The Secret Tracking Dots in Your Printer
Have you ever tried to print a black and white document, only for your printer to refuse because the yellow ink cartridge was empty? While it’s easy to blame corporate greed—since printers are often sold at a loss and companies profit from ink—the real reason is far more interesting and concerning.
Modern color laser printers refuse to work without yellow ink because they are tracking every single page you print with nearly imperceptible yellow dots.
This isn’t a conspiracy theory. In 2004, a senior research fellow at Xerox, Peter Crean, revealed that since the 1980s, major printer manufacturers had a secret agreement with the U.S. government. They agreed to embed microscopic yellow tracking dots on every page printed. These dots form a code that contains the serial number of the printer and the date and time the document was printed.
This system, known as the Machine Identification Code, was initially claimed to be an anti-counterfeiting measure. However, with modern currency security features like 3D ribbons and watermarks, faking money with a standard laser printer is virtually impossible. Yet, the tracking continues.
According to the Electronic Frontier Foundation (EFF), which confirmed the program through Freedom of Information Act requests in 2015 and 2017, it is “likely that all recent commercial color laser printers print some kind of forensic tracking codes.” Their research confirmed that nearly every major brand participates in this practice.
From Physical Print to Digital Light
While printer tracking dots have been known for decades, the ability to embed hidden tracking technology is now making a leap from the physical world to the digital one in a way that is simultaneously genius and terrifying.
In July 2025, researchers at Cornell University published a paper titled “Noise-Coded Illumination for Forensic and Photometric Video Analysis.” They detailed a method for what is essentially watermarking light itself.
This technology allows modified light sources—from computer screens and flashlights to everyday commercial lamps—to emit a coded, invisible fluctuation. Any video recorded in the presence of this light will have this code embedded within it, serving as a baseline validator for the footage.
Genius Authentication or Terrifying Surveillance?
This new technology presents a classic dilemma, offering incredible benefits for security while posing significant risks to privacy.
The Case for Video Authentication
The most immediate and valuable use for watermarking light is combating falsified videos. In an age where AI-generated deepfakes can convincingly fabricate audio-visual material, this method provides a powerful tool for validation.
For example, if a politician’s speech is filmed under these modified lights, any AI-fabricated version of that speech would lack the coded light fluctuations. This would make it easy to identify the forgery. Coding authenticity directly into the light source is a brilliant way to fight misinformation when our ability to create fakes is outpacing our ability to detect them.
The Terrifying Implications for Privacy
Just as printer tracking expanded beyond its anti-counterfeiting mission, the ability to watermark light has frightening implications. Imagine you host a party and someone records a video of an illegal act taking place in your home.
Now, imagine the lamps in your house are broadcasting a unique serial number directly into any video filmed there. If the lamp’s manufacturer or retailer has a record of the credit card used to purchase it, law enforcement could potentially trace that video directly back to you, the homeowner. The literal light in your home becomes another piece of metadata for surveillance.
A History of “Scope Creep”: The Reality Winner Case
To understand how a technology’s purpose can expand, look at the case of Reality Leigh Winner. In 2017, she leaked a classified NSA document to The Intercept by printing it and mailing it to them.
It is widely believed that when The Intercept provided the NSA with scans of the document to verify its contents, the forensic tracking dots on the pages helped the agency identify Winner’s printer and, subsequently, her as the leaker. A 40-year-old technology intended to stop currency counterfeiters was used to identify a whistleblower.
This case serves as a powerful example of “scope creep,” where surveillance tools are inevitably used for purposes far beyond their original justification. What will governments do with the ability to embed information in light itself?
The Unstoppable Trend of Digital Surveillance
Video evidence used to be the ultimate truth. Today, we are shifting to a world where the baseline assumption is that everything is fake unless it can be proven real. This mindset makes video authentication technology extremely valuable.
However, it also feeds into a false dichotomy often presented by governing systems: you can have liberty or safety, but not both. As regulators push for more digital ID checks and online tracking in the name of “safety,” the trend toward more data collection and surveillance becomes clear.
While having mechanisms for validation is essential in an era of rampant AI generation, we must question the long-term cost. The trend points in one direction: eventually, everything, everywhere, will be tracked.
