I have two setups, with two Macs and two different displays. One of them is a 5K wide-gamut monitor capable of covering the Adobe RGB color space.
It seems strange to me that darktable behaves differently on the two setups, showing color clipping (with the same image) on one of them but not on the other.
I should add that darktable has the same configuration on both Macs.
I thought that the “Toggle clipping indication” function was independent of the display being used and was related to the output color profile, which in my case is set to “Adobe RGB”.
I’m quite sure it’s a bug now because toggling back and forth to various display profiles make it behave differently and now after fiddling with it seems that both setups are displaying the same out of gamut results.
I just think that darktable for mac isn’t as refined as probably is the Linux version. How can I report this bug?
Unfortunately on MacOS, darktable’s monitor display is limited to sRGB, and this is what you get when selecting “system display profile” - I know it’s confusing, one would expect that the “system display profile” really uses what’s selected in the OS.
Any other profile leads to color mismatches, as the underlying gtk3 framework is hard-coded to using sRGB.
So it’s not a bug in darktable, but a deficiency in an underlying framework on MacOS. Maybe this gets resolved with the upcoming transition to gtk4, not sure.
Clipping uses the histogram profile for its data… Gamut uses what you have set for the softproofing… and the clipping indicator also has modes including single channel clipped, luma only, saturation, and full gamut…also a small change in the threshold often makes a big difference…just a few notes…but as noted by @geni1105 there is a nuance to the display profile using the Mac it appears…
Need to remind myself to set both according to my intended output and fitting to the export profile, i.e. differently for my storage, web posting and printing.
I’m talking about full-gamut clipping. I’m using a custom ICC display profile (created with an X-Rite i1Pro) for both displays. It’s really annoying to be limited to displaying only sRGB colors. I hope this will eventually be resolved.
I also tried a lut based x-rite profile at one time and because of the way the DT processing pipeline works, it would cause issues…the display profile comes before the histogram profile and it can introduce issues and that can be the source of the altered clippings warnings…
You can test this by setting your display profile working profile and histogram profile to linear rec2020…don’t worry about how the image looks…now set your gamut checking as you like so in your case you want full gamut…now change the display profile to your custom icc…if the warnings change then your display profile is not what would perhaps be called well behaved as the warning should be independent of the profile used…unless they are introducing some clipping due to the DT processing architecture… Don’t worry about the changes to the image we are looking at if the gamut warning areas change…This perhaps coupled with the rgb issues around the Mac could be what you are seeing…
In darktable’s pipeline, the display colour profile is part of how gamut check and clipping indicators work. Not ideal, but that’s how it works, and changing that would be very difficult.
The thread contains other comments that may be of interest too you.
Yes, that’s exactly the problem. Changing the display profile changes the way the clipping indicator behaves. I can’t understand why anyone would want this. I mean, if I edit on my laptop or on a full-gamut display, I should get the same clipping information, especially since I want to keep the Adobe RGB color space.
I also don’t understand how this issue could have gone unnoticed from the beginning, or how it’s possible to expect people to work professionally this way. Being able to see and understand gamut limitations and work consistently within a defined color space is pretty much a fundamental requirement of any serious photo editing or image-processing software.
I like darktable. It’s a very powerful app and has a ton of features, but this is quite a significant limitation, especially if you’re trying to use it as part of a professional workflow.
You image won’t look right during your checking but you can see if for now you can work by setting the histogram profile to adobergb, use the full gamut option for the overexposure warnings…use this for gamt and then toggle your display profile on to Adobe…as I said your display wont look right but the warnings and areas out of gamut should be accurate for your colorspace…
You can pick up on some of it here if your are interested… at the bottom of the rest of the thread are references to related and subsequent discussions…