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I have a display white point of which drifts from time to time.
I do not really want to rebuild profile each time I encounter that. I do not care about spot-on luminousity (100 or 120 cd/m2) but I care about chromaticity accuracy so I would rather like to measure new white point and rebuild existing profile using new white point data.
Is it possible with displayCal?
Is it possible with ArgyllCMS?
Is it possible to do it with both LUT and matrix profiles?The profile needs to initially have been created with calibration (.cal file needs to exist).
Yes, the profile is selected from the dropdown and was created with dispCal and there also is a .cal file of course.
Selecting “cal” file yields error message saying: “This file does not contain settings”.
However, if I select a profile which has 1D curve (“Tone curve” being defined i.e. anything except “as measured”) this makes the “Update calibration” option active.
So, what is the purpose of this option then?
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Quote from manual:
Settings file
Here, you can load a preset, or a calibration (.cal) or ICC profile (.icc / .icm) file from a previous run. This will set options to those stored in the file. If the file contains only a subset of settings, the other options will automatically be reset to defaults (except the 3D LUT settings, which won’t be reset if the settings file doesn’t contain 3D LUT settings, and the verification settings which will never be reset automatically).If a calibration file or profile is loaded in this way, its name will show up here to indicate that the settings reflect those in the file. Also, if a calibration is present it can be used as the base when “Just Profiling”.
The chosen settings file will stay selected as long as you do not change any of the calibration or profiling settings, with one exception: When a .cal file with the same base name as the settings file exists in the same directory, adjusting the quality and profiling controls will not cause unloading of the settings file. This allows you to use an existing calibration with new profiling settings for “Just Profiling”, or to update an existing calibration with different quality and/or profiling settings. If you change settings in other situations, the file will get unloaded (but current settings will be retained—unloading just happens to remind you that the settings no longer match those in the file), and current display profile’s calibration curves will be restored (if present, otherwise they will reset to linear).When a calibration file is selected, the “Update calibration” checkbox will become available, which takes less time than a calibration from scratch. If a ICC profile is selected, and a calibration file with the same base name exists in the same directory, the profile will be updated with the new calibration. Ticking the “Update calibration” checkbox will gray out all options as well as the “Calibrate & profile” and “Just profile” buttons, only the quality level will be changeable.
Yes, the profile is selected from the dropdown and was created with dispCal and there also is a .cal file of course.
The .cal file needs to come from an actual calibration run. Linear or “Use current calibration” will not work.
That would assume that the whitepoint is the only thing that drifted, which is probably inaccurate – white is made out of a mixture of the primaries, so they have shifted as well. There’s two ways to deal with this:
- Re-profile if you want to retain a very high level of accuracy.
- Ignore the whitepoint shift. As long as the shift isn’t too large and you don’t use absolute colorimetric intent, this will work fine.
That would assume that the whitepoint is the only thing that drifted, which is probably inaccurate – white is made out of a mixture of the primaries, so they have shifted as well. There’s two ways to deal with this:
- Re-profile if you want to retain a very high level of accuracy.
- Ignore the whitepoint shift. As long as the shift isn’t too large and you don’t use absolute colorimetric intent, this will work fine.
Florian,
what do you mean by “re-profile”?
Meaning a whole new calibration from scratch?
Calibration means using OSD and video card LUT to get closer to desired result.
Profiling means describing device behaviour – with or without calibration applied.
My question was about guessing new profile without changing LCD settings and it cannot be guessed with existing software so the new profile should be created (again, with ot without calibration).
