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Hello,
Thank you for DisplayCAL and this forum, on which I have learnt a lot about color management and screen calibration. But… I still lack of some understanding to be able to make it on my own.
I use an (old) macbook unibody (late 2008, 5.1 model), which has a “color widescreen LED-backlit TFT active-matrix “glossy” display”.
My OS is linuxmint 19, with displaycal 3.5 and Argyll CMS 2.0. I have just bought a spyder5 colorimeter. My goal is to have proper display, since my screen is rather bad and its contrast as well as its colors are obviously terrible. I want to use darktable to deal with some photos.
Here are five questions :
- Do you know which measurement mode I should select, probably between generic LCD and white LCD (the Spyder5 corrections are imported) ? I don’t know what is suited to my screen.
- Should I try to create a 3D LUT profile, or just an icc profile ? I understood that with an icc profile, you have only a “1D LUT” that let calibrate white and grey scale, but that doesn’t modify colors. My screen is not good, so it could be great if the calibration and profiling process could end with something better, even when I am not in darktable (which can use the icc profile to correct colors display). But probably there are some things I can not expect on a laptop screen.
- What kind of informations does the “verify” process bring on a newly produced profile ? Should I do that, as a beginner ?
- Do you know what I have to do with the produced profile to make it used by linux mint as a general profile ? (I don’t see any “profile” options on the display setting, nor on the nvidia graphic card settings)
- Have you some advice on some parameters to help me getting an acceptable result ?
Thanks for the help you could give,
Girafenaine
Hello,
I tried to calibrate and profile my screen. It seems to correct well the main color matters. I tried with “LCD (white LED)” and “LCD (generic)”. Results seems to be very near. In both cases, my screen faces some difficulties in the lower part of the greyscale, if I understand well the “verify” results, and a 7,18 deltaE.
- Here are attached two verification files, one for “white LED” profile, the other one for “generic” profile (and the corresponding icc files). Could you please have a look and tell me what I have to know about theses profiles, and if i could try some other parameters or processes to get good colors ?
- When I run “verify”, what do the results exactly mean ? Is it that the screen does not reach the icc profile aimed values ? I find it strange, because the icc profile is created especially in order to correct the screen behavior, with a RGB signal translated into the adequate light and color levels.
Girafenaine
Black is not corrected unless you ask for. Since you have a very very very low contrast, do not even try… so “don’t look” at black or near black results in validation.
Your extremely low contrast may be partially caused by whitepoint correction so chose the lesser evil: bluer/colder white and more contrast or D65 white with 100:1.
I’ll try to use native white in that screen, or if it has some ugly green or pink tint then try to use the closest cool “white” (daylight/blackbody 7000K or even more, measure your native white).Is it that the screen does not reach the icc profile aimed values ?
Not “aimed” but “measured” after calibration: that is what a profile stores. And yes, your display does not behave like those profile. Why? a) It cannot b) read blackpoint compensation documentation. Those profiles store near a*~ b* ~ 0, your display does not behave like that after calibration.
I find it strange, because the icc profile is created especially in order to correct the screen behavior, with a RGB signal translated into the adequate light and color levels.
No… it does not work in that way: a profile is made in order to capture actual screen behavior (usually after calibration), maybe with some idealization if you wish it. Then color management tries to do the best it can* to render colors from different color spaces into that display using profile information.
(*)From gamut plot from one of your profiles it means that even under idealized conditions of bitdepth precision it can only show about 6x% of sRGB.
Either the MacBook display has really aged badly, or you’re driving it with video levels and the display is expecting full range. This may be a configuration setting in the display driver somewhere (according to everymac.com, this MacBook has nVidia graphics, so if you’re using the binary nVidia driver it usually has a setting for output levels in its control panel.
Hello, thank you for your help.
Vincent : OK for your explanations. I understand that profile describes what the screen produces, but with a part of idealization, especially in the low lights as far as my screen is concerned. That why even with the profile installed, my screen is not able to render proper light levels, and of course a lot of saturated colors since this screen reaches only 60% of the sRGB space. I don’t know whether my screen modify the display only with the calibration data, or with the profiling data as well, or if the profiling data use is managed only by some applications (gimp and dartable for example).
Do you think a more contrasted display is more important that the color accuracy ? My main goal is to work on photos, thus I was thinking that a proper 6500K white was quite useful not to be upset when I will print some of my photos. I don’t know if contrast weakness on my screen can lead to some differences when I print photos. Do you have an advice about this point ?
Florian : I have nvidia driver indeed. I did not modify any RGB gain nor gamma with it (I thought it was better to let Displaycal alone to build a profile, even if there was a big blue hue I could correct with the nvidia driver settings). I was not able to find any “video levels”, and I don’t understand your “the display is expecting full range” sentence. Could you explain me with some details what I should check in the nvidia driver settings ?
Thanks again for Displaycal : even if my screen is far from ideal, the calibration-profiling process offered me proper colors, and since yesterday I am eager to manage and work on my photos (that were waiting for me for a long time).
Girafenaine
Do you think a more contrasted display is more important that the color accuracy ? My main goal is to work on photos, thus I was thinking that a proper 6500K white was quite useful not to be upset when I will print some of my photos. I don’t know if contrast weakness on my screen can lead to some differences when I print photos. Do you have an advice about this point ?
If gamut and constrast issues ar not caused by what Florian hints, then that display is not suitable for your task at its current state.
In that particular situation: very small gamut, very very very low contrast what you can do is to make that display more “useful” for everyday use: browsing and such. So in that particular situation I would choose more contrast than 100:1 going to native or near native white.
