[argyllcms] Re: Very poor results with 1000+ patch target.
- From: <robert@xxxxxxxxxxxxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Sat, 4 Oct 2014 19:30:51 +0100
Hi Michael,
In general you seem to be doing the right thing. However you shouldn't have
the -H (high res) argument in chartread, or the -T argument (read
tolerance). Only use the -T if you are getting misreads, and then you
should make it >1, not <1.
The Argyll-generated gamut seems quite wrong, but then again so does the
Colormunki-generated one. There are some weird nobs and dips that really
shouldn't be there.
My guess is either that the print is wrong, or the scanning was wrong. Try
rescanning your targets without the -H and -T arguments in chartread. If
that still gives a very poor profile then the most likely problem is with
the prints.
I've never used the Colormunki (I use an i1Pro2) so there could be issues
there that I'm not aware of (could be that with that instrument you would be
better using fewer spot colors).
At any rate you are in the right place to get help.
Robert
_____
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Michael Gallagher
Sent: 04 October 2014 18:57
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Very poor results with 1000+ patch target.
Hi everyone. I have been trying to make watercolor reproductions on
traditional cold press watercolor paper, unfortunately with very mixed
results using existing profiles. Luckily I got my hands on a Colormunki to
fix this, and using the Colormunki software with only 3 targets (130 patches
total) I was able to make the best matched print I've ever made. It's
definitely not quite there though.
So, I thought I'd take it to the next level and produce an even greater
profile, so with ArgyllCMS I generated a target with 1,050 patches, printed
it out using the ColorSync app with the setting "Print as color target"
(this turns off color management based on what I have read), and read it in
with the ColorMunki with the following commands:
targen -v -d2 -f1050 -R -G 1050patch_Arches
printtarg -v2 -iCM -h -t360 -a.6 -m0.0 -M0.0 -P -p190x320 1050patch_Arches
chartread -v -H -B -T0.4 1050patch_Arches
After reading in all the patches, I grabbed my local AdobeRGB1998.icc from
my ColorSync folder (as I've read you're supposed to do), copied it to my
working directory and used this command to generate the profile:
colprof -v -qh -S AdobeRGB1998.icc -dpp -D "Arches 300gsm Canon Pro 100"
1050patch_Arches
And here are the results (I apologize for picture quality) with the original
on top, the Colormunki software profile on the bottom left, and Argyll's
profile on the bottom right. This was printed on my Canon Pro 100 in
Photoshop with relative colormetric selected:
http://imgur.com/CnbDset
Notice the blacks are completely missing in the face and the clipping on the
blue wash on the side. It is difficult to tell from this picture, but there
is a green cast as well. Also, here's a 3D view from the ColorSync app
comparing the Colormunki generated profile and ArgyllCMS, with the smaller
ArgyllCMS profile in color and the Colormunki shown in a white outline. It's
obvious that there's quite a bit less coverage in Argyll's profile. To be
honest, I'm baffled that the gamut is so much smaller considering I used
more than 8x the patches with Argyll:
http://imgur.com/DkJwdy5
Perhaps I've missed a valuable step in generating my profile - based on what
I can see, I did not specify any additional grays with the -g command, hence
the complete lack of gray details. I'm a complete novice at profiling, but I
was really hoping that 1,050 patches would produce a superior profile to the
130 patch Colormunki profile. If anyone has any ideas as to what might have
gone wrong here, or what else I need to do to improve this profile, I would
greatly appreciate any help.
Thank you,
Mike
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