A number of color laser printers leave coded metadata in the form of extremely small, hard to discover, yellow dots.
The dots contain information related to the printers serial number and network connection. They can be used to trace a printed document to its source.
Many people think that if they write a physical letter anonymously to the government, corporations and the police, that they will remain hidden, but in fact the printer is leading them right to you.
Possible ways to detect them:
- A blue LED light
- A powerful magnifier
- A high-resolution scanner
- An image processing program
The dot patterns can also help to restore shredded documents.
Your privacy was lost a long time ago