QTR-Quadtone RIP

Howard, thanks for the advice.  The ink limit in the HPR curve I've
been working from is 75%.   When I measure around that point on a the
ink limit calibration chart at 100% I get:

Step     L*
50       17.5
55       17.8
60       18.2
65       18.4
70       18.6
75       18.8     ==> Chosen as ink limit
80       18.8
85       19.0
90       18.8
95       19.4
100      19.5

As you suggest, the 75% step is very close to the 80->100 steps, and
the 70% step too.

Based on this data, what ink limit would you try as a base.

Cheers, --Kip


--- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:
>
> Kip Cole wrote:
> > I have finally been able to dedicate my old 2100 to QTR and am
> > starting with standard UC until I get comfortable with curve creation
> > in a "2k" system.
> > 
> > I am trying to create a warm curve for HPR.  I have tried as a base
> > curve the EEM curve in the QTR distribution and also Mr. Schofields
> > HPR curve at
> >
http://homepage.mac.com/WebObjects/FileSharing.woa/wa/default?user=scho&templatefn=FileSharing2.html&xmlfn=TKDocument.2.xml&sitefn=RootSite.xml&aff=consumer&cty=US&lang=en
> > I am creating step wedges of non-linearised curves in all cases.
> > 
> > For all my tests I'm getting density reversal in the 100% step (using
> > the 21step.tif file).  I'm getting around 19.1 to 20.2 L* in this step
> > depending on my adjustments, and a good ramp from around 18.5 L* on
> > the other steps.  All measured with EyeOne/MeasureTool.
> > 
> > Have tried adjusting black boost, gray overlap (even up to 100%),
> > shadow adjustment but to no avail - the 100 step is always lower
> > density. The curve uses only Mk and Lk as you would expect.
> > 
> > I know this is a little trial and error involved but after about 20
> > experimental step wedges I figure some advice and guidance would sure
> > be appreciated,
> > 
> 
> Kip
> 
> I would suspect the ink limit on K. What are the readings for K on the 
> calibration strip for the limit you have used and the two steps either 
> side? Sometimes it's worth pulling the limit a little back from the 
> maximum dmax step to make sure you have good separation between the
step 
> at the limit and the step before it. The maximum can then be 
> re-introduced via black boost.
> 
> You could also try an overlap of 0 if you haven't tried that yet.
> 
> Howard
>