Digital BW, The Print

Hi JM,

I think I understand a little better now. At this point I can only
speculate as to what may be the source of this banding. 

Each profile supplied with either QTR or IJC/OPM, or Imageprint for
that matter, are designed from a particular printer and media, and
ink. As we know all Epsons of a particular model are not the same.
What I'm leading to is the ink limits and densities may vary from
printer to printer. This may lead to a rare but very possible scenario
in which you get an extremely narrow overlap between the light and
medium gray inks. 

One ink starts to fade out before the other gains in strength causing
a lack of a smooth transition in tones. I can easily see that the
transition from medium to light gray is the most vulnerable to
variation in printhead characteristic. So I think it just so happens
that the canned profile that came with QTR doesn't work properly in
your situation. Again I'm assuming that missing or deflecting nozzles
are not involved.

I think it is a good idea to create a profile for the paper/inkset
that you are having problems with. You can quickly create one within
just half an hour just to prove whether the problem is with QTR or not.

--nick

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "joemulligan_68"
<joemulligan_68@y...> wrote:
> 
> Hi Nick,
> 
> Thank you for your feedback.  I simply use the curves that are 
> loaded with the Windows version of QTR/QTRgui.  Yesterday, I printed 
> some images of rock formations with sky and clouds above.  What I 
> notice is that the highlights show some sort of "dither banding" 
> while with the shadows (rocks) this banding or dithering is 
> camouflaged.  It is highly obvious in high key images.  This banding 
> always runs parallel to the print head.  I have ruled out paper 
> alignment and nozzle problems because this problem only happens with 
> QTR.  It sometimes happens on some images with Imageprint but I have 
> never seen it printing the same files with IJC/OPM nor the standard 
> Epson driver.   
> 
> I just want to know if anyone has the same problem.  I can try and 
> relinearize as you suggest but this problem happens with every curve 
> that is loaded with QTR.
> 
> Any other thoughts?
> 
> JM
> -- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Nick H. Nugent" 
> <nghin@p...> wrote:
> > 
> > Hi JM,
> > 
> > I did a slew of profiles for multiple papers and inksets and 
> actually 
> > got one that gave serious posterization in the bright skin tone 
> > areas. All I did was rescanned the target, entered linearization 
> > data, and regenerated the curve and the problem went away.
> > 
> > I have no idea that might have caused the problem, but with the 
> > problem profile I noticed a sharp dip just about where I noticed 
> the 
> > banding or posterization. This could not have been caused by my 
> > reading an incorrect target because the dip is very sharp.
> > 
> > It could have been the data I entered manually and made a mistake 
> > somewhere. For the rest of the profiles data are entered using a 
> more 
> > automated process to reduce possibility for errors.
> > 
> > I hope this help,
> > --nick
> > 
> > --- In 
> DigitalBlackandWhiteThePrint@yahoogroups.com, "joemulligan_68" 
> > <joemulligan_68@y...> wrote:
> > > 
> > > ... I also use 1440 super and better as well as Ordered Dither.  
> No 
> > > matter what settings I use QTR always bands. I am wondering if 
> what 
> > > I am mistaking for banding is actually visible dithering but I 
> > > tried adding 2% noise and 5% and this problem is still evident.  
> I 
> > > am certain this is not a nozzle problem like I mentioned in my 
> > > previous post...