[Printers] Purdue printer research

[Seth David Schoen]

Why we can't be sure that inkjet or black-and-white printers aren't
printing tracking information:

http://shay.ecn.purdue.edu/~prints/

These researchers at Purdue have developed both passive and active
watermarking techniques for black-and-white printers with the explicit
goal of allowing documents to be tracked back to the individual printer
that produced them.  Unlike the yellow tracking dots, these variations
in intensity ("banding") can't be seen easily using any technique I know
of.

-- 
Seth Schoen
Staff Technologist                                schoen at eff.org
Electronic Frontier Foundation                    http://www.eff.org/
454 Shotwell Street, San Francisco, CA  94110     1 415 436 9333 x107