Digital BW, The Print

Thanks.  I found with the PFP profiles I had some weird color jumps 
in the shadows (fog being way too bluish for example) and thought 
your method might help keep it realistic.

I downloaded and looked at your curve with the per channel 
adjustments.  I also have PFP and your 21 step grayscale wedge (which 
is VERY useful!)

You seem to be using it to both linearize and get a neutral grayscale 
simultaneously.  Do you have any references on how to do this?  I 
don't have a background in manual curve creation.

Say if step 17 (80%) is L26.47 a= 1.98 b= 6.61

I'd want to counter the postive b by increasing the blue channel 
somewhat and reduce the a by increasing the green channel, but 
overall for this point I also have to either reduce or increase L* to 
linearize the curve.  Is there an equation to assist with this?  
Otherwise it would seem like an awful lot of trial and error.

----------------------------

Also, on an unrelated note, I'm going back and reprofiling my R220 
using UTR2 with glossy media.  By using RPM and checking Microweave 
I'm getting much higher dMaxes- increasing from 2.13 to 2.32 on 
Kirkland Glossy, getting 2.25 on Silver Rag, 2.15 to 2.36 on Harmon 
FB Al, etc.  It also has no microbanding under a loupe which is nice.
Downside is that prints take forever.

Thanks,
Roger


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark" 
<pr_roark@...> wrote:
>
> The color profile I use with the 260 is simply a curves set that 
> makes a grayscale 21-step test file print as a relatively neutral 
> print with a ramp that about matches the Gray Gamma ramp. It was 
just 
> manually made with the usual iterations and a ColorVision PFP 
> spectro.  It works well in the neutral range, which of course is 
how 
> it was made.  It is less accurate with very saturated colors.
> 
> In actual practice, I use it for my color snapshots.  I find that 
> different shots need the layer at different opacities.   It works 
> well enough that I have not bothered to do any more serious 
profiling 
> or switch to another approach.  I do not represent it as 
professional 
> quality profiling -- I'm not making "giclees" with it for the 
> painters in the gallery.
> 
> Paul
> www.PaulRoark.com 
> 
> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Roger" 
> <rsmith02@> wrote:
> >
> > I have struggled to get a R220 to work as well with MISPRO color 
> inks 
> > as it has with MIS UTR2 inks.
> > 
> > Profiles from inkjetart.com, Cathy's profiles and PrintFixPro 
have 
> > all come out with some serious problems as the ICC profiling 
> process 
> > doesn't seem adequate to correct huge the color shifts when using 
> > these pigment inks with a driver that expects very different dye-
> > based inks.
> > 
> > I was intrigued by this method of using adjustment layers instead 
> of 
> > ICCs and was wondering if Paul or anybody could offer advice for 
> how 
> > to derive my own curves for use with the R220.
> > http://www.paulroark.com/BW-Info/R260-Color.pdf
> > 
> > I have a PrintFixPro unit.
> > 
> > I also bought an R1800 hoping that would solve my color issues 
but 
> > the model I got seems to spray ink internally, so I have to have 
it 
> > replaced. In the meantime, back to the R220.
> > 
> > Best,
> > Roger
> >
>