List of Printers Which Do or Do Not Display Tracking Dots

Time to start printing full yellow background instead of white. Con: lots of yellow toner needed. Pro: no tracking.

Or maybe never refill Yellow toner and then dots fail to appear.

..or a return to dot matrix printers? Good thing I never threw those away.

I think that might make you easier to track. Even driving slowly round the neighbourhood listening carefully would ferret you out.

LOL I'm still not throwing them out. Nostalgia. They'll sit on a shelf next to my Nintendo and typewriters.

maybe this is why some color printers will refuse to print black and white if they're out of the color ink.

Maybe printers don't just use yellow, but calculate an optimal color based on the background of where they need to print.

The person who wrote the list in the article mentions (at https://news.ycombinator.com/item?id=14502425, in this thread) that there is a second generation of this technology that doesn't produce microscopically-visible dots.

Perhaps the use of all available colors is involved.

A daisy wheel printer would actually be less susceptible because a dot matrix could add small dots to the text.

Old manual typewriters were also uniquely identifiable just by virtue of being shitty.

The Lives of Others

There is the latent question of how this works with B&W printers which are still frequently found in offices. I assume that all of these have a similar technique, just sans the colour. I did notice some scattered black dots on a Kyocera printout (FS1000 or so), but with an older laser printer it's hard to tell whether these were actually made by the printing engine, or just spilt toner trickled down by vibrations. These were rather obvious.

However, I - and evidently many others in this thread - can think of many B&W ways to hide data in a printout.

By the way, if someone wants to take a stab at an older printer's firmware — many Kyocera printers from the late 90s and early 2000s used some small PowerPC with the firmware on a mask ROM on a SIMM-like module. Doubtful that there is anything protected there.