Digital BW, The Print

I'm trying to create a QTR curve, but when I linearize, the density of the
100% patch in my step wedge drops dramatically -- depending on settings, 
from 1.64 down to as low as 1.50.

Has anyone seen this before? Shouldn't linearization pin the 0 and 100%
ends of the curve and only adjust points in the middle?

BTW, in some cases, the linearized 100% patch has very fine banding that
looks with the naked eye as if it's in the direction of the printhead, but on
examination with a loupe, appears to be small white dots arrayed on lines
perpendicular to the printhead movement. I'm guessing that this is just the
result of the ordered dither, and is consistent with the hypothesis that less
ink is being used than should be. I don't ever see this banding at 95%, which 
I assume is because the second ink comes in there. Does that sound right?

Some details: I'm using the latest version of QTR on OS X with an Epson 2200
printer, MIS UT7 inks and Moab Entrada Natural paper. I have BOOST_K set to 
100, and GRAY_OVERLAP set to 0; other settings of these variables give lower
dmax prior to linearization.

--Daniel

Try sending this to the QTR group, or directly to Roy Harrington.
   
  Tom Baker
  

daniel <dnj@...> wrote:
          I'm trying to create a QTR curve, but when I linearize, the density of the
100% patch in my step wedge drops dramatically -- depending on settings, 
from 1.64 down to as low as 1.50.

Has anyone seen this before? Shouldn't linearization pin the 0 and 100%
ends of the curve and only adjust points in the middle?

BTW, in some cases, the linearized 100% patch has very fine banding that
looks with the naked eye as if it's in the direction of the printhead, but on
examination with a loupe, appears to be small white dots arrayed on lines
perpendicular to the printhead movement. I'm guessing that this is just the
result of the ordered dither, and is consistent with the hypothesis that less
ink is being used than should be. I don't ever see this banding at 95%, which 
I assume is because the second ink comes in there. Does that sound right?

Some details: I'm using the latest version of QTR on OS X with an Epson 2200
printer, MIS UT7 inks and Moab Entrada Natural paper. I have BOOST_K set to 
100, and GRAY_OVERLAP set to 0; other settings of these variables give lower
dmax prior to linearization.

--Daniel



         


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