Hi Sebastian,
I have noticed the same tendency with ArgyllCMS in general.
I am not complaining though, Graeme's software is extremely useful to me,
and of a very high standard.
What I did was to use a 3d lut editor (3DLUT Creator) to create some colour
edits.
Mainly to shift the blue/magenta hues a bit towards the blue direction but
also for some other (minor) adjustments.
This software can output the luts in many different formats.
I use the very common .cube type.
Then, my software 'translates' the rgb .cube file into an abstract
(Lab->Lab) ICC profile.
This profile is then used during creating of the (updated) ICC output
profile, again using ArgyllCMS.
ArgyllCMS allows the application of the abstract profile to all B2A tables,
or to individual tables.
All this works really well !
Using the editor allows for great freedom in creating colour edits. And it
is good fun...
Greetings,
Auke Nauta
Sebastian Parborg wrote:
During the past year I have tried to properly profile an Epson Stylus Pro
7880 large format printer using Argyll.
During this time I have tried Argyll versions 2.1.0 up through 2.2.1.
I'm currently using Gentoo Linux and the Gutenprint open source drivers to
control the printer. I am using a i1Studio to read the printed test
charts from the printer.
i1Studio info:
Instrument Type: ColorMunki
Serial Number: 4003607
Firmware version: 512
Chip ID: 01-85FE381A00004C
Version string: 'i1Studio FW V2.00 Build Nr. 1310'
Calibration Ver.: 6
Production No.: 187214
The issue I'm having is that no matter what, all the blueish hues are
shifted to purple. If this was a very low quality printer, I could
concede that it would not be good enough for this. But I know it can
produce blue hue colors.
Just to be clear, I'm not talking about that 100% cyan and 100% magenta
has a purple tint to it. I'm talking about that my profiles "corrects"
100% cyan and 70% magenta colors to 100% C and M.
So even if I try to use "safe" blue colors, it forces the printer to
print purple. The other colors looks fine, which is also reflected in
the gamut of the generated profiles.
So to me it seems like the profile I generate forces all blue hues into
purple.
I have:
1. Profiled in RGB and CMYK mode with no visible difference.
(Both on what I send to the printer and if the Argyll profile is CMYK
or RGB)
2. Made sure no color correction is going on printer or Linux wise.
I have made profiles both in "Uncorrected" and "Raw" mode on the
printer.
3. I have followed different Argyll guides:
http://argyllcms.com/doc/Scenarios.html#PP1
<http://argyllcms.com/doc/Scenarios.html#PP1>
http://rawtherapee.com/mirror/dcamprof/argyll-print.html
<http://rawtherapee.com/mirror/dcamprof/argyll-print.html>
https://encrypted.pcode.nl/blog/index.html
<https://encrypted.pcode.nl/blog/index.html> %3Fp29.html
https://askubuntu.com/questions/668345/printer-color-management-how-do-i-calibrate-my-printer
<https://askubuntu.com/questions/668345/printer-color-management-how-do-i-calibrate-my-printer>
Just to make sure that I didn't miss anything silly.
All of them gave me the same result with nearly if not all blue hues
shifting to purple.
4. I have used spotread to read color swatches from Pantone and
comparing the detected colors to what was expected. While the i1studio
wasn't 100% correct it was close enough for me to rule out that the
sensor is bad. (But I am willing to do more tests in needed)
5. I have manually shifted the colors by tweaking the printer settings.
So 100% cyan and magenta became 100% cyan and 70% magenta. However the
generated profile, as expected, corrects this back so the printer
profile is void of any blue hues.
6. I looked at the Argyll mailing list archives and did see that someone
had a similar problem 11 years ago:
https://argyllcms.freelists.narkive.com/fyw6CpRr/purple-blue-shift-problem-with-epson-printer
<https://argyllcms.freelists.narkive.com/fyw6CpRr/purple-blue-shift-problem-with-epson-printer>
However it seems like the issue was solved.
7. I have also made sure that all ink cartridges are good and print the
correct color. (I've replaced all cartridges at least once and noted
if there was any color change)
I have also downloaded profiles for the printer from 3rd parties.
These profiles do show a very large gamut and more importantly, they do
not have a cut off blue channel (or at least no where near as severe).
However I can't use those profiles as they are for the official drivers
and not the gutenprint driver. So I can not use them.
Seems like the .icc profiles are too large to attach here.
So if anyone wants them I can sent it to them.
Any help would be deeply appreciated as I really want to figure out what
is going wrong.
As I'm running Gentoo, compiling Argyll with patches is no issue.
So if any code changes is needed I can apply and test patches
easily.
Regards,
Sebastian Parborg
