Color laser
printers output a serial number indicator of some sort by
a near-invisible pattern of yellow pixels overlaying the printed
image. I imagine it's not 100% reliable but apparently it's been in
place for some time.
It sounds like tin-foil-hat black-helicopter
stuff, but I found
multiple stories about it online in places like The Standard.
If I caught my printer doing that, I would tell them to fix it. If
they tried to claim it was a feature, or otherwise refused, I'd return
it and find a printer that printed what - and nothing but what - it was
given to print.
Sadly I'm not sure you're going to be able to find a good current
colour printer that doesn't do it :^(
Zane
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| Zane H. Healy | UNIX Systems Administrator |
| healyzh(a)aracnet.com (primary) | OpenVMS Enthusiast |
| | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
|