Digital BW, The Print

Hi, Paul!

Thank you very much for your explanation. It is getting a bit 
clearer for me :).

First of all I have just realized that although I have downloaded 
and instaled the most recent QTR version, somehow the QTR-Create-ICC 
RGB had remained from an earlier version 2.4.2.0, (the latest one 
being 2.5.1.0)  I will see if I can clean the installation and have 
the latest version installed.  Perhaps using the new version my 
shadow problem goes away - although the release notes do not refer 
to any improvements in QTR-Create-ICC RGB.  
 
> With my curves on the AdobeRGB version of the file, your 50% test 
patch has
> a Lab L of 61. That's a bit light.  A strictly linear response, 
which is
> close to what the curves were originally made for, would be half 
way between
> the paper white and 100% black.  That point is L = 56. (Note that 
my old
> target was density = 0.61, which would be about L 56.6.)

I guess this means that if I stay with the curves approach, I would 
ideally need to adjust the curves to make the response more linear, 
right?

> Yes, Gray Gamma 2.2 is not linear and the old curves target was 
more linear.
> But the ICC should -- if the monitor is calibrated and the systems 
are
> working right -- make a print that matches the monitor better than 
the old
> curves.  

I have a calibrated monitor with spyder at 6500K and Gamma 2.2 and I 
would say that I get a better match with the old curves approach.  
The shadows in the prints are just compressed too much.  But I 
digress :).


> 
> With the ICC, your 50% patch is L = 54.  I think that's about 
right.

Yes, this I confirmed by printing real images - I think there is 
improvement in the midtones in prints made with ICC. It is only in 
90-100% range that the problem starts. 


> In fact, with the ICC the ramp is very linear to 90%.  Then the 
problem is
> that 90% to 100% has very little separation.  The 50% to 100% 
usually has
> very little separation in Gray Gamma 2.2.  The 90% to 95% is, 
however, less
> than I would expect.  I'm guessing that the Create ICC RGB program 
is simply
> working with too little information about what is going on in the 
deep
> shadows.  It's probably assuming a straight line response between 
the 95%
> and 100% input points when, in fact, the output gets much darker 
sooner than
> the program assumes. 
> 
> I'm not sure if the Create ICC programs will accept 51 step 
inputs, but most
> of QTR will.  That might get enough information to the program to 
correct
> the problem.  Be sure to print the target vertically, as I've 
found it more
> accurate that way.  
 
I will give the 51-step wedge a try.  Can I use the one that is 
included with the Quadtone RIP Eye-One folder?


> A correction layer is just a way to
> use older files (edited for linear spaces) in GG 2.2 (or vice 
versa) without
> having to re-edit the files.  I wish all our workflows, spaces, 
etc. were
> consistent, but they just are not.  

> If the curves work for you and match your monitor, then by all 
means stay
> with that workflow.  

I will give the correction layer a try. If it works I will have to 
see if and how it could fit in the workflow.  The reason that I am 
interested in icc approach in the first place is simplification of 
the process - using icc instead of curves would make printing so 
much easier from Qimage (that I have just "discovered") or 
eventually maybe even from Lightroom when the printing end of that 
application improves. 


Thanks for all the help so far. I will report on my further progress 
with this.

Best regards

Didzis