QTR-Quadtone RIP

Apologies if I give two similar replies. At the time of the first 
reply I had not signed up yet an perhaps it does not appear.....

Hi Tom,

I'm still in the epxerimenting phase with QTR (windows XP, Photoshop 
CS2, Epson 2100, UC inks, Epson Enhanced Matte). With help of your 
excellent User Guide I have been able to get started very quickly.. 
Thanks!

There are however a few things that I can not get my head around yet. 
I found another recent thread that relates to it, but perhaps it fits 
better with this old post of yours.

I think by now I understand the "front-end" part of profiling. 
Convering to Gray-Lab linearizes the document and monitor (if 
properly calibrated) to the LAB space. Right?

What I don't understand yet is the "back-end"/printer part. I see 
also some differences between your workflow and Roy Harrington's flow 
as described in the "gray-readme.doc" file contained in the GTR 
installation.

When it comes to printing Roy states:

"For Windows where it is necessary to save a tiff-file, you should 
Convert to Profile using either the Gray Matte Paper or Gray Photo 
Paper. Then save the file for printing in QTR Gui".

I don't understand this. As I understand it, QTR linearizes against 
LAB. I would expect any differences between matte and glossy papers 
already to be accounted for in the QTR curves. So why would one need 
to convert before printing in QTR? 

I find support for this point of view in your workflow. I understand 
you use the Gray Matte and Gray Photo profiles for soft-proofing. But 
I don't see you actually saving a converted file fo printing. Am I 
correct?

To get some more understanding, I did two tests. For the first I 
printed a number of test wedges with Photoshop CS2 + QTR in different 
spaces (dot gain 20%, gamma 2.2, gray-lab) each of them both 
with "assign profile" and "convert to profile". To my surprise I did 
not see any difference whatsoever (visual inspection only, I have 
photospectrometer yet). In the second test I compared your workflow 
(as I understood it, so leaving the document converted to Gray-lab) 
and conversions to gray-matte and gray-photo. Again no visual 
differences (at least not to my untrained eye).

Should this test be correct indeed? Are do I miss something? If it's 
right it could explain why both your and Roy's workflow are correct. 
But then Roy's would be unnecessarily complex, which I find difficult 
to believe.

The good news is that my monitor and prints seem to match quite well. 
I have to do some more tests under better viewing circumstances. 


Sorry for the long post. It was already difficult to express my 
question in this way, let alone in shorter one ;-)

Thanks in advance,

Joost