Digital BW, The Print

I'm not the most experienced QTR profiling person, but I've been seeing what
might make the process faster and more accurate from my perspective.  Here
are a couple of things I've found that might become part of my general QTR
profiling procedure.

 

First, I think a smooth are relatively linear carbon core is needed.  I
think a linear core makes for more even toning and a more linear final
result.  I was not satisfied that the QTR controls in the gray tabs were
sufficient.

 

So, what I've found works rather well is to use QTR's partitioning
procedure, but when the Create Curve button is pushed, use a screen grab to
copy the curves.  Then go to Photoshop and simply copy those curves'
coordinates to *.acv curves.  The PS curves can then be rather easily
refined to achieve an excellent carbon core.  These PS curves are imported
back into QTR for the individual gray inks. The resulting linear (even
before final linearization) core is then used for all the profiles for that
type of paper.  

 

This basically gives us perfectionists the advantages of Roy's partitioning
algorithm as a starting point, but with none of it's limitations.

 

The second thing I've found very useful is to set the LC and LM (toner) ink
limits by simply printing a few 50% patches with straight line curves for LM
and LC.  This is very fast.  The straight line curves are simply entered
into the Points List tab as (0, 0) and (100, 100).

 

Once the 50% patch is the tone I want, the curve is simply turned around at
about 85% to 90% so that the curve ends at (100, 0).  By getting the light
inks out of the 100% patch, the dmax is increased about 0.05 - worth the
effort.  I use *.acv curves to be sure the turn around is smooth.  I stick
some points at (25, 25), (50, 50), and (75, 75) to be sure the "curve" stays
straight for the most part and the same as the (0, 0) to (100, 100) initial
test curve.  The PS curves can be used by QTR or the points can be put into
the Points List tab to make future modifications easier.  (It's easy to lose
track of PS curves that are not accessible from the QTR profile itself, and
other users would not have the originals.)  Many will simply linearize these
basically straight line curves and be done with it.  Others (like me) will
find tweaking a bit worth the effort for some purposes.

 

Paul

www.PaulRoark.com <http://www.paulroark.com/>  

 



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