I've known about the yellow dot patterns on color printers for a long time. If you've ever wondered why the yellow ink on your printer goes down faster than you think it should, now you know.
But this article seems to imply that the yellow dots also occur on black-and-white printers. How is that possible?
They give an explicit example of a HP Laserjet. The image is B&W under white light and my experience with Laserjets is that they're B&W printers. I know they make color versions, but that's not how it's presented in the article.
On that page you can see that on the caption of the same image the printer is identified as an "HP Color Laserjet 3700". The BBC journalist or whoever wrote the captions simply wasn't very precise and probably didn't mean to imply that the yellow dots are produced by black-and-white printers.
A lot of printers will just refuse to work without one of the cartridges fitted... Hell, some refuse to print even if one does still have some have ink in it but the printer thinks it should have run out at the time...
Guess an answer would be inject some black or some type of bright ink into the yellow cartridge so the dots show up easily then hole punch those spots out.
The yellow dot codes are repeated across the page and the Wikipedia article on them says there can be about 150 of the codes on an A4 page. Your document would probably look like Swiss cheese by the time you were done with the hole punch!
I did think of this. The whole punch needs to be big enough to obscure the exact location of the dot but not so big all the information trying pass gets lost. My solution was to repeat whatever message or image multiple times on a single page in different locations. That way if the message gets whole punched it shows up in another location so everything is still readable.
That's just the price of avoiding tracking. Do the procedure, create the hole-punched document and complain to the printer manufacturer about the result :)
Well you would need the whole punch big enough that the exact location of a dot would be obscured. Like, every hole would be not perfectly centred over a dot. If it was centred you could essentially establish what the dot location was prior to cutting and give away what you are trying to not do. So what you suggest would show an approximate location of a dot but not reveal the details.
But this article seems to imply that the yellow dots also occur on black-and-white printers. How is that possible?