and only enabled after an explicit risk assessment.
Equally important is employee education. Very few people know that color laser printers embed hidden identification codes. If your organization deals with topics like whistleblowing, internal investigations, or collaboration with journalists, you need to be transparent that physical printouts are not automatically “untraceable.”
Finally, organizations must keep the legal perspective in mind. If you systematically use yellow dots or telemetry data to trace documents back to individuals, you are quickly touching data protection law, works council agreements, and sometimes employment law boundaries. Close coordination between IT security, data protection officers, and legal counsel is essential.
13. Yellow Dots as a Lesson in Hidden Metadata
If you zoom out a bit, yellow dots are above all a lesson in how far hidden metadata goes today.
Photos contain EXIF data with camera model, serial number, and often precise GPS coordinates. Office documents store editors, author names, and revision histories. PDFs retain creation and print timestamps. Messengers and email systems generate highly detailed communication graphs. Printers stamp serial numbers and timestamps invisibly onto paper.
None of this has to send you into panic mode, but it should make you more alert. Privacy in 2025 doesn’t mean clearing cookies once a year and carrying on as usual. It means treating metadata – digital and analog – as a first‑class concern, and asking with every new technology: what extra information is being generated here, and who can analyze it?
This is exactly where projects like DEDA and initiatives like the EFF come in. They don’t just show that the problem exists; they show that as an informed user you’re not completely powerless. You can question technology, you can make conscious choices, and you can apply political pressure to ensure that such mechanisms are at least transparent and regulated.
14. Conclusion: Your Printer Is More Political Than You Think
A device that’s supposed to do nothing more than put text and images on paper is secretly marking every page with a unique signature. An infrastructure that was officially created to combat counterfeiting is now routinely used as a forensic tool – with no opt‑out, no menu setting, and no real public debate.
You can’t simply configure this reality away, but you can incorporate it into your security strategy. You can decide when and where color laser printers are allowed to be used. You can deliberately restrict cloud services and treat devices in your network as what they really are: independent data sources with their own risk profile. And you can ask yourself, for every document, whether it truly needs to exist on paper.
For us at Protectstar, that’s the core of the issue: knowledge, transparency, and tools that help you regain control over your own data – whether it ends up on a smartphone, in the cloud, or on a seemingly harmless sheet of paper.
Sources and Further Reading
- Wikipedia: Printer tracking dots – Overview of technology, history, and use of yellow dots.
https://en.wikipedia.org/wiki/Printer_tracking_dots - EFF: List of Printers Which Do or Do Not Display Tracking Dots – Historical list of tested color laser printers, with the note that most newer devices likely use some form of tracking code.
https://www.eff.org/pages/list-printers-which-do-or-do-not-display-tracking-dots - EFF: Printer Tracking / “Is Your Printer Spying On You?” – Background on the discovery of the codes, FOIA work, and privacy implications.
https://www.eff.org/issues/printers - TU Dresden – DEDA Toolkit – Project page for TU Dresden’s toolkit for extracting, decoding, and anonymizing tracking dots.
https://dfd.inf.tu-dresden.de/ - DEDA GitHub Repository – Technical details and source code of the DEDA toolkit.
https://github.com/dfd-tud/deda - Maya Embar: Printer Watermark Obfuscation, RIIT 2014 (ACM) – Academic work on strategies for disrupting or disabling printer watermarks.
https://dl.acm.org/doi/10.1145/2656434.2656437 - EFF: EU: Printer Tracking Dots May Violate Human Rights – Analysis of the human‑rights dimensions of tracking dots in Europe.
https://www.eff.org/deeplinks/2008/02/eu-printer-tracking-dots-may-violate-human-rights - HP Global Privacy Statement (2024/2025) – Sections on “Printer Usage Data” describing in detail which usage data HP collects from printers.
https://www.hp.com/content/dam/sites/worldwide/privacy/pdf/2025/aug/EN.pdf - Regula Forensics: Printer Tracking Dots: Hidden Security Marks (2025) – Description of how forensic service providers use yellow dots to identify printers.
https://regulaforensics.com/blog/printer-tracking-dots/ - Sophos News: Tool scrubs hidden tracking data from printed documents (2018) – Explanation of how DEDA can be used in practice to detect and partially anonymize tracking dots.
https://news.sophos.com/en-us/2018/07/03/tool-scrubs-hidden-tracking-data-from-printed-documents/ - Ars Technica / The Atlantic on Reality Winner and printer codes – Media coverage of the role yellow dots played in the Reality Winner case.
https://www.theatlantic.com/technology/archive/2017/06/the-mysterious-printer-code-that-could-have-led-the-fbi-to-reality-winner/529350/ - Instructables / EFF: Yellow Dots of Mystery: Is Your Printer Spying on You? – Hands‑on guide showing how to make yellow dots on your own printouts visible.
https://www.instructables.com/Yellow-Dots-of-Mystery-Is-Your-Printer-Spying-on-/
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