[argyllcms] Re: [i1Studio] Printer profiles shifts nearly all blueish hues to purple
- From: Sebastian Parborg <darkdefende@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 22 Nov 2021 12:41:33 +0100
On Sat, Nov 20, 2021 at 10:47:02AM +1100, Graeme Gill wrote:
Hi,
please provide link/details of:
the .ti3 file
the command line used to make the profile
the resulting ICC profile
the source profile you are using
details about the conversion between source and destination colors - i.e.
intent,
what exactly is performing the conversion etc.
the blue color in the source space that is an example of the problem.
It's not really possible comment without being able to understand/reproduce
the particular issue you have.
Here is all the generated files besides the .tiff file of the test
pattern.
https://drive.google.com/file/d/1ZG2Q6Cxvj6F5lq9tiubq3AwjPIzrSXX9/view?usp=sharing
I have added a .txt file with all the commands used.
I left out profcheck, but I did use that to check if any scanned colors
were way off and needed rescanning.
So people don't have to download the zip to see the commands I'll post
them here as well:
#Generate print out pattern
targen -v -d2 -G -g40 -f1000 semigloss
#Generate print pattern to a tiff file
printtarg -v -iCM -h -R1 -T300 -p 609x440 semigloss
#Scan in the values by hand:
chartread -v -H -T0.4 semigloss
#Generate ICC profile:
colprof -qh -S /usr/share/argyllcms/ref/sRGB.icm -cmt -dpp -D"Epson semimatte
proofing paper" semigloss
Note that I have also tried the official guide as well:
http://argyllcms.com/doc/Scenarios.html#PP1
However no matter which guide I followed that I found online, the same
issue with the blue hues happened.
Note that I am not using any preconditioning profile.
I did once try to print three test charts one after the other and used
the previous chart result as a preconditioning profile. However the
result didn't improve. (For a total of 3000 scanned patches)
I have also tried different color spaces like Adobe RGB instead of sRGB,
but that didn't change anything either.
In addition to that, I tried a lot of different paper types. For
uploaded files I'm using some Semimatte proofing paper from Epson to
make sure that it wasn't a paper issue.
For converting the images to the printer profile, I've tried using
different color managers (the ones that comes with Gnome and Xfce) and cctiff.
It seemingly didn't make any difference which I used.
For all the latest tests I have used cctiff exclusivly and made sure
that no other color management was turned on.
To convert the files I have tried all four rendering intents.
Perceptual (ip), Relative (ir), Saturation (is), and Absolute (ia).
Example command line:
cctiff -v -ip /usr/share/argyllcms/ref/sRGB.icm -ip semimatte.icc in.tiff
out_ip.tiff
cctiff -v -ia /usr/share/argyllcms/ref/sRGB.icm -ia semimatte.icc in.tiff
out_ia.tiff
I have tried to mix and match wildly between the source and destination
intent as well, but to no success.
I've also used the soft proofing functionality provided both by Krita
and GIMP to view the color shift and out of gamut colors.
Both GIMP and Krita in soft proof mode accurately show that nearly all
blue colors are shifted to purple.
I can give complete example pictures if needed.
One of the colors I have issue with is:
(Values are from 0-100 in sRGB space)
R: 20, G: 40, B: 100
And in CMYK:
C: 80, M: 60: Y: 0, K: 0
If I switch the one of the 3rd party profiles when soft proofing, I can
see that while blue highlight of the image are changed, the blue colors
are not shifted to purple.
I also tried to print a gamut map like this after applying my generated
profile:
http://www.gamutvision.com/docs/printest.html
It confirmed that the blue section between pure magenta and pure cyan is
purple.
I hope this in enough information.
Sorry for the long email.
If you want me to test something or give more information, just ask! :)
Regards,
Sebastian Parborg
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