QTR-Quadtone RIP

HELLO GROUP,

I have had some very good results with QTR since I purchased it
approximately 18 months ago. However, I have also experienced some
problems along the way. On occasion I have noticed what I can only
describe as a sort of "Splotching" effect in some prints. What this
amounts to is a rather irregular pattern of increased density. Almost
as if I were to take a brush and paint in more density in a haphazard
way. Of course this effect will always render the print unusable. The
other part of this anomaly is that when I do a reprint, it will
sometimes not appear at all, or it will manifest itself in a
completely different area of the image. Yesterday I encountered a
problem I haven't noticed for a while, although it has been there on
occasion. I was trying to print an 11x14 Warm Sepia. Down one side and
not as noticeably on the other side was what I would describe as a
sort of banding. The "bands", again, were all of a plus density
nature, very diffused, and approximately 1/8th of an inch in width. I
did 2 prints with basically the same results. I then printed the image
through the Epson driver and had no problem at all. Of course I
couldn't obtain the effect was trying to achieve with QTR, but at
least I did finally get a print.  

Let me clarify one thing. These problems are happening in what seems
to be a totally random way. Both while trying to achieve a neutral
print and while utilizing one or more of "color" curves provided. And
again, as I mentioned previously, the second and third prints from the
same file may or may not show the problem. I am using a 7600 with MK
and I always make sure the nozzles are clear before printing. All of
these prints are done on Epson Enhanced Matte Paper. I have no problem
with the native Epson driver, either when printing color or a neutral
image. I very much like the possibilities provided with QTR and the
neutrality of the images, but if I can't find a solution to this
situation, I may have to take it out of my workflow. I DO NOT want to
do that, so I hope someone will be able to offer a bit of advice
concerning this problem.

Thank you,
Gary

Gary,

If this is a density shift with feathered edges and is found ONLY in 
the solid black areas, then it is a common problem with the gimp 
driver which QTR utilizes.  I have experienced this a number of 
times.  Adding about 2% noise to the image tends to eliminate this 
feathered banding.  I usually duplicate the final image and run th 
noise filter through a blurred mask to limit it to the black areas.  
The blur helps avoid any lines of demarcation so it isn't obvious.  I 
haven't tested it, but I have heard that adding just a little of a 
2nd ink to pure black end of the profile can also eliminate the 
effect.

I have recently been building 2880 dpi profiles and haven't yet 
noticed this effect at the higher dpi.  Not sure if it will surface 
or not.  

If you are seeing this problem in areas other than just the pure 
black regions, it probably is a different issue, which I have not 
experienced.  

Lou

--- In QuadtoneRIP@yahoogroups.com, "photog0946" <gnickzone@...> 
wrote:
>
> HELLO GROUP,
> 
> I have had some very good results with QTR since I purchased it
> approximately 18 months ago. However, I have also experienced some
> problems along the way. On occasion I have noticed what I can only
> describe as a sort of "Splotching" effect in some prints. What this
> amounts to is a rather irregular pattern of increased density. 
Almost
> as if I were to take a brush and paint in more density in a 
haphazard
> way. Of course this effect will always render the print unusable. 
The
> other part of this anomaly is that when I do a reprint, it will
> sometimes not appear at all, or it will manifest itself in a
> completely different area of the image. Yesterday I encountered a
> problem I haven't noticed for a while, although it has been there on
> occasion. I was trying to print an 11x14 Warm Sepia. Down one side 
and
> not as noticeably on the other side was what I would describe as a
> sort of banding. The "bands", again, were all of a plus density
> nature, very diffused, and approximately 1/8th of an inch in width. 
I
> did 2 prints with basically the same results. I then printed the 
image
> through the Epson driver and had no problem at all. Of course I
> couldn't obtain the effect was trying to achieve with QTR, but at
> least I did finally get a print.  
> 
> Let me clarify one thing. These problems are happening in what seems
> to be a totally random way. Both while trying to achieve a neutral
> print and while utilizing one or more of "color" curves provided. 
And
> again, as I mentioned previously, the second and third prints from 
the
> same file may or may not show the problem. I am using a 7600 with MK
> and I always make sure the nozzles are clear before printing. All of
> these prints are done on Epson Enhanced Matte Paper. I have no 
problem
> with the native Epson driver, either when printing color or a 
neutral
> image. I very much like the possibilities provided with QTR and the
> neutrality of the images, but if I can't find a solution to this
> situation, I may have to take it out of my workflow. I DO NOT want 
to

> do that, so I hope someone will be able to offer a bit of advice
> concerning this problem.
> 
> Thank you,
> Gary
>

Thanks Louis,

I have previously used a small bit of noise in solid areas of color
images to reduce banding, so I am somewhat familiar with the process.
However, to my GREAT embarrassment, I must admit that the problem I
have encountered might have been due to an oversight on my part. I
went back into the RIP to print a test with 2880 instead of 1440. It
was then that I noticed I had been using the "Faster" setting in the
Speed section. I always save presets for the most used profiles, and I
had apparently overlooked that section when doing so. I have since
reprinted the image I was having difficulty with yesterday, except
with the "Better" setting and still at 1440. The image printed without
a problem this time, and I'm hoping this will also fix the problem I
have had with neutral prints on occasion. Another lesson learned! Will
it never end?

My next test will be at 2880 with the same image to determine whether
or not the deeper areas of the print are carrying slightly less noise. 

Thanks again Louis. Had it not been for your email, I might not have
noticed my mistake.

Gary

--- In QuadtoneRIP@yahoogroups.com, "photog0946" <gnickzone@...> wrote:

> My next test will be at 2880 with the same image to determine whether

Hi there, Does printing at 2880 in QTR make a material difference?

regards

Alistiar Owens
owens@...

I think it does.  I feel I am getting better results using 2800 dpi, 
unidirectional (better quality) and ordered dithering.  Better Dmax and 
finer detail.  It is worth noting that if you print at 2880 for a 
profile that was originally designed for 1440, your prints will be 
darker.  So you need to either adjust the profile, or use the sliders 
in QTR to reduce the density when printing.  I prefer to rebuild the 
profiles, so I haven't played much with the sliders.

Lou

--- In QuadtoneRIP@yahoogroups.com, "alistair_owens" <owens@...> wrote:
>
> --- In QuadtoneRIP@yahoogroups.com, "photog0946" <gnickzone@> wrote:
> 
> > My next test will be at 2880 with the same image to determine 
whether

> 
> Hi there, Does printing at 2880 in QTR make a material difference?
> 
> regards
> 
> Alistiar Owens
> owens@...
>

It may depend on your situation, but in mine (Epson 2100, UT3D, Photo 
Rag) it does make a difference. Not earth-moving, I'm happy with my 
1440 prints as well, but 2880 is just that bit smoother. Some report 
also tiny microbanding issues at 1440 disappearing at 2880. Imho you 
MUST rebuild your profiles for 2880. Ink load is so much different for 
the two resolutions.

Joost
 

--- In QuadtoneRIP@yahoogroups.com, "alistair_owens" <owens@...> wrote:
>
> --- In QuadtoneRIP@yahoogroups.com, "photog0946" <gnickzone@> wrote:
> 
> > My next test will be at 2880 with the same image to determine 
whether

> 
> Hi there, Does printing at 2880 in QTR make a material difference?
> 
> regards
> 
> Alistiar Owens
> owens@...
>