QTR-Quadtone RIP

Hi everyone. I am new to QTR... so please be gentle. I recently acquired a Spyder 1005 Spectrocolorimeter. I decided to profile my setup which is as follows :

Epson 1400
MIS EB-6 inks (6 carbon grey positions)
PremiereArt Smooth Fine Art Paper

I've been using an Epson driver workflow up to this point, but I feel like I wasn't getting the full potential of the 6 inks.

After doing lots of reading, I created a custom ink/paper profile. I did the initial calibration to set the ink limits, with no linearization and recommended defaults. The initial 21 patch target looked pretty good... with good readings from the 1005 indicating increasing densities in all the patches, with the dmax around 1.63. I next followed the linearization procedure. After entering the density values in the linearization curve fields and reprinting the test target, I noticed no significant differences in the density readings. They were off quite a bit from the "optimal dmax" grid for the 1.63 dmax of the paper. It's almost as though the curve was not being applied. I tried a few things like closing and restarting QTR, and switching curves back and forth to make sure it reloaded my custom one.

Visually, the test chart appears to be too dark in the mid tones, and the patches are very close in appearance from 70 to 100. 

Any tips on what I should try next? Should I use the LAB L measurements instead of the density measures in the curve settings?

I don't have the profile here currently, but I can post it later tonight. Any ideas in the meantime?

Thanks - Sean

Hi Sean,

Others with more experience will probably chime in but, in the meantime, I'll suggest:

1)measure Lab L instead of density

2)try to achieve a fairly linear curve before you linearize. The linearization checker spreadsheet available here is a useful tool - http://www.piezography.com/PiezoPress/blog/piezography-k7-inks-and-curves/checking-your-linearization/

3)once you've achieved a fairly linear curve, measure Lab L once again and input that data into the curve's linearization 

Mark 


--- In QuadtoneRIP@yahoogroups.com, "supracode" <seanu@...> wrote:

>
> Hi everyone. I am new to QTR... so please be gentle. I recently acquired a Spyder 1005 Spectrocolorimeter. I decided to profile my setup which is as follows :
> 
> Epson 1400
> MIS EB-6 inks (6 carbon grey positions)
> PremiereArt Smooth Fine Art Paper
> 
> I've been using an Epson driver workflow up to this point, but I feel like I wasn't getting the full potential of the 6 inks.
> 
> After doing lots of reading, I created a custom ink/paper profile. I did the initial calibration to set the ink limits, with no linearization and recommended defaults. The initial 21 patch target looked pretty good... with good readings from the 1005 indicating increasing densities in all the patches, with the dmax around 1.63. I next followed the linearization procedure. After entering the density values in the linearization curve fields and reprinting the test target, I noticed no significant differences in the density readings. They were off quite a bit from the "optimal dmax" grid for the 1.63 dmax of the paper. It's almost as though the curve was not being applied. I tried a few things like closing and restarting QTR, and switching curves back and forth to make sure it reloaded my custom one.
> 
> Visually, the test chart appears to be too dark in the mid tones, and the patches are very close in appearance from 70 to 100. 
> 
> Any tips on what I should try next? Should I use the LAB L measurements instead of the density measures in the curve settings?
> 
> I don't have the profile here currently, but I can post it later tonight. Any ideas in the meantime?
> 
> Thanks - Sean
>

Thanks Mark...

I'll try doing the measurements in Lab instead of density. As far as improving the pre-linearization... Should I increase the point where the darker inks kick in... ie if full black is measuring at %90 change it to 95% and so on down the line for each ink? It sounds like I'll be burning through a lot of ink and paper.




--- In QuadtoneRIP@yahoogroups.com, "mccarvill" <mccarvill@...> wrote:

>
> 
> 
> Hi Sean,
> 
> Others with more experience will probably chime in but, in the meantime, I'll suggest:
> 
> 1)measure Lab L instead of density
> 
> 2)try to achieve a fairly linear curve before you linearize. The linearization checker spreadsheet available here is a useful tool - http://www.piezography.com/PiezoPress/blog/piezography-k7-inks-and-curves/checking-your-linearization/
> 
> 3)once you've achieved a fairly linear curve, measure Lab L once again and input that data into the curve's linearization 
> 
> Mark

Before burning through more ink and paper testing your custom curve, maybe try one of the `canned' Eboni-6 curves by Paul Roark and see what you get. You should be seeing a gradual darkening from 70% through 100%, whereas your initial post suggested you're not. 

That said, if you're getting 100% black at the 90% patch, your default (K) ink limit or black boost might be too high. The ink limit on your next highest density ink after K (I believe it's C) also might be too high. 

Also, I'd recommend first reading through the QTR user guide and Paul Roark's PDF on Eboni-6 (Paul's Web site in general has a wealth of information). I'd also suggest examining closely Paul's  Eboni-6 profiles, looking at how he constructed them -  the densities, and ink limits, and how one ink blends into the next. He also wrote a PDF on Eboni-4-Plus that has a nice section on building QTR profiles. 

Mark 


--- In QuadtoneRIP@yahoogroups.com, "supracode" <seanu@...> wrote:

>
> Thanks Mark...
> 
> I'll try doing the measurements in Lab instead of density. As far as improving the pre-linearization... Should I increase the point where the darker inks kick in... ie if full black is measuring at %90 change it to 95% and so on down the line for each ink? It sounds like I'll be burning through a lot of ink and paper.
> 
> 
> 
> 
> --- In QuadtoneRIP@yahoogroups.com, "mccarvill" <mccarvill@> wrote:
> >
> > 
> > 
> > Hi Sean,
> > 
> > Others with more experience will probably chime in but, in the meantime, I'll suggest:
> > 
> > 1)measure Lab L instead of density
> > 
> > 2)try to achieve a fairly linear curve before you linearize. The linearization checker spreadsheet available here is a useful tool - http://www.piezography.com/PiezoPress/blog/piezography-k7-inks-and-curves/checking-your-linearization/
> > 
> > 3)once you've achieved a fairly linear curve, measure Lab L once again and input that data into the curve's linearization 
> > 
> > Mark
>

mccarvill <mccarvill@...> wrote:

> **
>
>
> Before burning through more ink and paper testing your custom curve, maybe
> try one of the `canned' Eboni-6 curves by Paul Roark ...
>

My Eboni-6 write-up is at  http://www.paulroark.com/BW-Info/Eboni-6.pdf .

Probably my best QTR workflow explanation, however, is in
http://www.paulroark.com/BW-Info/Eboni-4-Plus.pdf
at page 11 and following.  (By the way, profiles that are for Eboni-4 work
with an Eboni-6 setup, but just use 4 positions.)

I hope this helps.

Paul
www.PaulRoark.com


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

Thanks for the replies. I'll do some more reading... and take a look at the profiles. Thanks for piping in Paul... All of the info you have provided on your site, and in the discussions is very much appreciated.

Sean

--- In QuadtoneRIP@yahoogroups.com, Paul Roark <roark.paul@...> wrote:

>
> mccarvill <mccarvill@...> wrote:
> 
> > **
> >
> >
> > Before burning through more ink and paper testing your custom curve, maybe
> > try one of the `canned' Eboni-6 curves by Paul Roark ...
> >
> 
> My Eboni-6 write-up is at  http://www.paulroark.com/BW-Info/Eboni-6.pdf .
> 
> Probably my best QTR workflow explanation, however, is in
> http://www.paulroark.com/BW-Info/Eboni-4-Plus.pdf
> at page 11 and following.  (By the way, profiles that are for Eboni-4 work
> with an Eboni-6 setup, but just use 4 positions.)
> 
> I hope this helps.
> 
> Paul
> www.PaulRoark.com
> 
> 
> [Non-text portions of this message have been removed]
>