QTR-Quadtone RIP

I am currently working on a curve using an Epson 1400 w/ UT14 inks on Ilford Galerie 
Gold Fibre Silk, and I am in the process of trying to maximize the dmax.  The inksets are 
as follows:

ink 1 K = Eboni Black
ink 2 C = Cool PK
ink 3 M = Warm PK
ink 4 Y = GLOP
ink 5 LC = Dilute Cool PK
ink 6 LM = Dilute Warm PK

Here is my dilemma, I selected a ink limit visually at 40% (2.27) without the aid of the 
densitometer readings, but the dmax actually occurs at about 70% (2.39) according to the 
densitometer readings.  Since this is a glossy paper, the Eboni in the K position is not 
used.  So this is all done with the Photo Black inks in the C, M, LC, and LM positions.  I 
printed out the inkseparation image at 40% and determined my ink crossover points. 
 Then I printed out the 21 step image and predictably the 100% black was low at around 
2.20.  I thought I could boost the photo black in the C position to get close to the 
maximum dmax I had achived earlier at around (2.39); so in the script I changed the 
"Boost K" to "Boost C" thinking that this would boost the PK in the C position.  However 
when I printed the 21 step, I could tell that Eboni was being used in the 100% square.

Therefore, my question is, is there a way to boost the PK in the C position without using 
the Eboni in the K position?  I wasn't planning on using the Eboni with the addition of 
GLOP as I felt that a dmax close to 2.39 would be pretty good, so why complicate things; 
and I have no idea what kind of dmax the Eboni with GLOP would produce.

What I am going to try next, unless anyone has a better suggestion is to increase the ink 
limit on the Cool PK and recalculate the crossover points.  My only fear of doing this is that 
the blacks in the deep dark shadows may block up.

Any suggestions you may have will certainly be appreciated.

Thanks,
Randy

Randy, 
   The short answer to your question, I think, is that you can
increase the maximum ink from primary gray channel (C in this case) by
increasing the overall default ink limit.  There shouldn't be any
think from the K channel unless you have specified it.

I have also made a set of curves for the UT-14 inkset and Gold Fiber
Silk, which are available here in the "Files" section.  The highest
density I obtained was about 2.2, with an ink limit of about 40%, just
as you estimated visually.  This makes me wonder whether your
densitometer might be leading you astray.  I did not use a
densitometer, per se, but used a flat bed scanner that I had
calibrated with a Kodak step tablet.  The calibration tablet only goes
to 2, though, so it could be that the exact values at higher densities
might not be correct.  But, from my experience I would be very
surprised if the density really increases much with inkloads greater
than about 40%.

I would be interested to hear if you have tried my curves for this system.

Hope this helps,
David

--- In QuadtoneRIP@yahoogroups.com, "Randy Rancier"
<randy_rancier2004@...> wrote:
>
> I am currently working on a curve using an Epson 1400 w/ UT14 inks
on Ilford Galerie 
> Gold Fibre Silk, and I am in the process of trying to maximize the
dmax.  The inksets are 
> as follows:
> 

> Here is my dilemma, I selected a ink limit visually at 40% (2.27)
without the aid of the 
> densitometer readings, but the dmax actually occurs at about 70%
(2.39) according to the 
> densitometer readings.  Since this is a glossy paper, the Eboni in
the K position is not 
> used.  So this is all done with the Photo Black inks in the C, M,
LC, and LM positions.  I 
\in the 100% square.
> 
> Therefore, my question is, is there a way to boost the PK in the C
position without using 
> the Eboni in the K position?  I wasn't planning on using the Eboni
with the addition of 
> GLOP as I felt that a dmax close to 2.39 would be pretty good, so
why complicate things; 
> and I have no idea what kind of dmax the Eboni with GLOP would produce.
> 
> What I am going to try next, unless anyone has a better suggestion
is to increase the ink 
> limit on the Cool PK and recalculate the crossover points.  My only
fear of doing this is that 

> the blacks in the deep dark shadows may block up.
> 
> Any suggestions you may have will certainly be appreciated.
> 
> Thanks,
> Randy
>

Thanks David for your reply; sorry I haven't replied before now, but I've been busy learning 
and figuring out QRT and some of it's idiosyncrasies.

I did learn that you can boost other inks other than the one in the K ink slot of the printer, 
according to Roy.  I say this because I haven't tried it yet, because I didn't end up needing 
to.  I will post Roy's description on how to do this below.

But before I do I wanted to answer your question, yes I did download your profiles and 
tried them out.  I wanted to see what I could do and perhaps get a more customized 
profile for my total system and individual printer.  Please see my next post that I will 
labeled "Observations of interest to QTR users" for some of the details that I believe may 
be of interest to others as well, and the reason for a separate post.  But in a short I was 
able to get up to or close to a dmax of 2.30 with the UT14 inks and IGGFS paper.  What 
was really strange was how this was accomplished, so see my next post.  I will upload my 
profile in the near future and inform you directly when I do so; that way you can do a 
comparison if you like.

Here was Roy's reply directly to me concerning Boost:

"As far as BOOST_K is concerned it will work on the ink that is in GRAY_INK_1 i.e. the one 
with VAL=100.  So if that's where C is that's what will be boosted.  If you want no eboni (K) 
make sure K isn't in the profile somewhere and LIMIT_K=0"

Randy


--- In QuadtoneRIP@yahoogroups.com, "dpgoldenberg33" <dpgoldenberg33@...> wrote:

>
> Randy, 
>    The short answer to your question, I think, is that you can
> increase the maximum ink from primary gray channel (C in this case) by
> increasing the overall default ink limit.  There shouldn't be any
> think from the K channel unless you have specified it.
> 
> I have also made a set of curves for the UT-14 inkset and Gold Fiber
> Silk, which are available here in the "Files" section.  The highest
> density I obtained was about 2.2, with an ink limit of about 40%, just
> as you estimated visually.  This makes me wonder whether your
> densitometer might be leading you astray.  I did not use a
> densitometer, per se, but used a flat bed scanner that I had
> calibrated with a Kodak step tablet.  The calibration tablet only goes
> to 2, though, so it could be that the exact values at higher densities
> might not be correct.  But, from my experience I would be very
> surprised if the density really increases much with inkloads greater
> than about 40%.
> 
> I would be interested to hear if you have tried my curves for this system.
> 
> Hope this helps,
> David
> 
> --- In QuadtoneRIP@yahoogroups.com, "Randy Rancier"
> <randy_rancier2004@> wrote:
> >
> > I am currently working on a curve using an Epson 1400 w/ UT14 inks
> on Ilford Galerie 
> > Gold Fibre Silk, and I am in the process of trying to maximize the
> dmax.  The inksets are 
> > as follows:
> > 
> 
> > Here is my dilemma, I selected a ink limit visually at 40% (2.27)
> without the aid of the 
> > densitometer readings, but the dmax actually occurs at about 70%
> (2.39) according to the 
> > densitometer readings.  Since this is a glossy paper, the Eboni in
> the K position is not 
> > used.  So this is all done with the Photo Black inks in the C, M,
> LC, and LM positions.  I 
> \in the 100% square.
> > 
> > Therefore, my question is, is there a way to boost the PK in the C
> position without using 
> > the Eboni in the K position?  I wasn't planning on using the Eboni
> with the addition of 
> > GLOP as I felt that a dmax close to 2.39 would be pretty good, so
> why complicate things; 
> > and I have no idea what kind of dmax the Eboni with GLOP would produce.
> > 
> > What I am going to try next, unless anyone has a better suggestion
> is to increase the ink 
> > limit on the Cool PK and recalculate the crossover points.  My only
> fear of doing this is that 
> > the blacks in the deep dark shadows may block up.
> > 
> > Any suggestions you may have will certainly be appreciated.
> > 
> > Thanks,
> > Randy
> >
>