QTR-Quadtone RIP

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,

Regards,

--Kip

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

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
>

In case others are interested, I took Howard's advice and I wound back
the ink limit to 55% (where there is a clear step to either side). 
Re-partioned the gray ink and adjusted its limit.  Resultant wedge was
good.  It linearised fine and the resulting dMax is 1.59. More
important to me is a nice smooth gradiant.

Now for the cool curve.......

Cheers, --Kip

--- In QuadtoneRIP@yahoogroups.com, "Kip Cole" <kipcole9@...> wrote:
>
> 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
> >
>

Kip Cole wrote:
> 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
> 
Kip
Those figures look a bit peculiar - they seem to go backwards which 
would indicate over-inking. Are you printing at 1440 or 2880dpi? If at 
2880 you may want to drop the limit even more than the 55% you have 
suggested in your other email. I don't use the UC inks but I would have 
thought you should be able to achieve a better dmax than 1.59 on HPR. 
Eboni ink typically gives 1.68-1.72.

regards
Howard

Howard, I'm an plonker.  I was indeed printing at 2880.  When I went
back to 1440 all is OK.  I don't get more than 1.6 dMax at the moment
but thats OK - will move to K6 or a K4+toner solution sooner rather
than later now that I have overcome most of the dumb mistakes.

Thanks indeed for your help and patience,

--Kip


--- In QuadtoneRIP@yahoogroups.com, Howard Shaw <glassman@...> wrote:

>
> Kip Cole wrote:
> > 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
> > 
> Kip
> Those figures look a bit peculiar - they seem to go backwards which 
> would indicate over-inking. Are you printing at 1440 or 2880dpi? If at 
> 2880 you may want to drop the limit even more than the 55% you have 
> suggested in your other email. I don't use the UC inks but I would have 
> thought you should be able to achieve a better dmax than 1.59 on HPR. 
> Eboni ink typically gives 1.68-1.72.
> 
> regards
> Howard
>