Weirdness with RawTherapee and a colour management. Please help me understand what's going on.

OK, so I did a bit of an experimentation. I mentioned that if I change the working profile in RT from the defeault ProPhoto to sRGB, things are fine. So I exported an imaged with the ProPhoto working profile selected, (and it looks crazy vivid and saturated in RT, but fine otherwise), and then, I exported the same image again, this time with sRGB selected as a working profile.

I opened both images in GIMP and gthumb, which are both color managed and use the system profile and the images are IDENTICAL. There is no difference at all, whatsoever.

In which case, I guess the question becomes how do I make RT use sRGB as the default working profile?

You are not supposed to use srgb as working color profile. There is no room for calclulations in srgb.
Use some proper desktop environment. Gnome is broken.

Which ones are proper DEs?

Basically every desktop environment or window manager except gnome.

Hah! It’s a pitty. I do love Gnome…

However, I am already on a fresh Arch installation running KDE. I’ve been meaning to give it a proper try for years.

Hm, I think Pascal (and probably many others) runs dt on Gnome w/o issues, so might be something RT specific?

There are two sources for the profile: colord and the X atom. darktable-cmstest says they are set to the same value on my machine (using KDE).
Now, just to be sure, I actually run the following as part of the script that launches darktable – there were times when it was needed to help the atom and colord report the same value:

dispwin -I "/oldhome/shared_data/media/digicam/colour-management-profiles/dispcalGUI/storage/HP ZR22w #1 2022-08-20 18-52 0.3127x 0.329y sRGB S 1xCurve+MTX/HP ZR22w #1 2022-08-20 18-52 0.3127x 0.329y sRGB S 1xCurve+MTX.icc"
dispwin -V "/oldhome/shared_data/media/digicam/colour-management-profiles/dispcalGUI/storage/HP ZR22w #1 2022-08-20 18-52 0.3127x 0.329y sRGB S 1xCurve+MTX/HP ZR22w #1 2022-08-20 18-52 0.3127x 0.329y sRGB S 1xCurve+MTX.cal"

Maybe try something like that, and see if it helps. Sorry if you already tried that and I missed that part, I have been a bit busy and was not able to follow the thread.

Ok it’s a while ago that I tested gnome color management, will have another look at it. But problems with gnome color management quite regularly pop up here. And you might not notice the problem if you have a “normal” srgb screen.
If it was fixed, maybe I’ll even use gnome…

Yes but with GNOME 43. Here it is GNOME 44 + Linux 6.3. Some very recent components on the system, maybe a regression!

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Quite possibly, because I have been using Gnome with zero issues since 2020. Only now, in the last few days since it updated to 44, ia when I started having troubles.

The same exact behaviour on KDE… I’m at a loss…

It might be wise to read up about what RT’s Working Profile is and does
— and what Output Profile is and does: Color Management - RawPedia

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Ok, fair enough. I understand that

HOWEVER, why then, does not RT, when specifically instructed to use the system’s main colour profile, show the same image GIMP (or Firefox, or gthumb, or Gwenview) does when instructed to use the system’s main colour profile?

The only way I am able to make it do this if I enable soft-proofing, which, if I understand correctly, simply simulates what the image looks like on a system that uses said colour profile, but I already chose that behaviour when I told it in the preferences to use the system’s main profile.

This is blowing my mind!

System profile is generally your monitors (hopefully calibrated) ICC profile. Your workinf profile is separate and different profile.

I get that, and yes, the .icc profile is generated by DisplayCAL, following calibration. But you’re not answering my question.

Why doesn’t RT show the same image GIMP does when they’re both using the same .icc profile?

I don’t think you’ve given us enough information to adequately answer that question, hence the lack of answers.

You’d need to detail all the ICC profiles in your workflow for each application. If they’re all 100% the same and you load the same tiff into both RT and GIMP, then they should display the same.

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There are no “all profiles”. I use a single .icc profile in my workflow. I install it as a system profile and just enable “use main system profile” in all apps.

But… In RT I load a raw and in GIMP I load the tiff RT exports… Shouldn’t they still display the same? They used to, for the longest time…

If your Working profile is your systems’ calibrated monitor profile, that is not optimal.

Generally there are several profiles at work: input, working, display, and output.

You misunderstood, likely due to bad wording on my side.

My working profile is ProPhoto, display is the calibrated system profile from DisplayCal, output is sRGB and input… I’m not sure and I’m not at the computer right now.

Most probably it’s your camera profile (or the profile your input is encoded in, when editing JPG/TIFF/PNG and so on).