[PLUG-TALK] Color laser printers and their microdot codes

Rich Shepard rshepard at appl-ecosys.com
Wed Jun 7 21:19:34 UTC 2017


   This is an interesting article on the use of yellow microdots on pages
printed by color laser printers to record the printer's serial number and,
often, the date and time the page was printed.

<http://www.bbc.com/future/story/20170607-why-printers-add-secret-tracking-dots>

   I use my HP Color LaserJet 2550L (which the EFF documents as printing
these yellow dots) only for color images such as maps and digital photos. I
suppose the dots are much more difficult to see on these pages. For plain
text documents, the HP LaserJet 5 us used to print black text on white
pages.

Rich



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