QTR-Quadtone RIP

If I can help : please see below.
Olivier

--- In QuadtoneRIP@yahoogroups.com, "Mark Stracke" 
<markastracke@y...> wrote:
>
> I'm having trouble linearizing an 1160 with piezotone inks. I get 
the
> Ink Pattern printed well and have a limit to set in the curve I am
> making. The question is: how to determine the values I should enter
> for the three grey dilutions? I'm on a Mac..
> 	
I have the same setting except a 1290 and XP, I assume you use only 4 
parts of grey on a 1190.

> 	When I try to linearize based on an included curve for piezo 
inks I
> get an error regarding the densities not constantly increasing. The
> readings I get from my eyeOne do seem to be increasing throughout 
the
> scale, sometimes only by .1, but they do increase. This error 
problem
> is why I am trying to build my own curve from scratch.

This is the way I adopted too. So first look for a DEFAULT INK LIMIT 
by measuring the darkest (densier) patch of the Ink Pattern with the 
smallest % (you should be somewhere 60-70%). I decided to take the 
habit to limit a little more than balck boost is the way later to 
increase Dmax.

Reprint with Ink limit (slider pushed a bit on the right in the main 
QTR window, see Tom's tuto for images)at the corresponding %tage. 
Make sure to re-measure the K line from 100% to 70%, density MUST 
decrease.
> 	
> 	I measured the max density patches on the other three inks. 
The
> values are in L and converted to density. Do I use these numbers to
> calculate the entries for my curve? And if so how? Or am I totally 
off
> base. Any help would be appreciated.

Now you can measure the 100% patch of the other greys and convert it 
into a %tage of K. Here I'm just copying another post :
"
we are looking for is what would match 1.29 (the 100% light-black)
so in the black ramp we have: patch 40 is 1.22 and patch 45 is 1.33
imagine that we had intermediate patches 41, 42, 43, 44 -- which is
most likely to match the 1.29?

mathematically what you doing is: 5 levels (i.e 45 - 40) is a 
difference
of 1.33 - 1.22 = 0.11 but we only want 1.29 - 1.22 = 0.07
so (0.07 / 0.11) * 5 = 3.2 levels i.e. 40 + 3.2 = 43.2

Or:
wanted-diff-levels = total-diff-levels * (wanted-diff-density /
total-diff-density)
3.2 = 5 * ( 0.07 / 0.11 )
"

Now quickly since you know : you set up your curve, Black Boost (110-
115% of default ink limit, Highlight (4)/shadows (8); overlapping 
around 10-15% to have some dark grey ink with K...
Now print the stepwedge with this raw curve (you've named and saved 
it prior to this) possibly at 108% to have large patches on A4 and 
measure more easily, measure it, drop it to the linearize droplet, 
reprint the now linearised stepwedge, remeasure with the eye-one, 
produce the file (either from a PM5 .txt example or apparently in any 
format with the latest version) to drag-drop to Create-ICC. And 
you're done. 

If I'm wrong somewhere (I do it from memory), someone will surely 
point it out.

Save your qidf and icc files in a safe place, this is all you need to 
re-create the curves and the results.
> 	
> 	
> 	
> btw, I have worked through this process before with the freeware Mac
> program on 10.1 and 10.2. I stupidly threw out my old version and 
the
> curves that had worked so well when I installed the latest version 
to
> check it out. So I have some experience and have achieved success in
> the past. 
> 
> 
> Thanks in Advance
> 
> Mark Stracke
>