QTR-Quadtone RIP

I'm getting slight banding especially in the both ends on a A6 
landscape print on epson matte HW. I have tried a lot of combinations 
including increasing shadow darkness and gamma with no result. I print 
in 2800dpi as 1440dpi results in even more banding. Same image printed 
in Photoshop at the same time has absolutely no banding, so it must be 
related to the rip. On semigloss I had the same problme plus the ink 
never dries, so that's why I now go for the matte paper.
Any suggestion highly appreciated, as this RIP seems to be able to get 
rid of the colorcast produced by photoshop on the 1800.
thanks in advance,
Peter Oksen,
Denmark

Hi Peter,

Banding tends to be a problem on the R800 & R1800 because there is
only one-black ink.  The more inks used the more likely the physical jet
variations are covered up.  That's why the Epson driver looks better for
banding but then has the problems of color casts, etc.
Its the only printer that I'd always recommend 2880dpi.  To add to the
problem the beginning and end of a sheet require using a less optimal
weaving.  Leaving bigger borders is the easiest way around this.

Roy

On Thursday, June 15, 2006, at 02:33  PM, oksen wrote:

> I'm getting slight banding especially in the both ends on a A6
> landscape print on epson matte HW. I have tried a lot of combinations
> including increasing shadow darkness and gamma with no result. I print
> in 2800dpi as 1440dpi results in even more banding. Same image printed
> in Photoshop at the same time has absolutely no banding, so it must be
> related to the rip. On semigloss I had the same problme plus the ink
> never dries, so that's why I now go for the matte paper.
> Any suggestion highly appreciated, as this RIP seems to be able to get
> rid of the colorcast produced by photoshop on the 1800.
> thanks in advance,
> Peter Oksen,
> Denmark
>
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>
> Yahoo! Groups Links
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-
Roy Harrington
roy@...
Black & White Photo Gallery
http://www.harrington.com

--- In QuadtoneRIP@yahoogroups.com, "oksen" <oksen@...> wrote:
>
> I'm getting slight banding especially in the both ends on a A6 
> landscape print on epson matte HW. I have tried a lot of combinations 
> including increasing shadow darkness and gamma with no result. I print 
> in 2800dpi as 1440dpi results in even more banding. Same image printed 
> in Photoshop at the same time has absolutely no banding, so it must be 
> related to the rip. On semigloss I had the same problme plus the ink 
> never dries, so that's why I now go for the matte paper.
> Any suggestion highly appreciated, as this RIP seems to be able to get 
> rid of the colorcast produced by photoshop on the 1800.
> thanks in advance,

One banding "cure" for QTR that works well for me is to add a "micro
jaggie" border to your print. The dither in the version of the GIMP
print engine used in QTR doesn't deal with uniform areas well. If you
randomly make about 1/3 the pixels on all four edges of the image
white, the dither settles down remarkably well. Your original image
has to be at least 300dpi when you do this, or you're going to see
"teeth" around the edges.

Interesting idea. Could you elaborate on your workflow for selecting and whitening the pixels 30%, and maybe post a sample image?

Here's what I tried. In a 360 dpi test image, I did Select all > Select > Modify border > 20 pixels > and used the regular noise filter at 75% to create a jagged edge. This reduced banding somewhat, compared to an identical printout without the added noise, but didn't eliminate it. I also tried 25% and 100% noise but 75% worked best.

My testing used EEM with the EEM neutral profile, printed at 1440 (better) on a 1280 with UT2 inks. I haven't found 2880 to make a significant difference with respect to banding and I'm reluctant to use all that extra ink, since I make very large prints.

Mark

--- In QuadtoneRIP@yahoogroups.com, "koloshor" ; wrote:
>
> --- In QuadtoneRIP@yahoogroups.com, "oksen" oksen@ wrote:
> >
> > I'm getting slight banding especially in the both ends on a A6
> > landscape print on epson matte HW. I have tried a lot of combinations
> > including increasing shadow darkness and gamma with no result. I print
> > in 2800dpi as 1440dpi results in even more banding. Same image printed
> > in Photoshop at the same time has absolutely no banding, so it must be
> > related to the rip. On semigloss I had the same problme plus the ink
> > never dries, so that's why I now go for the matte paper.
> > Any suggestion highly appreciated, as this RIP seems to be able to get
> > rid of the colorcast produced by photoshop on the 1800.
>; > thanks in advance,
>
> One banding "cure" for QTR that works well for me is to add a "micro
> jaggie" border to your print. The dither in the version of the GIMP
> print engine used in QTR doesn't deal with uniform areas well. If you
> randomly make about 1/3 the pixels on all four edges of the image
> white, the dither settles down remarkably well. Your original image
> has to be at least 300dpi when you do this, or you're going to see
> "teeth" around the edges.
>