Digital BW, The Print

----- Original Message ----- 
From: "Roy Harrington" <roy@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Sunday, November 02, 2003 8:16 AM
Subject: Re: [Digital BW] Vertical banding with QTR 2


> > On Saturday, November 1, 2003, at 10:01  PM, candlefarmer
wrote:
> >
> > > 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.)

On the colorsync list was a discussion about vertical banding as
a result of less ink used in linearised RIPs if compared to the
Epson driver's use of ink. By that lower quantity of ink the
imperfections in paper and papercoatings are more prone to show.
I have my doubts about that explanation but you may try to turn
the paper 90 degrees to see whether there's a relation to the
papermaking process. If the banding is very regular in frequency
then it is unlikely that it has anything to do with the
papermaking. And your examples are more like that. Have you
checked the imagefile (brighten + contrast) whether it shows
similar banding as a result of scanning for example ?  It may be
that QTR2 reveals it and the Epson driver doesn't.

Ernst