It appears to me that RT lightens up very dark colors or at least dark greys too aggressively, maybe this has something to do with black point compensation.
During the last days I made a few experiments with color management. Among other things I have created several profiles for my screen with different settings with a Spyder 5 and Displaycal. Then I opened the ECI test image with different color managed programs. Apparently, every program has different interpretations of the same screen profile. There are very slight differences and those differences are different with different profiles. However, it appears that in general very dark colors or greys appear black in most other programs. The rendering of Photoshop is the most similar to RT, but it is possible to turn off black point compensation in PS and then the test image looks exactly the same as in Affinity, Gimp or Opera. Deactivating BPC does not seem to do anything in RT though. The only “fix” I found is activating soft-proof or applying the current screen profile to the image when opening/importing it. But then the darkest greys are a bit too dark, anyway darker than in other programs. Also sometimes, depending on the profile type (lut or curves etc), there seems to be a very slight color cast in the middle greys.
I am not sure why this is. Probably I am doing something wrong. Also I have not yet made comprehensive tests with real photos. I think with real photos the effect is proably barely noticeable.
This is quite complicated, I hope someone can understand what I mean. I also attach some screenshots so you see what I mean, but of course I know that they look different on your screens.
I’m not sure quite how to help you since there is not a question in your post, but rather a series of statements.
Perhaps it has something to do with black points, but RT only does what you tell it to do.
Take the profile you created with DisplayCal and your spider and assign it as your monitor profile. This is done via your operating system, not in any application. You do not assign this profile to an image.
You also don’t mention what other profiles you’re using.
In my mind you’ll have these profiles.
Monitor profile. Created using a hardware calibration tool, like ColorMunki or Spyder. You load this profile using your operating system. Do not assign this profile to an image or load it in an application.
Working profile. Set this profile in your applications. Generally is a wide gamut profile like ProPhoto, Rec 2020, Rec 702 or similar. Could also be sRBG if you only do images for the web, or AdobeRBG if you only do images for print.
Output profile. This should be sRBG for the web. AdobeRBG or your printer’s specific profile for print.
I will try it with a more practical example. In this photo, there is a brown spot on the left edge. It is visible (I would not say very clearly) in RT, but invisible in GIMP and all other apps (BPC is active). It is barely visible in PS. I am uploading screenshots but I think it is not possible to see them in a browser.
I think there is nothing worng with my color management settings (but I am not 100% sure). My screen profile is set in Windows and RT.
I also think that one should not apply the screen profile to any photo. However that is one of two ways to make the spot disappear (which is actually the rest of a lamp’s beam after darkening it with the graduated filter in RT). The other way is activating softproof (without printer profile). Is it supposed to work this way? Anyway, checking or unchecking black-point compensation in the color managment settings (in the color tab) in RT does not do anything.
The point is: photos that I developed in RT do not look exactly the same in other color-managed applications (editors like GIMP or Affinity, browsers, image viewers) even though they use the same screen profile. I ususally export them form RT with an embedded sRGB or RT-sRGB profile. But I don’t know. Maybe it is suppesed to work with soft-proofing.
Also, I am confused because I do not knwo whether the brown spot is supposed to be visible or not. Maybe it is a bug in Affinity, GIMP etc.
If I open a file, on the bottom of the window there is a field for the screen profile. If I klick on it a list with all profiles appears. Usually it is the system profile which is chosen. You can also set it in preferences - color managment.
that the apps are actually using the same profile (this is probably true, but just in case…)
that they are using the same rendering intent
that they have the same setting regarding “black point compensation”. Note that for RT this is not in the “color tab” (that is for the output profile), but in Preferences → Color Management:
Yes, thank you, that’s it. But: Is it recommended to activate bpc for the screen or not? Or does it depend on the screen profile type (I heared that some profiles have built-in bpc)?
Anyway, the image looks different (dark colors darker resp. black) in GIMP and Affinity, although bpc is active.
Kind of like it better without bpc, at least RT. But I guess it is not really a matter of taste, is it?
I do not really see a difference between rendering intents, maybe perceptual is less vivid.
I don’t know. I think RT has the most aggressive bpc of all image editing programs I know. But on the other hand, if bpc is off, dark colors are darker than in PS without bpc (or black). At least here.
Btw I checked bpc on my other older Samsung screen. Very dark colors are more visible on it and there seems to be less difference between GIMP and RT in this respect. It was also calibrated and profiled with Displaycal and the Spyder but with slightly different settings as default settings produced a color cast.
I suppose it should be visible … but we’d need to measure the source file to be sure.
I hope it’s a jpeg or tiff with embedded icc profile … (pngs are a bit dangerous due to non standard icc taging)
BTW … is RT’s image brighter on all files (8 or 16 bit, jpeg or tiff or pngs ) ?
Anyway, on these screenshots I see the spot clearly on both … but it’s more intense on RT’s screenshot
