Any suggestion regarding how to fix this black chartread misreadings are welcome.
OK, I'm quoting myself here.
I have tried disengaging the -H flag in chartread and re-read the AX row.
The results are visible in "4Ax4_AXrow(no-H).ti3.txt" attachment.
SAMPLE_ID SAMPLE_LOC RGB_R RGB_G RGB_B XYZ_X XYZ_Y XYZ_Z LAB_L LAB_A LAB
439 "AX1" 0.00000 0.00000 0.00000 0.425937 0.440441 0.144015 3.97849 0.0510300 4.14046
4 "AX14" 0.00000 0.00000 0.00000 0.398379 0.411552 0.106255 3.71753 0.0630325 4.40346
This is something better:
L* is not changed.
a* is correctly near 0 (previously was -2)
b* is still 4 (previously was 6,7), and this is not so good as it should be (less than 1)
Then I have tried engaging -p for single patch read in chartread and re-read patches AX1 and AX14
The results are visible in "4Ax4_AXblacks(no-H_-p).ti3.txt" attachment.
SAMPLE_ID SAMPLE_LOC RGB_R RGB_G RGB_B XYZ_X XYZ_Y XYZ_Z LAB_L LAB_A LAB
439 "AX1" 0.00000 0.00000 0.00000 0.501539 0.523516 0.360842 4.72890 -0.130638 1.34060
4 "AX14" 0.00000 0.00000 0.00000 0.473103 0.494490 0.330598 4.46671 -0.148756 1.45954
This is definitely better:
L* is near the Colorpicker values of 4.7.
a* is correctly near 0
b* is near 1,4 and this is not perfect but still acceptable or at least not so wrong
CONCLUSIONS:
In my setup, with my ColorMunki, Argyll (v1.6.0) "chartread" is not reliable in strip mode regarding the blacks readings.
If the -H (high resolution spectrum mode) option is engaged the results are even worst, so I warn the Colormunki users to disengage the -H option at least.
Acceptable blacks reading are possible only using the single patch -p (spot) reading mode, and not going in strip mode (and even in this case it seems that the b* reading is not perfect).
Please, don't tell me something like "buy an i1Pro2", because in reality the little colorMunki work perfectly for blacks reading even in strip mode, if used with their x-Rite software, so it is not an hardware limitation, it is a problem in the way chartread and Argyll drivers are interpreting the ColorMunki data.
But there is something more to add.
I own a i1DisplayPro which I use for display calibration.
After all of this I have tried to calibrate my screen using Argyll+dispcalgui
with the i1DisplayPro and then with the ColorMunki.
Do you want to know what was the results?
The screen profile made with the i1Displaypro was perfect (I have always used the colorimeter for the screen),
but the screen profile made using the ColorMunki was somewhat screwed in the blacks showing a purple cast!
So, this is a confirmation that the problem is in the coupling Argyll+Colormunki.
The Colormunki used with X-Rite software is good and reliable, if used with Argyll there could be big problems in the blacks readings (for print and for screen too).
The i1DisplayPro is perfect for screen even using Argyll+dispcalgui.
So, the bottom line is that I think I'm screwed now.
I don't care to avoid the use of the CM for screen, I always used the I1DisplayPro for this, but for the print profiles, reading 1000 patches one by one is a real pain and I don't know if I will go for it.
This is sad, because I have to stick with the limited CM software for the printer, and I'm not happy because I think that Argyll could produce higher quality profiles.
Obviously my above conclusion are limited to my explained experience, it could be nice if someone else could be able to replicate the issue and share the results.
I'm very curious if similar issues could be observed even using the more performing i1Pro2, because it will be really disappointing if the case.
In any case, I hope all this stuff will be appreciated and could be useful for other ColorMunki + Argyll users, because I think this could be a real problem, or at least something to keep under consideration.
Please, let me know your opinion/experience, it will be welcome.
Thanks for the attention for now.
Ciao.
Andrea