DocuColor Tracking Dot Decoding Guide | Hacker News Reader

DocuColor Tracking Dot Decoding Guide

w2.eff.org

77 pointssr27 comments

How is a printer able to print those dots on so many pages? At some point, this special yellow ink must become depleted, right?

Or does it use the regular ink which is provided by the printer's cartridge? If this is the case, isn't a possible defense to just not buy new color cartridges? At least for me, I have to print colored documents at most every 3 months. Unfortunately the color cartridges dries out after about 6 months which means I would have to pay $20 to print less then 10 pages. Thus, I only buy the black ones and when I have to print something in color, I just put it on a USB stick and print it at work (I am allowed to do that in moderate amounts) or go to a shop with printing services and pay $1 for those documents.

Since my color cartridges are almost two years old (and still full according to my printer), though I cannot print a single page, am I still "affected" by those tracking dots?

The printer uses the yellow supply from your ink or toner. There have been reports of some printers refusing to print monochrome when the yellow is empty, presumably for this reason.

Anecdotally, my yellow always runs out earlier than my C and M cartridges on my home printer, and I mostly print monochrome (these days it's really just character sheets and other stuff for tabletop RPGs that I run)

To add onto this, what about monochrome laser printers? Where is the yellow coming from in those cases?

You should probably just buy a black and white laser printer. They're not much more expensive than inkjets anymore, have excellent Linux support, and you get hundreds of pages per cartridge.

Anecdotally mine occasionally adds garbage to the page, I don't know if this is for tracking or if it's just an artifact of the process, but I haven't really been able to trust a printer for years.

The EFF document "List of Printers Which Do or Do Not Display Tracking Dots" has (update 2017). It mentions it's not necessarily yellow dots and it appears likely that some sort of forensic tracking code is used on all printers.

https://www.eff.org/pages/list-printers-which-do-or-do-not-d...

Thanks you, EFF for giving us useful information about how the government and colluding corporations wish to track us.

I wonder if these are uniformly offset from the printed image, and if so, whether printers incorporate any protection to prevent the user from printing yellow dots near enough to them to mask the signature. (If so, it should be easy to make an extension to add such confounding dots to all printed material…)

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