Digital BW, The Print

I must be nuts for continuing this, clearly it's going nowhere. I'm going to describe this and you can make of it what you 
want.
I have a particular 16 bit Photoshop grayscale tiff, it has 32,076 levels.
...Slight divergence...
--- In DigitalBlackandWhiteThePrint@y..., "Austin Franklin" <darkroom@i...> wrote:
snip
> > Note that any 16-bit image saved out of Photoshop will have, at a
> > maximum, 32769 unique levels per channel, not 65536 as one might
> > expect...
> This is simply silly.
I suggest you bring that up with Adobe.

> If this is the case, then simply save it as TIFF, and
> you should have no loss problems.
Wrong, not if a Photoshop TIFF, same problem.

> Anyway, even if this does happen, it is
> irrelevant to this discussion.  A 16 bit grayscale file has the ability to
> have 64k possible values per pixel, period.  If Photoshop clips the file to
> 15 bits, then it isn't a 16 bit file.
I assume that would be technically correct.
 
> It also appears that Bruce is talking about RGB files.
Wrong

To continue-
I convert my high bit gray file to a high bit CMYK file per Dan Culbertson's method. This gives me a four channel high bit file 
with each channel nearly identical to my original gray. There is some slight loss, I now 
have 28,871 levels in each channel, however the end points are intact and they appear identical to my original Gray on the 
monitor, relationships are intact.
Temporarily working with one (Y) channel, via levels or curves we pull 25% to 100%. So the entire range of the channel, from 
0 - 100%, is filled with the top 25% tones of our original file. The Levels utility now 
tells me I've lost some tones, I'm left with 7,540 in that channel. If I now send this channel to a driver that won't mux it up, 
and print it to one ink of an Epson, I'm using the full range of that output system's capability 
for one ink.
However, we have an ink there who's maximum density only comes to 25% of our output system/paper/ink combo's 
maximum density capability. It is also monochromatic.
I still have three channels left, each with 28,871 levels of image to manipulate and send to three more inks of varying 
densities to take over at 25% and continue on down the scale. With the severe curves 
necessary to properly partition, each channel will probably wind up with something more like 7000 levels, and each is 
given it's own part of the scale. Clearly I wind up with a lot of levels at the end of it. Even if I 
have to convert to 8 bit for the printer to accept it I will have more than 256, and none of it has anything to do with hue or 
chroma in this particular discussion. These channel's levels, because of the 4 differing inks 
and correct partitioning, wind up serial, not parallel, to a large degree.
How many levels do we actually wind up with as ink on paper? I don't know. Is it all "real" or is some of it noise? Maybe, but 
it is all tonal information derived from the original file. Do we need this much info, can 
we see it? I don't know that either, and that's not what I was addressing.
This is hypothetical, the inks are never really 25%, 50%, 75%, 100%. We have channel/ink overlap to deal with for smooth 
transitions, and different paper and ink combinations require one to deviate from this 
ideal in different ways. But this is one of the main reasons quad tones look so good, we are assigning a full scale to an ink of 
limited density, resulting in a long scale on paper before you even move on to the next 
ink. You have to look at his as a system (which even includes the paper), not just a file.
How the Piezo driver accomplishes this is probably different. It may not actually convert the file to four channels in the 
background, but it certainly assigns levels from the original single channel file to four different 
inks in a very similar fashion. Jon actually taught these methods of manual quads before he offered the R9 as Piezography, 
and the R9 was commercially available before his agreements with them. They offered 
it as a straight colorsync compatible CMYK export module and also a quad version. It's clearly a four channel driver.
So now that my testosterone is burned off, I need to get back to making prints with thousands of tones.
Tyler