QTR-Quadtone RIP

-----Original Message-----
  From: QuadtoneRIP@yahoogroups.com [mailto:QuadtoneRIP@yahoogroups.com]On
Behalf Of Tom Moore
  Sent: Wednesday, November 08, 2006 12:22 PM
  To: QuadtoneRIP@yahoogroups.com
  Subject: [QuadtoneRIP] Re: QTR-2200 printing faint vertical bands


  Steven

  I think the cause may be ink overloading. This issue comes up
  regularly and an archive search for the phrases "banding gaussian"
  brings up a number of messages that might help. The one I have quoted
  below sort of sums up the issue (although others have found that
  adding noise didn't cure the problem, suggesting that its use won't
  cure all banding problems):

  ...quote...
  Re: Banding with semi-gloss printing

  --- In QuadtoneRIP@yahoogroups.com, "David Meddings" <meddings@f...>
  wrote:
  >
  > Quick followup on my own issue:
  >
  > Trying various dithering algorithms with 1440 super or 1440 (both at
  > the better setting) had no effect.
  >
  > Printing at 2880 got rid of microbanding but introduced major bronzing
  >
  > Adding 12.5% monochromatic gaussian noise to the shadows and printing
  > at my normal settings solved the problem.
  >
  > So thanks to Tom Moore and indeed it looks as if there is an issue in
  > the gimp printing side of things.

  Very much so. The gimp print drivers will exhibit microbanding
  whenever the total ink density (just all all 7 channel curves) exceeds
  100%. This is easy to do with a glop curve, since we're typically
  adding glop at anywhere from 10-25% to curves that might have an ink
  limit at 80%, or black boost up to 100%.

  I'm working on a driver with a layering concept as part of GRIP (if
  GRIP ever hits the point of being a useful public beta). The glop
  would go on an "aligned" layer so glop droplets always end up on top
  of colored ink droplets.

  gimp print always interleaves ink, nothing ever really overlaps, and
  you cannot exceed 100% coverage (inks just displace each other, which
  can be a really, really weird looking effect when glop displaces black).
  ... end quote...

  Tom Moore

  --- In QuadtoneRIP@yahoogroups.com, "Steven Karafyllakis" <steve@...>
  wrote:
  >
  > Hello All;
  >
  > I'm tying to get a friend started with QTR on a 2200 and OEM UC inks,
  > and we've run into an odd problem. She's on a Mac-Intel with OS 10.4,
  > using QTR 2.42.
  > The problem: she's getting PRINTED vertical faint minus-density lines
  > in the 95%-100% zone. The lines are diffused, about 1/8" wide, and
  > about 1.4" apart. These are NOT pizza-wheel or roller marks, you can
  > watch them being printed as the paper goes through. We've printed the
  > same black field with both QTR and the Epson driver, and it ONLY shows
  > up with QTR, there's no trace of it with the Epson driver. Can anyone
  > help with this?
  >
  > Thanks.
  >
  > Steven Karafyllakis
  >



  


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