Datacolor User to User Support Group.

--- In colorvision_group@yahoogroups.com, David Miller <dm2363@...> 
wrote:
>
> >
> > I used PhotoShop to Soft Proof the adobe church using 5 profiles
> > (PrintFix Pro 225 and 225 with grays, Ilford profile for R1800 and
> > their Pearl paper, Epson's profile for their glossy Photo and a
> > Profile Prism profile for Epson glossy and the R1800). All 
profiles
> > show the blotches in the sky but at different places. The Printfix
> > profiles show the blotches at the top and across the crosses
> > depending on the intent. Other profiles are at different places in
> > the sky. Darkening or lightening the sky moves the blotches up or
> > down but does not completely eliminate them. I think this is just 
a
> > tough test for any profile; I have not printed the church so I 
don't
> > know if it's visible on an actual print.
> >
> >
> 
> Try printing and measuring 729 patches, and use those colors in
> combinations with your grays measurements. I've done some recent
> testing and closer evaluation of the R800 (same inks as yours, just
> smaller paper) and it really needs the extra patches to avoid 
problems
> in certain areas; the R800/R1800 is tricky to profile with fewer 
patches
> because of its inkset (the extra red and blue inks) and what I found
> is that with 225 patches, I was getting too much saturation and some
> loss of smoothness in faces.
> 
> (this was on both Premium Luster and Harman Gloss)
> 
> So from now on, I'm using 729 patches, always, for the R800, and 
I've
> also done a similar profile for the Canon 9500, also on Harman 
Gloss,
> with 729 patches plus 238 grays.
> >
> 
> David Miller
> Senior Software Developer, Digital Color Solutions
> Datacolor
>
Hi David,

Thanks for getting back.  I built a new profile using the 729 patches 
with the grays as you suggested.  I did not see much difference 
between the profiles using the PhotoShop soft proof.  So, I decided 
to quit pixel-peeping on the monitor and I printed the church on the 
same piece of paper (Ilford Pearl) using the Colorvision profile and 
the Ilford profile.  Looking with a magnifying glass and good light I 
can not see the blotches in the sky (the prints are smallish, about 
3x4). The only differences between the profiles is the Ilford profie 
produces a print that is a little brighter and a little bluer in the 
sky, the Colorvision sky is a little towards purple but still blue.  
The biggest difference between the two is in the lower level 
doorway,  The Ilford profile is a little lighter in this area and 
shows a little more detail.  I may redevelop the profile using some 
of the advanced adjustments. 

It's also possible that I'm bumping into a monotor limitation.  Using 
Photoshop's colorpicker there is only a difference of 1 in the blue 
value across the area that is blotchy.

One possible suggestion for Colorvision.  If Epson printers produce 
targets that are so dark that they are hard to profile you may want 
to consider making a "bright" target.  The software could be adjusted 
to compensate by knowing that the target was "bright" and the color 
readings may be improved.  I noticed that some of the dark areas on 
the targets were very dark to my eye and showed a large difference 
between the reading and the ideal.

Thanks for your help.

Bob Schoner