Hello dear community. First of all, sorry for my english (my native languange is polish). So the problem is when I turned on "soft proofing" (ctrl+Y), and "gamut warnings" (ctrl+shift+Y), my black lines (lineart) turned green (are marked as out of gamut). My Krita version is 3.3.2 (64-bit Appimage for Linux), but previous versions have the same problem with gamut warnings. Examples here:

My color managment settings:
Soft Proofing - model - CMYK/Alpha /8-bit
Profile - Chemical proof (Coated Fogra 39 have similar results).
Proofing Rendering Intent - Absolute Calorimetric.
Adaptation State - full.
When I tested my drawings in PS, black lines are fine, and not marked as out of gamut. I do not know what is causing the problem, so I need your help.
Thank you in advance for any help.

That's because of the cmyk profile you're using. The default cmyk profile in krita indeed doesn't have a proper conversion for rgb black to cmyk black, but it is the only cmyk profile in the world we're allowed to ship due to copyright reasons. You will need to download and use forgra or swop cmyk profiles, import those into krita and then set them up via image properties for softproofing, as indicated by the manual page

EDIT: Saw that you used fogra. Then... There's just no solution, photoshop must be doing some magic to mark black as never being out of gamut, and lcms, which we use for these kinds of things doesn't.

TheraHedwig wrote: Saw that you used fogra. Then... There's just no solution, photoshop must be doing some magic to mark black as never being out of gamut, and lcms, which we use for these kinds of things doesn't.

Thank you for your comprehensive answer. So, the only solution for now is - don`t worry about gamut warning responsible for marking black as out of gamut, because it`s technical issue.

I guess we should take this up with Maria Marti, the lcms developer, though. Maybe we've just missed a flag somewhere.

Okay, I asked about this, and it's not a but: the problem is that you chose "abolute colorimetric":

To quote:

in the krita post it was written:
[...]Proofing Rendering Intent - Absolute Calorimetric.[...]

In _absolute_ colormetric RI RGB Black (0,0,0) is out of gamut for any real CMYK color space. So this works like intended. PS is showing the same result if you choose _absolute_ colorimetric for proofing there.

Edgar

boudewijn wrote:Okay, I asked about this, and it's not a but: the problem is that you chose "abolute colorimetric":

In _absolute_ colormetric RI RGB Black (0,0,0) is out of gamut for any real CMYK color space. So this works like intended. PS is showing the same result if you choose _absolute_ colorimetric for proofing there.

Currently I have no way to check this out in PS because I replaced Windows with Linux, maybe it is as you have written. But I have tested Krita with many CMYK profiles (Coated Fogra 39, Fogra 27, ISO Coated v2 300% etc.) and combined them with diffrent "proofing rendering intents", from "relative calorimetric" to "perceptual", and the effect is the same. In all cases, black is marked as out of gamut (see my examples in first post).

Then maybe we do have a bug. I've also noticed on testing that converting from cmyk to rgb seems broken. Looks like I won't be able to work on the text tool _again_ tomorrow.

boudewijn wrote:Then maybe we do have a bug. I've also noticed on testing that converting from cmyk to rgb seems broken. Looks like I won't be able to work on the text tool _again_ tomorrow.

I cannot reproduce that. For the problem of the inks: It seems blackpoint compensation is broken. There's two seperate problems here: blackpoint compensation can't be toggled in the image properties because it only checks whether the widget exists, so easily fixable. The second problem is that blackpoint compensation as a flag is being given to lcms just fine, however lcms doesn't seem to do anything with it, which might be an lcms issue, or somethin that changed in between versions? :/

Maybe we should make a proper bugreport, ether how?

EDIT:
1. Images converted regularly do look normal compared to images softproofed. I am at loss whether this is because some flag is missing or lcms' proofing is bugged.
2. The garbled look only happens when doing and undoing colorspace conversion on the same image in semi-rapid sequence because you are trying to figure out if different options have different results.