QTR-Quadtone RIP

Hello,

I am printing with an Epson 3800 loaded with UC K3 ink.
After determining the ink limits and crossovers I printed a 21 step wedge in order to linearize it. For printing the wedge I have chosen the HPhotoRag-neut raw curve.
Unfortunately the highlights do have a green tint.
Also, the Dmax I reach is 1,51. According to Clayton Jones' website he measured a Dmax of 1,62 for the same ink/paper combination...

http://www.cjcom.net/articles/digiprn5b.htm#Soft Textured Art

I am not that experienced with QTR. So I appreciate any suggestion that may improve my results.

Stephan


Here's my curve so far (before linearization with ink limits and crossover values):

#  QuadToneRIP curve descriptor file
#
#  for ultrachrome k3 inks

N_OF_INKS=8
DEFAULT_INK_LIMIT=50

LIMIT_K=50
BOOST_K=55
LIMIT_C=5
LIMIT_M=3
LIMIT_Y=0
LIMIT_LC=6
LIMIT_LM=8
LIMIT_LK=37
LIMIT_LLK=35

#
#  Describe Usage of each Ink: K,C,M,Y,LC,LM,LK
#    All Inks of Printer must be listed
#

#
# Gray Partitioning Information
#
N_OF_GRAY_PARTS=3
GRAY_INK_1=K
GRAY_VAL_1=100

GRAY_INK_2=LK
GRAY_VAL_2=28

GRAY_INK_3=LLK
GRAY_VAL_3=9

GRAY_INK_4=
GRAY_VAL_4=

GRAY_HIGHLIGHT=6
GRAY_SHADOW=6

GRAY_GAMMA=1
GRAY_CURVE=

#
# Toner Partition Information
#
N_OF_TONER_PARTS=2
TONER_INK_1=C
TONER_VAL_1=100
TONER_INK_2=LC
TONER_VAL_2=30

TONER_HIGHLIGHT=6
TONER_SHADOW=6

TONER_GAMMA=1
TONER_CURVE="0;0 25;23 50;41 63;55 75;70 85;85 100;100"

N_OF_TONER_2_PARTS=2
TONER_2_INK_1=M
TONER_2_VAL_1=100
TONER_2_INK_2=LM
TONER_2_VAL_2=25

TONER_2_HIGHLIGHT=6
TONER_2_SHADOW=6

TONER_2_GAMMA=1
TONER_2_CURVE="0;0 23;20 50;45 63;60 75;77 100;100"

I think I was mixing things up.
Apart from the HPhotoRag-neut curve I printed also with the raw curve for matte papers. The raw curve produced slightly better highlights but still clearly tinted...
Do I have to split tone later with the cold curve in order get a fairly neutral tone?

As for the Dmax I have absolutely no idea how to improve it.

The wedge printed far more neutral with the ABW mode. And the Dmax slightly increased (1,55).


--- In QuadtoneRIP@yahoogroups.com, "siiaam" <s-i-a-m@...> wrote:

>
> Hello,
> 
> I am printing with an Epson 3800 loaded with UC K3 ink.
> After determining the ink limits and crossovers I printed a 21 step wedge in order to linearize it. For printing the wedge I have chosen the HPhotoRag-neut raw curve.
> Unfortunately the highlights do have a green tint.
> Also, the Dmax I reach is 1,51. According to Clayton Jones' website he measured a Dmax of 1,62 for the same ink/paper combination...
> 
> http://www.cjcom.net/articles/digiprn5b.htm#Soft Textured Art
> 
> I am not that experienced with QTR. So I appreciate any suggestion that may improve my results.
> 
> Stephan
> 
> 
> Here's my curve so far (before linearization with ink limits and crossover values):
> 
> #  QuadToneRIP curve descriptor file
> #
> #  for ultrachrome k3 inks
> 
> N_OF_INKS=8
> DEFAULT_INK_LIMIT=50
> 
> LIMIT_K=50
> BOOST_K=55
> LIMIT_C=5
> LIMIT_M=3
> LIMIT_Y=0
> LIMIT_LC=6
> LIMIT_LM=8
> LIMIT_LK=37
> LIMIT_LLK=35
> 
> #
> #  Describe Usage of each Ink: K,C,M,Y,LC,LM,LK
> #    All Inks of Printer must be listed
> #
> 
> #
> # Gray Partitioning Information
> #
> N_OF_GRAY_PARTS=3
> GRAY_INK_1=K
> GRAY_VAL_1=100
> 
> GRAY_INK_2=LK
> GRAY_VAL_2=28
> 
> GRAY_INK_3=LLK
> GRAY_VAL_3=9
> 
> GRAY_INK_4=
> GRAY_VAL_4=
> 
> GRAY_HIGHLIGHT=6
> GRAY_SHADOW=6
> 
> GRAY_GAMMA=1
> GRAY_CURVE=
> 
> #
> # Toner Partition Information
> #
> N_OF_TONER_PARTS=2
> TONER_INK_1=C
> TONER_VAL_1=100
> TONER_INK_2=LC
> TONER_VAL_2=30
> 
> TONER_HIGHLIGHT=6
> TONER_SHADOW=6
> 
> TONER_GAMMA=1
> TONER_CURVE="0;0 25;23 50;41 63;55 75;70 85;85 100;100"
> 
> N_OF_TONER_2_PARTS=2
> TONER_2_INK_1=M
> TONER_2_VAL_1=100
> TONER_2_INK_2=LM
> TONER_2_VAL_2=25
> 
> TONER_2_HIGHLIGHT=6
> TONER_2_SHADOW=6
> 
> TONER_2_GAMMA=1
> TONER_2_CURVE="0;0 23;20 50;45 63;60 75;77 100;100"
>

I managed to get rid of the tint.
Still need to improve the Dmax. I changed the Boost_K value to 60. But that didn't change anything. 1,54 is all I can measure...
I could tweak the ABW settings to get 1,60.

Perhaps my crossover values are worng? But then again I have no idea whether these values do influence the Dmax.

Any thoughts?

what is the max dmax for K only 100%?
It may not be @ the 100% patch.

you need to know this in order to know what your reasonable dmax goal is?

Mike

On 7 March 2010 14:01, siiaam <s-i-a-m@...> wrote:

>
>
> I managed to get rid of the tint.
> Still need to improve the Dmax. I changed the Boost_K value to 60. But that
> didn't change anything. 1,54 is all I can measure...
> I could tweak the ABW settings to get 1,60.
>
> Perhaps my crossover values are worng? But then again I have no idea
> whether these values do influence the Dmax.
>
> Any thoughts?
>
>  
>


[Non-text portions of this message have been removed]

Michael King <drmrking@...> wrote:
>
> what is the max dmax for K only 100%?
> It may not be @ the 100% patch.
> 

With a 1400 and Eboni Lab L = 16.1 (about d. 1.67) is what I see in my database.

Paul
www.PaulRoark.com

Michael King <drmrking@...> wrote:
>
> what is the max dmax for K only 100%?
> It may not be @ the 100% patch.


With a 2200, the Epson driver and Eboni Lab L=16.28.

Paul
www.PaulRoark.com

From the ink seperation target:

Dmax: 1,56
L: 18,90

Does that mean that it won't get further than that?

Stephan

--- In QuadtoneRIP@yahoogroups.com, Michael King <drmrking@...> wrote:

>
> what is the max dmax for K only 100%?
> It may not be @ the 100% patch.
> 
> you need to know this in order to know what your reasonable dmax goal is?
> 
> Mike
> 
> On 7 March 2010 14:01, siiaam <s-i-a-m@...> wrote:
> 
> >
> >
> > I managed to get rid of the tint.
> > Still need to improve the Dmax. I changed the Boost_K value to 60. But that
> > didn't change anything. 1,54 is all I can measure...
> > I could tweak the ABW settings to get 1,60.
> >
> > Perhaps my crossover values are worng? But then again I have no idea
> > whether these values do influence the Dmax.
> >
> > Any thoughts?
> >
> >  
> >
> 
> 
> [Non-text portions of this message have been removed]
>

Yep... adding more inks reduces the dmax doesn't increase it.
So max dmax is, max dmax for darkest ink by itself.

Mike

On 7 March 2010 18:36, siiaam <s-i-a-m@...> wrote:

>
>
> From the ink seperation target:
>
> Dmax: 1,56
> L: 18,90
>
> Does that mean that it won't get further than that?
>
> Stephan
>
>
> --- In QuadtoneRIP@yahoogroups.com <QuadtoneRIP%40yahoogroups.com>,
> Michael King <drmrking@...> wrote:
> >
> > what is the max dmax for K only 100%?
> > It may not be @ the 100% patch.
> >
> > you need to know this in order to know what your reasonable dmax goal is?
> >
> > Mike
> >
> > On 7 March 2010 14:01, siiaam <s-i-a-m@...> wrote:
> >
> > >
> > >
> > > I managed to get rid of the tint.
> > > Still need to improve the Dmax. I changed the Boost_K value to 60. But
> that
> > > didn't change anything. 1,54 is all I can measure...
> > > I could tweak the ABW settings to get 1,60.
> > >
> > > Perhaps my crossover values are worng? But then again I have no idea
> > > whether these values do influence the Dmax.
> > >
> > > Any thoughts?
> > >
> > >
> > >
> >
> >
> > [Non-text portions of this message have been removed]
> >
>
>  
>


[Non-text portions of this message have been removed]

Thanks. But how is it possible to achieve 1,60 with ABW?


--- In QuadtoneRIP@yahoogroups.com, Michael King <drmrking@...> wrote:

>
> Yep... adding more inks reduces the dmax doesn't increase it.
> So max dmax is, max dmax for darkest ink by itself.
> 
> Mike

It maybe that there is an ink value higher than the dmax you are measuring
but lower than the next target value? Also a single ink patch is not
reliable you probably need to print the target 5 times on different
locations on  a sheet of paper and read it. 1.54 and 1.6 are not very far
apart and definitely well within the paper coating /batch variability. Did
you get 1.6 with ABW with the same batch of paper?

Mike

On 7 March 2010 18:57, siiaam <s-i-a-m@...> wrote:

>
>
> Thanks. But how is it possible to achieve 1,60 with ABW?
>
>
> --- In QuadtoneRIP@yahoogroups.com <QuadtoneRIP%40yahoogroups.com>,
> Michael King <drmrking@...> wrote:
> >
> > Yep... adding more inks reduces the dmax doesn't increase it.
> > So max dmax is, max dmax for darkest ink by itself.
> >
> > Mike
>
>  
>


[Non-text portions of this message have been removed]

1,54 is the highest value. I am measuring 1,6 on the same sheet of paper... You are probably right about the multiple target prints.

Well, I guess I'll stick to ABW and built a correction curve from that target. Learnt some new things about QTR, though.
Thanks anyway.

Stephan

--- In QuadtoneRIP@yahoogroups.com, Michael King <drmrking@...> wrote:

>
> It maybe that there is an ink value higher than the dmax you are measuring
> but lower than the next target value? Also a single ink patch is not
> reliable you probably need to print the target 5 times on different
> locations on  a sheet of paper and read it. 1.54 and 1.6 are not very far
> apart and definitely well within the paper coating /batch variability. Did
> you get 1.6 with ABW with the same batch of paper?
> 
> Mike
> 
> On 7 March 2010 18:57, siiaam <s-i-a-m@...> wrote:
> 
> >
> >
> > Thanks. But how is it possible to achieve 1,60 with ABW?