The procedure in Pascal’s blog post is the same procedure I’ve been following for a long time, except I’ve always skipped the calibration step (the colprof step) and profiled my monitor using its native TRC and color temperature) - the only calibration I’ve been doing is to set the monitor brightness to something around 64cd/m^2. My profiles have always had the same shape xicclu curve as your profiles, except the color channels were split.
Recently I’ve been experimenting with using dispcal to calibrate my monitor to have a neutral gray axis, so non-color-managed parts of the desktop will look neutral gray if their corresponding colors are supposed to be gray, such as the new GIMP-2.9 themes. My goal is to make a profile that:
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Looks as neutral and also as smooth as possible up and down the gray scale.
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Shows low or zero chroma values - preferably well under LCH “1” - when using GIMP’s screen “eyedropper” to color pick from the screen itself. I’m not sure exactly how this screen “eyedropper” works, but results do change as the installed system profile is changed, and the picked colors cohere with what my eyes are seeing.
It seems curious to me that using dispcal to calibrate and also at the same time make the monitor profile (using the “-o” switch: http://argyllcms.com/doc/Scenarios.html) produces a profile without that characteristic downward hook at the x-axis of the xicclu curve. Instead the xicclu curve is very close to a straight line, at least if the requested gamma is close to the native gamma reported by dispcal using the “-R” switch.
However, despite the straight-line xicclu graph, the colprof “one step calibrate and profile” monitor profile that I made last night, when black point compensation is turned on in GIMP, seems to “screen color pick” very close to the actual LCH “Lightness” values, which is a nice thing. Here’s a screenshot of the xicclu curves:
I haven’t thought this hard about monitor profiles or spent so much time trying different ways to profile the monitor, for many years. Sigh.
About “installed system monitor profile”: what I mean by “installing a system monitor profile” is using “dispwin -I whatever-filename-the-selected-monitor-profile-has.icc”, or else the equivalent process using displaycal or colord or xicc or oyranos etc. I don’t have colord/xicc/oyranos installed on my system as I find these utilities to be somewhat unpredictable and not friendly to user intervention when the user wants to do something other than what the utility thinks should be done.
In case anyone wants to experiment and doesn’t already know the Argyllcms commands:
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The command to uninstall a system monitor profile is “dispwin -U whatever-filename-the-selected-monitor-profile-has.icc”.
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The command to clear the video LUTS is “dispwin -c”.
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The command to load a calibration file into the video LUTS is “dispwin name-of-cal-file.cal”
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If the monitor profile has a vcgt tag, there’s no need to also load the calibration file as the “dispwin -I” command also loads the vcgt tag information into the video LUTS.
Yes, thanks! for that link, which prompted me to set my gentoo portage “package.mask” file to not allow Firefox or Thunderbird to be updated again. I’ve been increasingly unhappy with Firefox with each “upgrade” - as @afre noted in another thread these recent updates keep changing settings and functionality. I have Pale Moon installed as an alternative to Firefox, but it doesn’t support the full range of privacy/security add-ons.
