QTR-Quadtone RIP

I have been using the instructions you reference at http://www.quadtonerip.com/html/QTRdownload.html. They are very clear and I'm following them precisely. Still, I'm getting ICCs that print way too dark. 

I re-examined your Lab values for the Q-13 that you have posted at http://www.paulroark.com/BW-Info/Making_B-W_ICCs-1.pdf and realize that I was confusing the Lab values with the density values. The instuctions in QTR are consistent with your notes. 

My scans don't seem to be wildly off, so I just don't understand why the ICCs created following the QTR instructions using the Q-13 calibration scale always print overly dark. 

--- In QuadtoneRIP@yahoogroups.com, Paul Roark <roark.paul@...> wrote:
>
> My experience with these flatbed methods led me to conclude that the main
> thing that needed to be corrected was the general shape of the flatbed
> curve ("gamma" is a term I used in the PDFs).  To do this, the Kodak gray
> card (Lab L=50) was the easiest to use if doing this manually.  Thus I
> simplified the PDF noted below by making this one:
> http://www.paulroark.com/BW-Info/Making_B-W_ICCs-GrayCard.pdf .  One could
> do the same thing by using just the mid-gray point ("M") on the Q13.  Then,
> all you have to worry about is the midpoint and the ends of the 21-step
> test strip that was scanned (not the Q13).
> 
> In general, since Roy has now automated the process of using the full Q13
> in the QTR StepWedge Tool (see
> http://www.quadtonerip.com/html/QTRdownload.html ), I recommend using that
> system and its excellent PDF instructions for the best flatbed control with
> the full Q13.  For the manual method, I'd stick with the simple three point
> adjustment approach of
> http://www.paulroark.com/BW-Info/Making_B-W_ICCs-GrayCard.pdf .
> 
> Paul
> www.PaulRoark.com
> 
> 
> 
> On Mon, Dec 10, 2012 at 7:37 AM, remononaz1 <homershannon@...> wrote:
> 
> > **
> >
> >
> > I have been using the QTR Create-ICC tool for about a year and am pretty
> > comfortable with the process. Recently I attempted to use the
> > Create-ICC-RGB tool so that I could embed a color curve that I have
> > developed for using UT14 ink on glossy paper. This curve works very well if
> > it is manually loaded and then the image is printed using printer controls
> > and gamma 2.2 settings. Creating an ICC for this would allow me to print
> > the image without the Photoshop add-curve step, print out of applications
> > other than Photoshop and embed a more accurate grayscale ramp.
> >
> > When working through this I realized that my methodology (which works
> > pretty well) for the Create-ICC calibration step of the process was wrong.
> > I have been using a pasted-in 21-step scale added to the scanned image as a
> > layer, not a scanned Q-13 calibration scale scanned with the printed
> > stepwedge. I don't recall why I changed from the process described in the
> > instructions.
> >
> > When I realized this, I changed my process and began following the
> > instructions precisely, adding the Q-13 to my scan and then setting the
> > calibration panel for 20 steps, middle gray at step 7 and using the default
> > Lab values. The result of doing this is that all my created ICCs print
> > terribly dark with maximum black beginning at around the 15th step in the
> > 21-step scale. No messing around with the Lab values in the calibration
> > setup box seems to correct this.
> >
> > I went back and read many of the articles that have been written about
> > this process. I paid particular attention to Paul Roark's article
> > http://www.paulroark.com/BW-Info/Making_B-W_ICCs-1.pdf. In this article,
> > Paul discusses the Q-13 scale and notes that paper black is at the B mark,
> > not at the 20th step.
> >
> > What I am wondering is: When I use the Q-13 scale, should I be selecting
> > only the steps 0-16 before starting the Create ICC script and setting the
> > calibration panel settings to a 17-step ramp (A to B) with middle gray at
> > 7?
> >
> > Could calibrating off of the blacks that are darker than paper black be
> > throwing off my calibration?
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>