Digital BW, The Print

I just read an interesting post by Jon Cone here:

http://www.piezography.com/PiezoPress/blog/piezography-technical/making-a-fine-piezography-print/

He says on page 2 of the pdf:

"Because Piezography with four or as many as seven distinct shades of ink can separate more tonal values than can the OEM three shade systems, it is important to start with very smooth image files that have a long tonal scale. Without going into mathematics and the virtues of using overlapping shades of Piezography inks rather than the interlinking shades of the OEM, the Piezography system produces tens of thousands more gray value combinations than can the OEM"

Is this true? When I arbitrarily open up a QTR curve for K7 inks published by Piezography, I find exactly 256 gray values, for each there is an assignment of inks to be used. But 256 (8 bit) gray values, no more no less.

To be provocatine, I say even a single black only (BO) system can print 256 shades gray. To be fair, the multiple ink set-up of K7 (or K3 for that matter) will produce each of the 256 shades with greater smoothness and overall finess than a BO print. Using the 8 bit QTR set-up, both BO and multi K will each produce 256 shades of gray.

I think some people do not realize that if your image is 8 bit, there are 256 shades available, and no interpolation between them is allowed. Even if the ink/paper system is capable of producing more shades than 256, it is never achieved in reality. The same applies even if your image is 16 bits, because QTR curves are described in 8 bit architecture.

In summary, on one single paper, K7, K3, or BO all produce AT MOST 256 shades of gray. It can be argued that using ABW on that same paper, you can actually produce many, many more shades of "near-neutral gray", but only 256 at a time. Again, ABW gets maligned in a manner that has no basis in fact.

Did I get this all wrong? Is there something to this that eludes my mind? Or is the ".........tens of thousands more gray value ....." just poetic waxing?

I concede there are some reasons to chose multi K systems like Piezography K7, but greater number of gray shades?

Shilesh