[Tuna-Fish]

He's right, you are wrong. Modern color printers sold to consumers run image recognition on the images they print and refuse to print ones that contain features found in real money. Try it if you don't believe me.

They also add watermarks -- small almost imperceptible yellow dots that uniquely identify the printer in question.

[ChikkaChiChi]

I said that in the other comment above you. I knew about the yellow dots, but this is straight up creepytown.