QTR-Quadtone RIP

Hi everybody,

while trying to print at 2880dpi I've know realised that all my images 
are consistently stretched vertically by about a factor of 2, even
the initial ink pattern page in calibration mode and the 21step test 
prints. Is this a known issue or may I have done something wrong? I 
choose 2880 because the initial ink pattern page looked very smooth 
when compared to the 1440dpi printout (even if it was stretched)

regards, Jamie

--- In QuadtoneRIP@yahoogroups.com, "Jamie" <icucjamie@h...> wrote:
> Hi everybody,
> 
> while trying to print at 2880dpi I've know realised that all my images 
> are consistently stretched vertically by about a factor of 2, even
> the initial ink pattern page in calibration mode and the 21step test 
> prints. Is this a known issue or may I have done something wrong? I 
> choose 2880 because the initial ink pattern page looked very smooth 
> when compared to the 1440dpi printout (even if it was stretched)
> 
> regards, Jamie

Jamie,

You don't mention which printer or what QTR version but I'll guess that you
are using a 1280 at 2880x720 and the code is thinking 2880x1440.  Anyway the
lastest version 2.3 fixed some high dpi problems and I think this is one of them.
Since I don't have a 1280 I wasn't able to test it.  See and download:

http://homepage.mac.com/royharrington/FileSharing3.html

Let me know if this solves the problem.  Also you should note that the profiles
are tuned for 1440 so they may require some Ink Limit Adjustment when printing.

Roy

--- In QuadtoneRIP@yahoogroups.com, "John Moody" <moodymz3@y...> wrote:
> Can profiles affect dither patterns in any large way?  I'm talking about
> tweaks to one profile, not profiles for different papers, inks, etc.
> Soon, I will be spending significant time creating profiles for a modified
> UT7 set, and if there is a way to improve the dither pattern I would like to
> incorporate that.
> 
> I'm currently printing with 2200 UC inks on EEM.
> Specifically, I see sparse dark dots in the ¾ tones that I do not see when
> printing through the Epson driver.  By sparse, I mean there are maybe 10
> dots between the dark dots.  Printing modes are,1440 super on QTR better
> speed, 1440 no-high-speed on Epson driver.  QTR is far superior in every
> way, other than dither patterns.  I would like to find a way to do better.
> 
> Best regards,
> John Moody

Hi John,

The way dithering is done is pretty much fixed -- unaffected by the profiles.
However the idea behind partitioning multiple gray inks is to hide the dithering
so you don't see it.  So in this sense the profiles can make a difference in the
visibility of the dots and dithering.

I'm guessing what you are seeing with the dark dots in the 3/4 tones is simply
the transition from light-black ink to black ink.  It has to happen sometime.
The idea of partitioning is to introduce black only when the light-black is close
to full so you see K against LK rather than K against white paper.  Does this sound
like what you are seeing?  If the black dots are sparcely separated that's the idea
of dithering.  

When you print with the Epson driver more inks are used so the hiding of dots is
better but of course this is what introduces metamerism.

When you go to UT7 things are a bit better since there are 3 grays rather than 2.
Quad systems are very smooth and the ultimate is Cone's new K7 with 7 grays.

Roy

--- In QuadtoneRIP@yahoogroups.com, "John Moody" <moodymz3@y...> wrote:
> Roy,
> Is gimp-print now called Gutenprint?
> It looks like lots of work have been put into the 5.0.0 beta release for
> improved, and additional dither algorithms.  When might this show up in QTR?
> 
> Are there any early integration tests with the 5.0 releases that look useful
> for QTR users?
> 
> Best regards,
> John Moody

Yes, gimp-print has been renamed Gutenprint.  I've kind of kept up with what they
are doing but haven't actually used any of the newer stuff.  Most of what they have
added is not relevant.  I've spent more time with accurate calibration than they have.

Rather than constantly chasing a ever moving target I feel the best strategy is to 
stick with a known quantity to make the most stable product.

Roy

--- In QuadtoneRIP@yahoogroups.com, "Roy Harrington" <roy@h...> 
wrote:
> --- In QuadtoneRIP@yahoogroups.com, "Jamie" <icucjamie@h...> wrote:
> > Hi everybody,
> > 
> > while trying to print at 2880dpi I've know realised that all my 
images 
> > are consistently stretched vertically by about a factor of 2, 
even
> > the initial ink pattern page in calibration mode and the 21step 
test 
> > prints. Is this a known issue or may I have done something 
wrong? I 
> > choose 2880 because the initial ink pattern page looked very 
smooth 
> > when compared to the 1440dpi printout (even if it was stretched)
> > 
> > regards, Jamie
> 
> Jamie,
> 
> You don't mention which printer or what QTR version but I'll guess 
that you
> are using a 1280 at 2880x720 and the code is thinking 2880x1440.  
Anyway the
> lastest version 2.3 fixed some high dpi problems and I think this 
is one of them.
> Since I don't have a 1280 I wasn't able to test it.  See and 
download:
> 
> http://homepage.mac.com/royharrington/FileSharing3.html
> 
> Let me know if this solves the problem.  Also you should note that 
the profiles
> are tuned for 1440 so they may require some Ink Limit Adjustment 
when printing.
> 
> Roy

thanks Roy for the quick reply and advice, and of course your 
excellent piece of software. I'm using a 1290 with version 2.2, but 
following the update to version 2.3 my problem is solved. I'm having 
a try at producing some curves for my own printer/inksetup (Permajet 
MonoChrome Pro inkset) at 2880dpi, using an X-rite Pulse spectro, 
and some existing curves as templates. So far so good, my first ink 
pattern page resulted in a basic ink limit of 60%. Do you know if 
Permajet MonoChrome Pro inkset is similar to UT2 inkset; I hope so 
because that would mean I could use the existing curves which are 
available?