QTR-Quadtone RIP

having printed the initial Ink separation page and selected 80% as
the overall Ink limit, for a given Ink/Paper combination in 
question; I then print a second Ink separation page (in calibration 
mode of course) with the Ink limit slider set to 80%.

question:

the initial overall Ink limit of 80% was chosen because the black 
ink maxed out at 80%, however non of the other inks maxed out on the 
initial 100% ink separation printout. So when I produce my second 
Ink separation page (in calibration mode) with the Ink limit slider 
set to 80%, the black ink is printed as one would expect (with a nice
gradual increase in density, until it max's out at 100,) however, 
because I have set the ink limit to 80%, all the other inks printout 
with a reduced density when their individual densities where fine 
with the initial 100% Ink separation page.

So should I set the default ink limit in QTR curve creation to 100% 
(so all the other inks are at their max,) and set the Black ink 
limit to 80% as established above.

Hope somebody understands what I'm getting at, and I would like to 
hear if anybody builds curves with this approach, or does everbody 
follow Tom Moore's excellent user guide procedure, which sets the 
overall hardware ink limit to all inks (if I understand it 
correctly,)

regards,

Jamie Creed

There was some discussion of this in the past few months. I'm not sure if it
was on this list or the BW printing list. The most active participant was
Steve Kale. The essence of it was to print several inkseparation pages each
limited for the particular grey or toner ink in question. The goal was to
use each ink (grey or toner) to its fullest in order to minimize dots in the
transitions. I don't recall the procedure in detail and don't do it myself.
I also have not seen any comments on the results of this approach. 

More comments below...

> -----Original Message-----
> From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] On
> Behalf Of Jamie Creed

...snip...

> 
> the initial overall Ink limit of 80% was chosen because the black
> ink maxed out at 80%, however non of the other inks maxed out on the
> initial 100% ink separation printout. So when I produce my second
> Ink separation page (in calibration mode) with the Ink limit slider
> set to 80%, the black ink is printed as one would expect (with a nice
> gradual increase in density, until it max's out at 100,) however,
> because I have set the ink limit to 80%, all the other inks printout
> with a reduced density when their individual densities where fine
> with the initial 100% Ink separation page.
> 
> So should I set the default ink limit in QTR curve creation to 100%
> (so all the other inks are at their max,) and set the Black ink
> limit to 80% as established above.

If you set the default ink limit to 80, you can always set the limit of any
individual ink (toner or grey) to a different limit - larger or smaller than
the default. Or, you can do what you suggest. In the end you need to be able
to tell QTR what the density of each ink is as a percentage of black at its
limit.

The consequence of setting too low a limit (by a few percentage points) is
not that great (IMHO). The curve can still be linearized. You might see a
few more dots in the transitions but I'm not convinced and haven't seen any
results. There will still be transitions with dots, just at a slightly
higher density.

> 
> Hope somebody understands what I'm getting at, and I would like to
> hear if anybody builds curves with this approach, or does everbody
> follow Tom Moore's excellent user guide procedure, which sets the
> overall hardware ink limit to all inks (if I understand it
> correctly,)

Well the guide might not be as excellent as you state if it implies that you
set the overall ink limit to all inks. There are many reasons that one might
have for setting a limit other than the default. The default limit is
basically a convenience.

> 
> regards,
> 
> Jamie Creed
> 


Tom Moore

I don't think there's an absolute answer.  Certainly you can set each one separately
but for the grays I doubt you'd ever be able to tell the difference.  Linearization
will eventually get all the densities right regardless of what you set.  It's more
critical for black since that determines dMax but in general I'd usually use the
same for all the grays.  The toner inks on the other hand would probably
have specifically picked limits to get the right hue.

Roy


--- In QuadtoneRIP@yahoogroups.com, "Tom Moore" <r.t.moore@r...> wrote:
> There was some discussion of this in the past few months. I'm not sure if it
> was on this list or the BW printing list. The most active participant was
> Steve Kale. The essence of it was to print several inkseparation pages each
> limited for the particular grey or toner ink in question. The goal was to
> use each ink (grey or toner) to its fullest in order to minimize dots in the
> transitions. I don't recall the procedure in detail and don't do it myself.
> I also have not seen any comments on the results of this approach. 
> 
> More comments below...
> 
> > -----Original Message-----
> > From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com] 
On

> > Behalf Of Jamie Creed
> 
> ...snip...
> 
> > 
> > the initial overall Ink limit of 80% was chosen because the black
> > ink maxed out at 80%, however non of the other inks maxed out on the
> > initial 100% ink separation printout. So when I produce my second
> > Ink separation page (in calibration mode) with the Ink limit slider
> > set to 80%, the black ink is printed as one would expect (with a nice
> > gradual increase in density, until it max's out at 100,) however,
> > because I have set the ink limit to 80%, all the other inks printout
> > with a reduced density when their individual densities where fine
> > with the initial 100% Ink separation page.
> > 
> > So should I set the default ink limit in QTR curve creation to 100%
> > (so all the other inks are at their max,) and set the Black ink
> > limit to 80% as established above.
> 
> If you set the default ink limit to 80, you can always set the limit of any
> individual ink (toner or grey) to a different limit - larger or smaller than
> the default. Or, you can do what you suggest. In the end you need to be able
> to tell QTR what the density of each ink is as a percentage of black at its
> limit.
> 
> The consequence of setting too low a limit (by a few percentage points) is
> not that great (IMHO). The curve can still be linearized. You might see a
> few more dots in the transitions but I'm not convinced and haven't seen any
> results. There will still be transitions with dots, just at a slightly
> higher density.
> 
> > 
> > Hope somebody understands what I'm getting at, and I would like to
> > hear if anybody builds curves with this approach, or does everbody
> > follow Tom Moore's excellent user guide procedure, which sets the
> > overall hardware ink limit to all inks (if I understand it
> > correctly,)
> 
> Well the guide might not be as excellent as you state if it implies that you
> set the overall ink limit to all inks. There are many reasons that one might
> have for setting a limit other than the default. The default limit is
> basically a convenience.
> 
> > 
> > regards,
> > 
> > Jamie Creed
> > 
> 
> 
> Tom Moore

Cheers Tom and Roy for the clarification and the info.

Tom my own opinion of your User Guide is that it is an absolute 
senior partner to QTR, pulling together all sorts of info, and it 
really gave me a kick start when I began down this route to Black & 
White heaven, I found your procedure was well laid out and easy to 
follow. I guess I just wanted to establish in my own mind if there 
was an inherent reason why I shouldn't use separate ink limits; I 
guess there isn't and I'm going to give it a try.

Roy (and Steve), what can I say about QTR: it's the business, thanks 
guys,

regards,

Jamie Creed

--------------------------------------------------------------------


--- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" wrote: ---
> 
> I don't think there's an absolute answer.  Certainly you can set  
> each one separately but for the grays I doubt you'd ever be able  
> to tell the difference.  Linearization will eventually get all the 
> densities right regardless of what you set.  It's more critical   
> for black since that determines dMax but in general I'd usually   
> use the same for all the grays.  The toner inks on the other hand 
> would probably have specifically picked limits to get the right   
> hue.
> 
> Roy
> 
> 
-------------------------------------------------------------------


> --- In QuadtoneRIP@yahoogroups.com, "Tom Moore" wrote: ---

> > There was some discussion of this in the past few months. I'm 
not sure if it was on this list or the BW printing list. The most 
active participant was Steve Kale. The essence of it was to print 
several inkseparation pages each limited for the particular grey or 
toner ink in question. The goal was to use each ink (grey or toner) 
to its fullest in order to minimize dots in the transitions. I don't 
recall the procedure in detail and don't do it myself.
> > I also have not seen any comments on the results of this 
approach. 
> > 
> > More comments below...
> > 
> > > -----Original Message-----

     on Behalf Of Jamie Creed


> > ...snip...
> > 
> > > 
> > > the initial overall Ink limit of 80% was chosen because the 
black ink maxed out at 80%, however non of the other inks maxed out 
on the initial 100% ink separation printout. So when I produce my 
second Ink separation page (in calibration mode) with the Ink limit 
slider set to 80%, the black ink is printed as one would expect 
(with a nice gradual increase in density, until it max's out at 
100,) however, because I have set the ink limit to 80%, all the 
other inks printout with a reduced density when their individual 
densities where fine with the initial 100% Ink separation page.
> > > 
> > > So should I set the default ink limit in QTR curve creation to 
100% (so all the other inks are at their max,) and set the Black ink
limit to 80% as established above. If you set the default ink limit 
to 80, you can always set the imit of any individual ink (toner or 
grey) to a different limit - larger or smaller than the default. Or, 
you can do what you suggest. In the end you need to be able to tell 
QTR what the density of each ink is as a percentage of black at its 
limit.
> > 
> > The consequence of setting too low a limit (by a few percentage 
points) is not that great (IMHO). The curve can still be linearized. 
You might see a few more dots in the transitions but I'm not 
convinced and haven't seen any results. There will still be 
transitions with dots, just at a slightly higher density.
> > 
> > > 
> > > Hope somebody understands what I'm getting at, and I would 
like to hear if anybody builds curves with this approach, or does 
everbody follow Tom Moore's excellent user guide procedure, which 
sets the overall hardware ink limit to all inks (if I understand it
correctly,) Well the guide might not be as excellent as you state if 
it implies that you set the overall ink limit to all inks. There are 
many reasons that one might have for setting a limit other than the 
default. The default limit is basically a convenience.

> > 
> > > 
> > > regards,
> > > 
> > > Jamie Creed
> > > 
> > 
> > 
> > Tom Moore

I have tried the approach Steve described and believe it has merit for those
who like to tinker.
I use it slightly differently however; I limit some of the grays well below
their ink limit to move the location of the transitions.  This was helpful
for utilizing more of the light FS-Y in UT7 curves, which reduces the darker
dots in the highlights.  I'm still playing, experimenting with different
approaches, and so on.

Best regards,
John Moody

-----Original Message-----
From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com]On
Behalf Of Tom Moore
Sent: Thursday, September 22, 2005 11:16 PM
To: QuadtoneRIP@yahoogroups.com
Subject: RE: [QuadtoneRIP] Characterizing the Ink / Paper combination
(Overall Ink Limit)

There was some discussion of this in the past few months. I'm not sure if it
was on this list or the BW printing list. The most active participant was
Steve Kale. The essence of it was to print several inkseparation pages each
limited for the particular grey or toner ink in question. The goal was to
use each ink (grey or toner) to its fullest in order to minimize dots in the
transitions. I don't recall the procedure in detail and don't do it myself.
I also have not seen any comments on the results of this approach.