QTR-Quadtone RIP

I am trying to match the output of two printers, an Epson 2200 with UT7 
inks and an Epson 7600 with UC inks. Because of the diffferent inks 
matching exactly may not be achievable, but ball park is desired. I 
have printed out 21 steps for each and measured them with my PrintFIX 
Pro spectro and for the 2200 is lighter through most of the range. I 
then tried adjusting the Gamma (1.1, 1.25, 1.5) and Gray curve shadows 
and highlights(from 6 to 10) for the 7600 curve in Curve Creation, but 
the output by eye did not change enough to measure. But when I changed 
the Shadow and Midtone values (-20, -6), the steps lightened and 
approached the densities of the 2200.
My question is, why am I not getting changes by adjusting the Gamma or 
the Shadows & Highlight in the Curve Creation? Are my adjustments too 
small, or is something else going on?

I'll take a swing, but Roy and others may want to chime in if I'm 
off base.

First, adjusting the output midtone gamma and shadows ink limits (as 
you have done) is probably the best way to lighten or darken an 
existing linearized profile. 

Assumming you relinearized your profile after adjusting the 
graytones gamma or highlights/shadows values, QTR theoretically 
should internally create and apply an adjustment curve that 
straightens out the measured curve (based on the linearization 
density or L data you input) shown in the Curve Creator|Create 
Curve|Linearization plot between your measured dMax and dMin. 
Therefore you shouldn't see much if any variation.  In my 
experience, tweaking with the graytone values only helps the 
linearization process along. 

--- In QuadtoneRIP@yahoogroups.com, "stasunas" <Astasunas@...> wrote:
>
> I am trying to match the output of two printers, an Epson 2200 
with UT7 
> inks and an Epson 7600 with UC inks. Because of the diffferent 
inks 
> matching exactly may not be achievable, but ball park is desired. 
I 
> have printed out 21 steps for each and measured them with my 
PrintFIX 
> Pro spectro and for the 2200 is lighter through most of the range. 
I 
> then tried adjusting the Gamma (1.1, 1.25, 1.5) and Gray curve 
shadows 
> and highlights(from 6 to 10) for the 7600 curve in Curve Creation, 
but 
> the output by eye did not change enough to measure. But when I 
changed 
> the Shadow and Midtone values (-20, -6), the steps lightened and 
> approached the densities of the 2200.
> My question is, why am I not getting changes by adjusting the 
Gamma or 
> the Shadows & Highlight in the Curve Creation? Are my adjustments 
too 
> small, or is something else going on?
>

Thanks for the response. After much trial and error, I got the output 
to match by adjusting the Gamma, highlights and shadows and 
linearizing. I think I may have had better results earlier if I would 
have linearized after my first 21 step adjustment.
 
Regards,
 
Tony



--- In QuadtoneRIP@yahoogroups.com, "Jeff Randall" <jrandall@...> 
wrote:
>
> I'll take a swing, but Roy and others may want to chime in if I'm 
> off base.
> 
> First, adjusting the output midtone gamma and shadows ink limits 
(as 
> you have done) is probably the best way to lighten or darken an 
> existing linearized profile. 
> 
> Assumming you relinearized your profile after adjusting the 
> graytones gamma or highlights/shadows values, QTR theoretically 
> should internally create and apply an adjustment curve that 
> straightens out the measured curve (based on the linearization 
> density or L data you input) shown in the Curve Creator|Create 
> Curve|Linearization plot between your measured dMax and dMin. 
> Therefore you shouldn't see much if any variation.  In my 
> experience, tweaking with the graytone values only helps the 
> linearization process along. 
> 
> --- In QuadtoneRIP@yahoogroups.com, "stasunas" <Astasunas@> wrote:
> >
> > I am trying to match the output of two printers, an Epson 2200 
> with UT7 
> > inks and an Epson 7600 with UC inks. Because of the diffferent 
> inks 
> > matching exactly may not be achievable, but ball park is desired. 
> I 
> > have printed out 21 steps for each and measured them with my 
> PrintFIX 
> > Pro spectro and for the 2200 is lighter through most of the 
range. 
> I 
> > then tried adjusting the Gamma (1.1, 1.25, 1.5) and Gray curve 
> shadows 
> > and highlights(from 6 to 10) for the 7600 curve in Curve 
Creation, 

> but 
> > the output by eye did not change enough to measure. But when I 
> changed 
> > the Shadow and Midtone values (-20, -6), the steps lightened and 
> > approached the densities of the 2200.
> > My question is, why am I not getting changes by adjusting the 
> Gamma or 
> > the Shadows & Highlight in the Curve Creation? Are my adjustments 
> too 
> > small, or is something else going on?
> >
>

Sounds like your original profiles were not properly linearized or at 
least were not linearized specifically for your printers and their 
idiosyncrasies.

Agreed, you should have relinearized after changing graytone gamma, 
highlights, and shadows values.  Changing them throws off the 
linearization.

--- In QuadtoneRIP@yahoogroups.com, "stasunas" <Astasunas@...> wrote:
>
> Thanks for the response. After much trial and error, I got the 
output 
> to match by adjusting the Gamma, highlights and shadows and 
> linearizing. I think I may have had better results earlier if I 
would 
> have linearized after my first 21 step adjustment.