[argyllcms] Re: Very poor results with 1000+ patch target.
- From: "Matthew H. Owens" <mho@xxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 4 Oct 2014 22:47:04 -0700
Michael, what part of the world are you in? We can do quite
reliable reproduction of watercolors on cold press paper. I use the
Advanced color profiling system that was developed with argyll for Cruse
Digital by a fellow list member Klaus Karcher. It uses a custom built
1800 patch target made of real world pms inks and traditional art pigments
found in museums. The output print profiles are made in house by me
using Ergosoft V14 and Color GPS, using a eye one pro
spectrophotometer. Klaus evaluated our workflow using the color target
itself and found it quite accurate from end to end. Stanley Smith and Dr
Roy Burns from RIT imaging lab also evaluated this scanner against a wide
sampling of camera systems used in Museum capture settings. If you like
I can send you the PDF docs on how they did it, as well as the RIT
report.
Matthew H Owens
Founder
Druidian Archival Service
Druidian.org
Treasurer
Flyingovertime.org
An educational 501c3 organization.
On Oct 4, 2014 10:57 AM, "Michael Gallagher" <gallaghermikey@xxxxxxxxx>
wrote:
> 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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