Digital BW, The Print

I doubt the dMax is much different - same with the grain.  QTR is really
very smooth although we still don't know which printer is being used. I
suspect the real issue is either a poor QTR curve or lack of use of a QTR
Create ICC profile, or both.  The latter, the old QTR way, will produce a
relatively flat print simply because of the linearity of the printer.  But
if you profile that linearity with QTR Create ICC (which is effectively what
you are doing when you make and use a colour profile except that the QTR ICC
profile is simply for the luminance axis) then you get a better fit of the
image into the reduced dynamic range of the printer.  This last part is a
critical difference between the two methods described.  If David is not
using QTR Create ICC it's like he's only using half the RIP.


> From: "Paul D. DeRocco" <pderocco@...>

> 
> Well, sure. The Epson driver uses a mix of color inks to achieve gray tones,
> which means that you get less grain. You also get metamerism (the green cast
> under daylight), and faint color shifts at different gray levels. QTR uses
> mostly black ink (including light black), and only mixes in the minimum
> amount of color inks needed to tweak the tone. The result will always be a
> little more grainy because you're trading three dots of each color for one
> dot of black. But there won't be any metamerism. (Using 1440dpi may be a
> little to blame as well.)
> 
> As to the density of the blacks, it's entirely possible that the QTR curve
> has room for improvement. But the point of QTR is that you can experiment
> and make curves. It's theoretically possible to tell QTR to put out the same
> amount and combination of inks that the Epson driver does. Curves are best
> built with the aid of a colorimeter, or at least a densitometer, to read the
> patches in a test step wedge, but you may be able to coax denser blacks out
> of the existing curves by fiddling with them.
> 
> If you really want the smoothest tones, with no metamerism, you need to
> switch to quadtone or hextone inks, which have multiple densities of gray.
> QTR is really designed for these.
> 
> --
> 
> Ciao,               Paul D. DeRocco
> Paul                mailto:pderocco@...
> 
> 
> 
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