QTR-Quadtone RIP

Phil: Have you printed Keith Coopers test image
<http://www.northlight-
images.co.uk/article_pages/black_and_white_test.html>
and looked at the circular gradient and printed the offsetgrad8.jpg 
file located in this group's Files section to see if you can 
actually see the non-linearities you are measuring?

Another thing to try is a 51 step calibration approach using the 51-
step file in the OneEye folder of the QTRip folder.  I had problems 
getting a linear profile using the 21-step approach, but the 51-step 
approach worked very well for me.  YMMV.

BTW, I stretched the 51step image to print landscape -- bigger 
patches for my clumsy hands.


--- In QuadtoneRIP@yahoogroups.com, "Philip Schwartz" <pschwart@...> 
wrote:
>
> Thanks Terence. I am a new to QTR but have lots of experience 
printing
> fine art B&W. QTR has lots of controls, but they are not well
> documented so results are often not predictable, making the 
profiling
> process incredibly tedious. I am spending far too much time 
profiling,
> and not enough time creating and printing images :( Hoping this 
will
> change ...
> 
> --- In QuadtoneRIP@yahoogroups.com, Terence Lowe <televe@> wrote:
> >
> > I, too struggled with the QTR linearization process.  My approach
> was to 
> > try to get the best density measurements by modifying the ink 
setup and 
> > grey curve tabs, but with the linearization array clear.  This 
took
> many 
> > iterations.  Eventually, when I thought that the measured 
density curve 
> > was close to the ideal density curve (I plotted both in Excel 
for 
> > comparison purposes), I linearized, printed the step tablet 
again and 
> > checked the new, linearized density measurements to confirm (or 
> > otherwise) that my final curve was good enough.
> > 
> > I made the assumption that it was incorrect to re-linearize the 
> > linearized curve during the many iterations and so only 
linearized once 
> > as the final step in curve creation..  I hope this was the 
correct 
> > assumption.
> > 
> > Cheers,
> > 
> > Terence Lowe.
> >
>