QTR-Quadtone RIP

I am using it at 1440 dpi.

You may be right, I have used 45% and even 40% in the past with  
different inks.

---

I re-did the process limiting inks at 40% and everything worked out  
much better.

Thanks for taking the time to look over my post.

You got me over a hump that was really stumping me.

I guess it pays to be a little more conservative when doing this.

James



On May 6, 2007, at 3:34 PM, Howard Shaw wrote:

> Hi James
>
> One thing I noticed is that your unlinearised stepwedge in step 11 is
> some way from optimum. It gets dark too quickly leaving the 70-100
> shadow areas very compressed. I appreciate that after linearisation  
> you
> are only having problems in the 95-100 range but, if it were me, I  
> would
> be looking to get the initial partitions closer to ideal.
>
> You're using a 50% ink limit and I would hazard a guess that you are
> using a resolution of 2880dpi although you haven't told us that. I  
> would
> try a lower ink limit to get those deeper black values more spread  
> out.
>
> I've not looked at how you've done the partitions but there is
> discussion previously on the list that should help with that.
>
> regards
> Howard
>
> --
> Howard Shaw
> glassman@...
> www.howardshaw.org
>
> James Haney wrote:
> > I am having a challenge.
> >
> > I am in the process of re-creating a set of curves due to some
> > changes in density after a recent service call.
> >
> > I have traditionally had difficulty overcoming the below-explained
> > issue but have either dealt with it or "tweaked" around it.
> >
> >
> >
> >
> > Bear with me, this is a lot of detail but I think it would be a good
> > exercise to document this for public consumption.
> >
> >
> > I am creating two curves, using Cone Piezotone inks.
> > Each curve will be a partition of 4 inks
> >
> > Carbon Sepia Curve: Museum Black, Carbon Sepia Dark, Carbon Sepia
> > Medium, Carbon Sepia Light
> >
> > Selenium Tone Curve: Museum Black, Selenium Tone Dark, Selenium Tone
> > Medium, Selenium Tone Light
> >
> >
> > Environment:
> > - Mac OSX 10.4.8
> > - QTR version 2.5
> >
> > - Photoshop CS2
> >
> > - Epson 7600
> > Piezotone inks
> > Museum Black
> > Carbon Sepia set
> > Selenium set.
> >
> > - Hahnemuhle Photo Rag 308
> >
> >
> > Process:
> > 1) Print the InkSeparation.psd file
> > No color management when opening
> > No color management when printing
> > Printed in Calibration mode
> > Calibration Ink Density 100%
> >
> > 2) Dry the print
> >
> > 3) Find the first point in Black scale where we reach total ink
> > coverage.
> > Visually and with a Densitometer
> > I determined the Default Ink Density should be 50% (Density 1.7 read
> > with Xrite 810)
> >
> > 4) Reprint the InkSeparation.psd file with same settings except
> > Calibration Ink Density set to 50%
> >
> > 5) Dry Print
> >
> > 6) Determine partitioning values for ink overlap for
> > a) Point where 100% density of Carbon Sepia Dark intersects with
> > ramp of Museum Black
> > b) Point where 100% density of Carbon Sepia Medium intersects with
> > ramp of Carbon Sepia Dark
> > b) Point where 100% density of Carbon Sepia Light intersects with
> > ramp of Carbon Sepia Medium
> >
> >
> > The following table displays densitometer reading of every patch.
> >
> > Ink 1 - Black - Unlimited 00 05 10 15 20 25
> > 30 35 40 45 50 55 60 65 70 75 80
> > 85 90 95 100
> > Museum Black - Unlimited 0.05 0.54 0.88 1.13 1.34 1.48
> > 1.56 1.61 1.66 1.68 1.70 1.71 1.72 1.72 1.73 1.73 1.73
> > 1.72 1.71 1.71 1.72
> >
> > Reprint with Calibration Ink Limit set at 50%
> >
> > Readings from resulting print:
> >
> > Ink - 1 Black (limited) 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100 Overlap Calculated values
> > Museum Black (40%) 0.05 0.33 0.54 0.74 0.91 1.02 1.12
> > 1.25 1.35 1.44 1.49 1.53 1.57 1.60 1.62 1.65 1.66 1.68
> > 1.68 1.69 1.70 100.0% 100.0%
> >
> > Ink 2 - Cyan 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Carbon Sepia Dark 0.05 0.18 0.29 0.39 0.48 0.56 0.63
> > 0.70 0.77 0.84 0.89 0.95 1.00 1.04 1.08 1.13 1.15 1.20
> > 1.23 1.26 1.28 36.5% 36.50%
> >
> > Ink 3 - Magenta 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Carbon Sepia Med 0.05 0.11 0.15 0.20 0.24 0.27 0.32
> > 0.35 0.40 0.44 0.47 0.50 0.54 0.57 0.60 0.62 0.66 0.68
> > 0.70 0.73 0.75 38.0% 13.87%
> >
> > Ink 4 - Yellow 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Selenium Light 0.05 0.08 0.09 0.11 0.13 0.14 0.16
> > 0.18 0.20 0.22 0.24 0.26 0.27 0.29 0.30 0.32 0.33 0.35
> > 0.36 0.38 0.38 48.0% 4.92%
> >
> > Ink 5 - Light Cyan 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Selenium Dark 0.05 0.16 0.23 0.31 0.38 0.45 0.51
> > 0.58 0.64 0.69 0.74 0.79 0.83 0.87 0.90 0.93 0.97 1.00
> > 1.02 1.04 1.07 27.0% 27.00%
> >
> > Ink 6 - Light Magenta 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Selenium Med 0.05 0.10 0.13 0.17 0.20 0.23 0.27
> > 0.30 0.33 0.36 0.39 0.42 0.44 0.47 0.49 0.51 0.54 0.56
> > 0.58 0.60 0.62 38.0% 10.26%
> >
> > Ink 1 - Light Black 0 5 10 15 20 25 30
> > 35 40 45 50 55 60 65 70 75 80 85
> > 90 95 100
> > Carbon Sepia Light 0.05 0.08 0.10 0.12 0.14 0.17 0.19
> > 0.22 0.23 0.26 0.28 0.30 0.32 0.34 0.35 0.38 0.40 0.42
> > 0.43 0.44 0.46 48.0% 6.66%
> >
> >
> > 7) Create a new Ink Descriptor file for Museum Black plus the three
> > Carbon Sepia inks
> > - I am not currently at the computer that has the file on it to
> > include all of the data, but I inserted the proper VAL= entries in
> > the proper inks.
> >
> > For reference I used the following other values
> >
> > GRAY_HIGHLIGHT=10
> > GRAY_SHADOW=10
> >
> > GRAY_OVERLAP=
> > GRAY_GAMMA=1
> > GRAY_CURVE=
> >
> > 8) Created curve via "Drop-Quad-Profile"
> >
> > 9) Print a 21 Step file
> > - Opened without color managing
> > - Printed without color management
> > - Selected the proper Curve file
> > - Made sure I was using 100% of the curve
> > - No other curves were selected
> >
> > 10) Dry Print
> >
> > 11) Read 21 patches from resulting print
> >
> > Readings shown below
> >
> > 0 05 10 15 20 25 30 35 40 45
> > 50 55 60 65 70 75 80 85 90 95 100
> > 0.05 0.33 0.54 0.74 0.91 1.02 1.12 1.25 1.35 1.44
> > 1.49 1.53 1.57 1.60 1.62 1.65 1.66 1.68 1.68 1.69 1.70
> >
> >
> > Notice the flat spot between 85% and 95%
> >
> > These values prevent a successful linearization
> >
> >
> > 11) Just for grins I "tweaked" the 85% reading to 1.67 to create
> > enough difference to process the linearization.
> >
> >
> > 12) Print a 21 Step file
> > - Opened without color managing
> > - Printed without color management
> > - Selected the proper Curve file
> > - Made sure I was using 100% of the curve
> > - No other curves were selected
> >
> > (Should I be choosing a document profile and a Printer Profile
> > here?)
> >
> > 12) Analyze print
> >
> > The result was unacceptable.
> > Everything looks great except between 95 and 100% there is a sudden,
> > hard drop to max density
> >
> >
> > 13) I re-did the Linearization process using an Eye-One with the 51-
> > Step-Random file and MeasureTool
> > I kept getting "Linearization failed - values do not..." (I
> > can't recall the exact verbiage, but you know the one.)
> > I opened the file in Excel and did some hunting.
> > I sorted the data by L-density and found two lines that seemed
> > out of whack
> >
> > 14) I re-read the values from the print again to rule out user error
> > in the patch-reading process.
> > Again, I got the "Linearization failed - values do not..." error
> > I opened this new file in Excel.
> > I sorted the data by L-density and this time found FOUR lines
> > that were out of whack (not the same ones as the first time)
> >
> > 15) I decided to try to "tweak" the density L values in the first
> > file to make them conform and got the "QTR-Linearize-Data"  
> process to
> > work.
> > I then dropped the file on "QTR-Create-ICC" and successfully created
> > a profile
> >
> > 16) I printed the 21 step file, choosing my freshly minted profile.
> > This time everything looked very good.
> >
> > Sooooo....
> >
> > 17) I followed the same Eye-one Process for Museum Black and the
> > three Selenium inks
> > New Print of 51 step Random
> > Dry Print
> > Read in MeasureTool
> > Save file
> > Drop on "QTR-Linearize-Data"
> > Again, I got the "Linearization failed - values do not..." error
> > However, when I opened the file in Excel to analyze, I noticed that
> > the value for 100% was quite a bit different than the 95% patch. So
> > different that I cannot tweak it in good conscience.
> >
> > Given that the highest density of the darkest Selenium ink is 1.07
> > versus 1.28 for the darkest Carbon Sepia, should I set the ink limit
> > for the Selenium inks to 100% and re-partition, or is there an error
> > somewhere in my process?
> >
> > Any advice is gladly accepted.
> >
> > James Haney
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> >
> > Yahoo! Groups Links
> >
> >
> >
> >
>
>
> 



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