Digital BW, The Print

I've recently installed Roy Harrington's QuadTone Rip 2.0

Running set-up tests with..
 PizeoTone selenium inks
 Epson Matt Heavyweight [A3]
 Quad Tone Rip 2.0


WOW - The results are stunning!,  However the photographer whose work I've
been printing commented on what appeared to be slight 'tonal' banding
running down the length of the print. Bands are about 30-35mm apart.

I checked prints made from the same file printed using the Cone driver - no
banding. 

While we were looking at the print to see what it was I Turned the print
over and we could see the same banding pattern on the back of the print!  On
closer inspection we saw the print paper (Epson MHW) had *very* small but
regularly spaced 30-35mm wide corrugations running down the entire length of
the print. These corrugations are easier to feel than to see directly.

The corrugations are confined to just the printed area.
They are also slightly deeper where the ink lay-down is heavier.
Print paper is definitely flat before it's printed.
I have checked all the other prints made with QTR 2 and found they too have
corrugated the paper in the print area.

We found that the appearance of 'tonal banding' of the print disappears when
the print paper is bent into a strong curve in such a way as to flatten the
corrugations.


My guess is there something about the way ink is being laid down by QTR 2
that¹s causing the paper to swell in a regular pattern.


Regards
Peter Miles






##############################


Message: 22
   Date: Sun, 02 Nov 2003 03:01:42 -0000

   From: "candlefarmer" <yahoo@robeybaur.org>
Subject: Vertical banding with QTR 2

>I've recently started experimenting with the Harrington Quadtone RIP v2. I'm
using the latest beta on an Epson 2200 with the standard Epson inks. Generally
the results are outstanding but I continue to have one show-stopper problem:
vertical banding in dark areas of the print. This seems to be specific to the
QTR RIP - the same image printed using the epson driver shows no such banding.

>It seems to be independent of resolution. I typically use 720x720 but see it in
higher resolutions also.

>I originally thought that the banding was due to excessive ink in dark areas. I
tried lowering the ink limit but the banding remains.

>I've posted an example here:

>http://home.comcast.net/~baur/banding.html

>Is this something others have seen? Any help in taming this would be
appreciated. (I'm trying to get a couple of things printed for a show and this
is driving me batty.)

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Peter Miles <P.Miles@m=
...> 
wrote:
> I've recently installed Roy Harrington's QuadTone Rip 2.0
> 
> Running set-up tests with..
>  PizeoTone selenium inks
>  Epson Matt Heavyweight [A3]
>  Quad Tone Rip 2.0
> 
> 
> WOW - The results are stunning!,  However the photographer whose work I'v=
e
> been printing commented on what appeared to be slight 'tonal' banding
> running down the length of the print. Bands are about 30-35mm apart.
> 
> I checked prints made from the same file printed using the Cone driver - =
no
> banding. 
> 
> While we were looking at the print to see what it was I Turned the print
> over and we could see the same banding pattern on the back of the print! =
 On
> closer inspection we saw the print paper (Epson MHW) had *very* small but=

> regularly spaced 30-35mm wide corrugations running down the entire length=
 of
> the print. These corrugations are easier to feel than to see directly.

I'm having a hard time understanding what you are actually seeing.   So
the pattern goes down the paper not along the head direction?  I'm also
not sure about "very small" and "30-35mm"  which sounds very large.
Is it possible to see it with a scanner, so you could show it?

How you tried other kinds of paper?  I don't think HWM is recommended
for pigment inks -- maybe there's just too much ink for the paper to absorb=
.
Other alternatives are to try different "Image Types" and "Dither Algorithm=
s",
you may get different results.

Roy

> 
> The corrugations are confined to just the printed area.
> They are also slightly deeper where the ink lay-down is heavier.
> Print paper is definitely flat before it's printed.
> I have checked all the other prints made with QTR 2 and found they too ha=
ve
> corrugated the paper in the print area.
> 
> We found that the appearance of 'tonal banding' of the print disappears w=
hen
> the print paper is bent into a strong curve in such a way as to flatten t=
he
> corrugations.
> 
> 
> My guess is there something about the way ink is being laid down by QTR 2=

> that¹s causing the paper to swell in a regular pattern.
> 
> 
> Regards
> Peter Miles
> 
> 
> 
> 
> 
> 
> ##############################
> 
> 
> Message: 22
>    Date: Sun, 02 Nov 2003 03:01:42 -0000
>    From: "candlefarmer" <yahoo@r...>
> Subject: Vertical banding with QTR 2
> 
> >I've recently started experimenting with the Harrington Quadtone RIP v2.=
 I'm
> using the latest beta on an Epson 2200 with the standard Epson inks. Gene=
rally
> the results are outstanding but I continue to have one show-stopper probl=
em:
> vertical banding in dark areas of the print. This seems to be specific to=
 the
> QTR RIP - the same image printed using the epson driver shows no such ban=
ding.
> 
> >It seems to be independent of resolution. I typically use 720x720 but se=
e it in
> higher resolutions also.
> 
> >I originally thought that the banding was due to excessive ink in dark a=
reas. I
> tried lowering the ink limit but the banding remains.
> 
> >I've posted an example here:
> 
> >http://home.comcast.net/~baur/banding.html
> 
> >Is this something others have seen? Any help in taming this would be
> appreciated. (I'm trying to get a couple of things printed for a show and=
 this
> is driving me batty.)

At 15:42 +1300 10.11.2003, Peter Miles wrote:
*******************************************

>While we were looking at the print to see what it was I Turned the print
>over and we could see the same banding pattern on the back of the print!  On
>closer inspection we saw the print paper (Epson MHW) had *very* small but
>regularly spaced 30-35mm wide corrugations running down the entire length of
>the print. These corrugations are easier to feel than to see directly.

Which printer do you use?

if 7600/9600 - the Epson MHW is quite thin paper and if you use full 
suction on printer the ink on part of paper which is in contact with 
suction holes may penetrate more into paper. If you use 7600/9600 try 
reduce the suction - release the lever and press the Paper Feed Down 
button. Close the lever.

Martin
--

Peter Miles wrote...

> I've recently installed Roy Harrington's QuadTone Rip 2.0
> 
> Running set-up tests with..
>  PizeoTone selenium inks
>  Epson Matt Heavyweight [A3]
>  Quad Tone Rip 2.0
> 
> 
> WOW - The results are stunning!,  However the photographer
> whose work I've been printing commented on what appeared to be slight
> 'tonal' banding running down the length of the print. Bands are about
> 30-35mm apart.
> 
> I checked prints made from the same file printed using the Cone driver - no
> banding. 
> 
> While we were looking at the print to see what it was I Turned the print
> over and we could see the same banding pattern on the back of the print! On
> closer inspection we saw the print paper (Epson MHW) had *very* small but
> regularly spaced 30-35mm wide corrugations running down the entire length of
> the print. These corrugations are easier to feel than to see directly.
>  



Roy Harrington wrote...

> I'm having a hard time understanding what you are actually seeing.
> So the pattern goes down the paper not along the head direction?

Yes, that is correct.


> I'm also not sure about "very small" and "30-35mm"  which sounds very large.

Sorry I was a bit vague. The spacing between corrugations is 30 - 35mm but
the depth of corrugations is very small.

This means that the print surface is not quite flat. The varying print
viewing angle seems to cause very slight variations in the appearance of the
print tone values. On the print, this slight variation becomes apparent in
areas of very flat print tone such as cloudless sky.


> Is it possible to see it with a scanner, so you could show it?
> How you tried other kinds of paper?  I don't think HWM is recommended

We found Epson Archival Matte paper ripples to a lesser extent than Epson
MHW 


> for pigment inks -- maybe there's just too much ink for the paper to absorb.

I pretty sure this is the real problem.
We have run more tests last night and some more tests this morning.
The regular pattern of ripples correspond with the gaps between the top
pinch rollers of the 1160. I think the paper is swelling with the ink and
the only place the print can buckle is between the gaps between the top
pinch rollers, This seems to be the cause of the regularity of the ripple
pattern.

Is there something in  my "quadtone curve descriptor file" That would cause
excessive ink loading?

<Snip-ink limits>
LIMIT_K=85
BOOST_K=100
LIMIT_C=100
LIMIT_M=95
LIMIT_Y=95

<Snip-Gray Partition Information>
N_OF_GRAY_PARTS=4
GRAY_INK_1=K
GRAY_VAL_1=100

GRAY_INK_2=C
GRAY_VAL_2=30

GRAY_INK_3=M
GRAY_VAL_3=5.05

GRAY_INK_4=Y
GRAY_VAL_4=2.86

GRAY_HIGHLIGHT=11
GRAY_SHADOW=11

GRAY_OVERLAP=50
GRAY_GAMMA=1
GRAY_CURVE=



> Other alternatives are to try different "Image Types" and "Dither Algorithms",
> you may get different results.

We found printing faster (1440x720 bidirectional) reduced the depth of the
ripples somewhat [without any change in print quality].
> 
> Roy

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Peter Miles <P.Miles@m...> 
wrote:
> 
> 
>  Peter Miles wrote...
> 
> > I've recently installed Roy Harrington's QuadTone Rip 2.0
> > 
> > Running set-up tests with..
> >  PizeoTone selenium inks
> >  Epson Matt Heavyweight [A3]
> >  Quad Tone Rip 2.0
> > 
> > 
> > WOW - The results are stunning!,  However the photographer
> > whose work I've been printing commented on what appeared to be slight
> > 'tonal' banding running down the length of the print. Bands are about
> > 30-35mm apart.
> > 
> > I checked prints made from the same file printed using the Cone driver - no
> > banding. 
> > 
> > While we were looking at the print to see what it was I Turned the print
> > over and we could see the same banding pattern on the back of the print! On
> > closer inspection we saw the print paper (Epson MHW) had *very* small but
> > regularly spaced 30-35mm wide corrugations running down the entire length of
> > the print. These corrugations are easier to feel than to see directly.
> >  
> 
> 
> 
> Roy Harrington wrote...
> 
> > I'm having a hard time understanding what you are actually seeing.
> > So the pattern goes down the paper not along the head direction?
> 
> Yes, that is correct.
> 
> 
> > I'm also not sure about "very small" and "30-35mm"  which sounds very large.
> 
> Sorry I was a bit vague. The spacing between corrugations is 30 - 35mm but
> the depth of corrugations is very small.
> 
> This means that the print surface is not quite flat. The varying print
> viewing angle seems to cause very slight variations in the appearance of the
> print tone values. On the print, this slight variation becomes apparent in
> areas of very flat print tone such as cloudless sky.
> 
> 
> > Is it possible to see it with a scanner, so you could show it?
> > How you tried other kinds of paper?  I don't think HWM is recommended
> 
> We found Epson Archival Matte paper ripples to a lesser extent than Epson
> MHW 
> 
> 
> > for pigment inks -- maybe there's just too much ink for the paper to absorb.
> 
> I pretty sure this is the real problem.
> We have run more tests last night and some more tests this morning.
> The regular pattern of ripples correspond with the gaps between the top
> pinch rollers of the 1160. I think the paper is swelling with the ink and
> the only place the print can buckle is between the gaps between the top
> pinch rollers, This seems to be the cause of the regularity of the ripple
> pattern.
> 
> Is there something in  my "quadtone curve descriptor file" That would cause
> excessive ink loading?
> 
> <Snip-ink limits>
> LIMIT_K=85
> BOOST_K=100
> LIMIT_C=100
> LIMIT_M=95
> LIMIT_Y=95
> 
> <Snip-Gray Partition Information>
> N_OF_GRAY_PARTS=4
> GRAY_INK_1=K
> GRAY_VAL_1=100
> 
> GRAY_INK_2=C
> GRAY_VAL_2=30
> 
> GRAY_INK_3=M
> GRAY_VAL_3=5.05
> 
> GRAY_INK_4=Y
> GRAY_VAL_4=2.86
> 
> GRAY_HIGHLIGHT=11
> GRAY_SHADOW=11
> 
> GRAY_OVERLAP=50
> GRAY_GAMMA=1
> GRAY_CURVE=
> 
> 
> 
> > Other alternatives are to try different "Image Types" and "Dither Algorithms",
> > you may get different results.
> 
> We found printing faster (1440x720 bidirectional) reduced the depth of the
> ripples somewhat [without any change in print quality].
> > 
> > Roy

Peter,

Looking at your parameters here I'd say you are really over saturating
the paper. I have an 1160 -- although it's a VM ink set not a quad set
such as piezo.   First your ink limits seem very high.  I use limit=70 with
the boost_k up to 90 or 100.  So K,C,M,Y = 70 and BOOST_K=100.
Second the GRAY_OVERLAP is very high -- basically meaning 150% of the
ink (based on their ink limit).   I use GRAY_OVERLAP=0 now.  Once
you change these values you won't have such huge dot gain and the
GRAY_VAL numbers will need to change.   You should do the ink calibration
again with these lower ink limits and I'd expect instead of 30, 5, 2.8  they
will be more like 45, 10, 5.  

Roy

HI Roy


Peter miles wrote: <big snip>
>> Is there something in  my "quadtone curve descriptor file" That would cause
>> excessive ink loading?
>>
 
<Roy Harrington wrote>
> Peter,
> 
> Looking at your parameters here I'd say you are really over saturating
> the paper. I have an 1160 -- although it's a VM ink set not a quad set
> such as piezo.   First your ink limits seem very high.  I use limit=70 with
> the boost_k up to 90 or 100.  So K,C,M,Y = 70 and BOOST_K=100.
> Second the GRAY_OVERLAP is very high -- basically meaning 150% of the
> ink (based on their ink limit).   I use GRAY_OVERLAP=0 now.  Once
> you change these values you won't have such huge dot gain and the
> GRAY_VAL numbers will need to change.   You should do the ink calibration
> again with these lower ink limits and I'd expect instead of 30, 5, 2.8  they
> will be more like 45, 10, 5.
> 
> Roy


Thanks for that. I've just finished testing two new ink description
settings, one with the 0 GRAY_OVERLAP but the old high ink limits and one
with 0 GRAY_OVERLAP with 70% ink limits.
No sign of paper rippling at all with the 70%, 0 GRAY_OVERLAP setting
[D-max dropped from 1.66 to 1.62].

Much Thanks Roy for for all your help.

Kind Regards
Peter Miles