Digital BW, The Print

Thank you very much!

My first curvers looked like a mountain range and this one had valleys, but
I didn't understand that the curve should be "smooth" or what the curve
represented.

gar



  -----Original Message-----
  From: DigitalBlackandWhiteThePrint@yahoogroups.com
[mailto:DigitalBlackandWhiteThePrint@yahoogroups.com]On Behalf Of Olivier
  Sent: Tuesday, September 12, 2006 1:28 AM
  To: DigitalBlackandWhiteThePrint@yahoogroups.com
  Subject: Re: [Digital BW] 4 color QuadTone setup


  >
  > I have MIS quadtone inks in the epson 3000.
  >
  > My stepwedge is blocky by ink cart..
  >
  > Is the chart supposed to be smooth?
  >
  > Here's my attemp at a curve;
  >
  > PRINTER=Quad3000
  > CURVE_NAME=3000q4test2
  > GRAPH_CURVE=YES
  > N_OF_INKS=4
  > DEFAULT_INK_LIMIT=70
  > BOOST_K=100
  > LIMIT_K=
  > LIMIT_C=30
  > LIMIT_M=30
  > LIMIT_Y=30
  > N_OF_GRAY_PARTS=4
  > GRAY_INK_1=K
  > GRAY_VAL_1=100
  > GRAY_INK_2=C
  > GRAY_VAL_2=63
  > GRAY_INK_3=M
  > GRAY_VAL_3=43
  > GRAY_INK_4=Y
  > GRAY_VAL_4=13
  > GRAY_HIGHLIGHT=0
  > GRAY_SHADOW=0
  > GRAY_OVERLAP=0
  > GRAY_GAMMA=1
  > GRAY_CURVE=
  > N_OF_TONER_PARTS=0
  > TONER_HIGHLIGHT=0
  > TONER_SHADOW=0
  > TONER_GAMMA=1
  > TONER_CURVE=
  > N_OF_TONER_2_PARTS=0
  > TONER_2_HIGHLIGHT=0
  > TONER_2_SHADOW=0
  > TONER_2_GAMMA=1
  > TONER_2_CURVE=
  > N_OF_UNUSED=0
  >

  From what I can see :
  - Boost is set too high, overspraying K. You want boost to be 110-
  115% of Default Ink Limit thus around 77-80% in your case.
  - All Gray Val seems high but I don't know the ink set, so it might
  be valid. However you do not need to limit CMY which are you grey
  densities, since the Gray Val already establishes the relationship
  between K and greys.
  - Shadows and HLs 'd better be smoother (like you'be doing with a PS
  master RGB curve to open up shadows and calm down HL), you need to
  input some datas, probably around respectively 10 and 8. You can load
  a PS curve if more convenient to adjust these.
  - You also want greys to overlap for better smoothness, specially for
  K, this could be 10.

  Those are standard values and a fairly common start to generate the
  linearisation.

  You can now create the curve and visualise the usage of each ink. Let
  me insist on this : you can analyse a lot through those graphs
  without the need to print. I past tended to under-estimate this nice
  feature, it's a free $, time, hassle testing.

  Now, print your stepwedge and measure each patch, those values have
  to go into the linearisation panel of QTR, you click to get the
  linearisation done and you will see the total ink usage curve, the
  smoother the better in my experience.

  Print the stepwedge for final evaluation and you're set. Next is to
  use the profiling tool of QTR with this lastest stepwedge. Other
  approaches use gray spaces or Paul's adjutment curves depending on
  equipment and the way one feels more comfortable.

  Hope it helps.

  Olivier



  


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