QTR-Quadtone RIP

I have been trying to create my first profile for QTR to match budget Cartridge World matt photo paper to the UT14 ink set.

I used Dave Goldenberg's Matt cool profile ink descriptor (EEM) as a base to work from.

I was assuming that I'd get a relatively straight line of plotted luminosity values at the end of the process.  However, comparing the plots (line chart in Exel) of the Luminosity value of Dave's original profile to my new one, it appears that the original is straighter than my profile. 

Looking at Keith Cooper's test prints made with both these profiles, I can see that Dave's profile gives much smoother transitions than mine, as seen in the round thingumajig at the top.  I can see more detail in the shadows created by my profile, but this may be a function of having a lower maximum density.

I'm thinking I'm not getting something right here so would appreciate any advice.  I have placed copies of the plots in "Photos" in this group

The procedure I used to make the profile was;

Find printer ink limit using inkseparation6.tiff, reading values with Spyder3print.
Reprint inkseparation.tiff to get crossover values.
Using Dave's Ink Description Files as a template, I put printer details in, reset the values for default ink limit and the other two channels used (these were different to Dave's through my earlier checks). I didn't get what the values for Gray Highlight and Gray Shadow were for, so left these at 10 each. Next I used Installcommand to load the profiles into HD/Library/Printers/1400.
Using this profile with Dave's linearise values I printed a 21 step wedge and then read and noted the Density values.  I then put these new values in to replace Dave's linearise values in the original text file for this process, which is in Documents.
Next I dropped this file into Drop-Quad-Profile.  (At this point I'm a bit hazy as I've been sat at the laptop since Thursday, learning the whole process from scratch).
I then installed the new profile and printed a new 21 step wedge.  This is the one I've used to produce my own chart in photo's.

1, any obvious errors in my approach?
2, am I correct assuming the luminosity values plot should be straight(ish)?
3, should I be aiming for a straighter plot?
4, Gray Highlight and Gray Shadow values in the profile are given with different suggested numbers in the different tutorials I've read.  What are these for? and how do you determine what to set them at?
5, the test print indicates poor transitions, would the non-linearity of Density values cause this, or may this to be due to Gray Highlight Gray Shadow values.

Apple OSX 10.8.2
PS Elements 11
QTR 2.7.2

thanks for any help

Ross

I can't help with Mac-related issues (I'm PC), but be sure the 21-step test
print you use for linearization was printed after the previous
linearization values were removed.

The plot in Excel of the Lab L values should be a straight line.

Paul
www.PaulRoark.com

On Sat, Feb 2, 2013 at 3:03 PM, rossfmj <ross.jarvis@...> wrote:

> **
>
>
> I have been trying to create my first profile for QTR to match budget
> Cartridge World matt photo paper to the UT14 ink set.
>
> I used Dave Goldenberg's Matt cool profile ink descriptor (EEM) as a base
> to work from.
>
> I was assuming that I'd get a relatively straight line of plotted
> luminosity values at the end of the process. However, comparing the plots
> (line chart in Exel) of the Luminosity value of Dave's original profile to
> my new one, it appears that the original is straighter than my profile.
>
> Looking at Keith Cooper's test prints made with both these profiles, I can
> see that Dave's profile gives much smoother transitions than mine, as seen
> in the round thingumajig at the top. I can see more detail in the shadows
> created by my profile, but this may be a function of having a lower maximum
> density.
>
> I'm thinking I'm not getting something right here so would appreciate any
> advice. I have placed copies of the plots in "Photos" in this group
>
> The procedure I used to make the profile was;
>
> Find printer ink limit using inkseparation6.tiff, reading values with
> Spyder3print.
> Reprint inkseparation.tiff to get crossover values.
> Using Dave's Ink Description Files as a template, I put printer details
> in, reset the values for default ink limit and the other two channels used
> (these were different to Dave's through my earlier checks). I didn't get
> what the values for Gray Highlight and Gray Shadow were for, so left these
> at 10 each. Next I used Installcommand to load the profiles into
> HD/Library/Printers/1400.
> Using this profile with Dave's linearise values I printed a 21 step wedge
> and then read and noted the Density values. I then put these new values in
> to replace Dave's linearise values in the original text file for this
> process, which is in Documents.
> Next I dropped this file into Drop-Quad-Profile. (At this point I'm a bit
> hazy as I've been sat at the laptop since Thursday, learning the whole
> process from scratch).
> I then installed the new profile and printed a new 21 step wedge. This is
> the one I've used to produce my own chart in photo's.
>
> 1, any obvious errors in my approach?
> 2, am I correct assuming the luminosity values plot should be
> straight(ish)?
> 3, should I be aiming for a straighter plot?
> 4, Gray Highlight and Gray Shadow values in the profile are given with
> different suggested numbers in the different tutorials I've read. What are
> these for? and how do you determine what to set them at?
> 5, the test print indicates poor transitions, would the non-linearity of
> Density values cause this, or may this to be due to Gray Highlight Gray
> Shadow values.
>
> Apple OSX 10.8.2
> PS Elements 11
> QTR 2.7.2
>
> thanks for any help
>
> Ross
>
>  
>


[Non-text portions of this message have been removed]

--- In QuadtoneRIP@yahoogroups.com, Paul Roark  wrote:
>
> I can't help with Mac-related issues (I'm PC), but be sure the 21-step test
> print you use for linearization was printed after the previous
> linearization values were removed.
> 
> The plot in Excel of the Lab L values should be a straight line.
> 
> Paul
> www.PaulRoark.com
> 
Thanks Paul.  I've tried this, however the resulting wedge achieves Dmax (1.57) by 30% stage and just deviated up and down a bit up to 100%.  (Lab plot looks like a scary roller coaster with little interest after the first drop!). I must be doing summat wrong but can't figure out what.  I printed with Printer Profile Gray Gamma 2.2 (same as image) and QTR Gray Matte Paper and both were similar.  QTR won't install with these as the values don't keep rising.  It's now past Midnight here so am retiring and will try again tomorrow.

Ross