to whom it may concern
This is an interesting topic of conversation. For those (like me) who are interested, there are plenty of examples where a brand name becomes generic as has been suggested here. eg hoover (or for Europeans, lux) as a verb meaning to vacuum, Xerox for copy, even Google for search perhaps.
So it is possible that Piezography might mean black and white printing with several tones of black ink.
Apparently there is even a word for it: Genericide.
see also;
http://ndrichardson.com/blog/2012/09/11/brand-genericide-when-brand-names-become-commonplace/
http://www.huffingtonpost.ca/2014/08/22/brand-names-generic-words_n_5699474.html
Cheers
Mike V