[argyllcms] Re: Very poor results with 1000+ patch target.
- From: "Brad Funkhouser" <brad.funkhouser@xxxxxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Sun, 12 Oct 2014 10:22:41 -0500
Mike,
I started getting better results specifically in yellows when I went to a 2
stage profiling process.
Stage one is a 646 patch target using targen's default patch spread.
targen -v -G -d2 -g7 -e2 -B2 -f646 646_Target
I read that target and create a profile.
Stage two uses that 646 patch profile as a guide so targen knows how to create
a perceptually uniform 2584 patch spread (-I does the perceptually uniform
part). This spread makes sure the yellows get equal patch coverage.
targen -I -v -G -d2 -g17 -e2 -B2 -f2584 -c646_Target.icm 2584_Target
I then concatenate the 646 data with the 2584 data to build a final 3230 patch
profile. That final step is probably overkill, but I just can't handle leaving
good data behind.
Hope this helps.
- Brad
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx] On
Behalf Of Michael Gallagher
Sent: Sunday, October 12, 2014 2:43 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Very poor results with 1000+ patch target.
Thanks for the continued help everyone! Kamil, one of the colors that seemed to
be lacking after creating this profile were the yellows. Could you elaborate on
what I would need to do in order to optimize the profile for yellows,
specifically? I'm a bit lost on how to use this power parameter you referred to
that allows me to improve the colors that are important to me. I did read the
documentation on targen but the -p flag is still a bit confusing to me.
Thanks again.
Mike
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On Wed, Oct 8, 2014 at 4:04 AM, Kamil Tresnak <kamil.tresnak@xxxxxxxxx> wrote:
Hello Michael,
congrats!
So problem was in measuring procedure?
As a next step, if you wish experimenting a make some progress, i would
recommend chart with little bit more patches, you probably do not need
thousands of patches, but somewhere around 1500 can give you more satisfied
results (see Argyll doc, you can experiment with power parameter and cover
colors which are important for you).
Regards,
Kamil
On Wed, Oct 8, 2014 at 6:18 AM, Michael Gallagher <gallaghermikey@xxxxxxxxx>
wrote:
Success! I made a 524 patch sheet, and using the ruler and slit I was able to
get this on running colprof:
Peak err = 1.633284, avg err = 0.377664, RMS = 0.441556
Here's the IT3 for anyone interested:
https://www.dropbox.com/s/yjdn3a8lxyls2h8/Arches_524_i1.ti3?dl=0
I'm assuming this is pretty good, right? Either way, the resulting test print
was, by far, the best that we've seen. My wife and I are very happy with it.
Thank you all for the help. The next step will be to figure out the scanner's
accuracy, since that does seem to be off slightly.
Kamil and Alan: It turns out the ColorSync app DOES correctly print out targets
(of course, when "Print as color target" is selected). To test this I cropped a
strip of patches from a target, and printed two of them side by side. One with
ColorSync and the other with Adobe CPU. When comparing the two rows, there is
no difference between them at all.
Matthew: we're in northern Utah. The processes you mentioned sound very
interesting, and I would love to see that PDF. My understanding of color
matching is quite limited (my wife is the artist, but I'm a CS student and I'm
comfortable on a command line so figuring out ArgyllCMS became my thing), but I
am interested in seeing how others do manage to do stuff like this. Do you coat
your papers, or use inkjet watercolor paper, or anything of the sort? One thing
I'm noticing is that the thin lines don't seem to be quite as sharp when
printed. It's not that bad though. I'm assuming this is just because I'm
printing on a paper not meant for printing.
Graeme: Thank you very much for your suggestions. A couple questions: is there
much to be gained from optimizing the profile I have? e.g. running targen -c
with my new ICC profile. Also, after running colprof -v, the ICC file shrinks
in size. It went from 1.2 MB to 279 KB. Is that profile still usable?
Thanks again,
Mike
On Mon, Oct 6, 2014 at 1:11 AM, Kamil Tresnak <kamil.tresnak@xxxxxxxxx> wrote:
Hello Michael,
maybe, the problem is in the printed charts, maybe there is a
difference between printed chart and ColorSync PDF export. Your
printed chart - seems like OK? Maybe you can find some colors which
are exactly same (CMYK source valueas) on both charts (maybe full
c/m/y) and make spot color measuring to ensure that you dont have
problem with printing output.
Regards,
Kamil Tresnak
On Sun, Oct 5, 2014 at 4:01 AM, Michael Gallagher
<gallaghermikey@xxxxxxxxx> wrote:
> Hmm... here's something I just noticed. In ColorSync, when I select "Print
> as color target", the colors in the little preview window end up changing
> drastically. Is this normal? I saved the preview as a PDF on the bottom of
> the Print window to show you guys. Here they are:
>
> Original Argyll generated TIF target:
> https://www.dropbox.com/s/kfp78d7oytepynh/1050_Arches%20Original.tif?dl=0
>
> ColorSync Target saved as PDF:
> https://www.dropbox.com/s/b6pvvsgniw9misz/Arches%20ColorSync%20Target.pdf?dl=0
>
> I'm going to try using Adobe's Color Print Utility to see if the same thing
> happens during the print.
>
> On Sat, Oct 4, 2014 at 7:39 PM, Ben Goren <ben@xxxxxxxxxxxxxxxx> wrote:
>>
>> On Oct 4, 2014, at 6:23 PM, Michael Gallagher <gallaghermikey@xxxxxxxxx>
>> wrote:
>>
>> > Forgot to ask again: After I make this new target, is there any way to
>> > generate targets/patches from a JPEG to optimize the profile?
>>
>> That sort of thing is much more useful for input (camera or scanner)
>> profiles. In your case, what you'll want to do is use the "basic" profile
>> you're about to create to "pre-condition" the patch generation algorithm in
>> targen; see the "-c" option.
>>
>> b&
>
>
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