Digital BW, The Print

Richard,

Sorry I was not able to get to this yesterday.  

>I'm trying to figure out how to make custom curves for my 
>2200 and UT-3D inks. I've downloaded Paul's 21-step-K220.tif 
>test file since I'm getting a dMax of 2.20 on Costco glossy paper. 
>On his image he has what each square's density should be,

What density they "should" be depends of the working space and other
variables, and they've changed since I posted most of those test strips.

> so for example he has 0.61D for the 50% patch.

My older curves were made to be consistent with the Piezo system I started
with.  That was not a color managed system.  As a practical matter the 50%
point was the mid-point between the typical matte paper white and dmax. 

When the MIS inksets were able to print on glossy paper, I felt it was
better and more consistent to have the additional dmax absorbed totally by
shadow densities.  This is contrary to the "color managed" approaches that
slide the 50% point up and down with the dmax. So, the 50% point stayed the
same for the curves I made for the old UT2 and UT7 inksets.

The UT-3D approach, using Roy's QTR Create-ICC-RGB is, more or less, a
"color managed" approach where the monitor and print densities will be set
by the working space selected.  I agree with David that Gray Gamma 2.2 makes
the logical standard.  In fact, I'm even using that when I use the non-color
managed IJC rip.  I use an adjustment layer to coordinate the two.

I have slightly updated my test files at
http://home1.gte.net/res09aij/Test-files.htm to include 21-step test files
that would be appropriate for typical matte and glossy papers.  Those test
strips have "GG22" in their file names.  (The densities that I show are
based on my empirical readings of such test strips.)

> On the QTR site there is a page that lists "Ideal
> Densities for Various dMax" which shows a 0.682D for the 50% 
> for a gamma of 2.20. 

Roy's chart is no doubt more complete and accurate than my test strip
readings.  With Create ICC, I just eyeball the test strips, get the points
that I've shown number for close, and let the software do the rest.

> Is there some web site or reference work that explains all of this?

I'm not sure.  I've had to read lots of different things to get a handle on
it all, and I'm sure not an expert in color management.  I think posting a
question here is the best source of information. 

> I'd like to be able to print the same image onto different papers 
> and have them look similar.

I agree.  While I initially thought it was better to keep the 50% gray the
same, fighting industry standards -- color management, Gray Gamma 2.2, etc.
-- just does not seem worth it.  The "old days" of having to make custom dot
gain curves to match the monitor to the print were not "good old days."  

Epson has posed the same question to me, and my response was that color
management seems to be the best way to get uniformity among systems and
approaches.  Otherwise we end up with the proverbial Tower of Babel where
files edited with one system can't be printed on another.  The huge color
printing world went through this exercise long ago, and the existing color
management system is what they came up with.  Our little B&W niche, as
usual, probably should ride the coattails of the color world to the extent
possible.  

That said, I still make test prints and use them for final adjustments.
I've found the color management systems are not totally accurate, nor can
they take into account unknown variables such as the glass used in framing. 

Hope this helps.

Paul
www.PaulRoark.com