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Hi all,
I have so many general questions which I need to help me really understand this tool, and calibration/profiling in general, that I’m just going to dump them here with the hope I get some answers:
Let me first start off by explaining a bit what I hope to achieve and what HW/SW I’m using. I’m an engineer/photographer, hoping to achieve the best colour accuracy in my images by working in a calibrated, profiled and colour managed environment. I predominately export for Web Viewing/digital Viewing only, so mostly sRGB space, and sometimes for print. I work with Mac, X-Rite i1 Pro, Lr, PS, DisplayCal and ArgyllCMS.
- It’s pretty well known that Mac’s aren’t very good for calibrating Wide-Gamut displays, due to the whole 8bit vs 10bit story, but if this is the case, how do they calibrate their own wide-gamut display’s?
- I’ve recently calibrated by own wide-gamut display (DELL’s U2413) which I had to use a Windows machine for, running the DCCS software from DELL. For the RGB values I decided to manually enter them into the DCCS SW for calibrating the displays 3DLUT to CAL2. For this, I took a DisplayCal html measurement report, selected xyZ from the drop-down and took a note of the measured X and Y values for RG and B. I did this after reading how to do it on another forum, but I’m not quite sure what I’ve actually done. Could someone here explain this process in more detail to me?
- If I purchased another monitor, say an LG for arguments sake, how would I go about calibrating it’s 3DLUT table. Do I need factory SW (like the DCCS from DELL) or can this be done via DisplayCal?
- If my ultimate goal is to export image files in the sRGB colour space, can I (should I) calibrate/profile the monitors in RGB or sRGB. I created my own colour profile by measurement, as explained in point 2 above, what have I actually done in terms of colour space, is this correct? i.e. what colour space have I actually calibrated too?
- Can I post my calibration/profiling flow and html report for review by someone? (html attached anyway, as it might help)
- How can I relaunch the data and plots generated by ArgyllCMS software at the end of the profiling phase by DisplayCal?
- Why is MacOS limiting the LUT’s to 8-bit? Is this even still true?
- What is the x axis on the DisplayCal html report?
I have more questions, but that’ll do for now. Thanks in advance for the support.
– Rob
Hi,
- It’s pretty well known that Mac’s aren’t very good for calibrating Wide-Gamut displays, due to the whole 8bit vs 10bit story
that sounds like an anecdote. My own mac mini (2011 model) with High Sierra seems to apply dithering, so gradients are smooth even over an 8-bit HDMI connection to a wide-gamut display.
2. […]
I have no experience with Dell displays, but it sounds like your goal was to calibrate to custom xy chromaticity coordinates (or only whitepoint) using the vendor software? Someone else will have to comment.
3. If I purchased another monitor, say an LG for arguments sake, how would I go about calibrating it’s 3DLUT table. Do I need factory SW (like the DCCS from DELL) or can this be done via DisplayCal?
DisplayCAL does not directly support hardware LUTs in monitors.
4. If my ultimate goal is to export image files in the sRGB colour space, can I (should I) calibrate/profile the monitors in RGB or sRGB.
Limiting the monitor to sRGB before profiling it is usually not a good idea as it unneccesarily restricts the gamut that the profiler sees, and may introduce artifacts through the monitor’s internal processing.
5. Can I post my calibration/profiling flow and html report for review by someone? (html attached anyway, as it might help)
Sure.
6. How can I relaunch the data and plots generated by ArgyllCMS software at the end of the profiling phase by DisplayCal?
The reports are just HTML files saved on your computer. See the documentation for the default location.
7. Why is MacOS limiting the LUT’s to 8-bit? Is this even still true?
I’m not sure if it is. Even if it is, dithering seems to mitigate the problem in a way that should make it a non-issue.
8. What is the x axis on the DisplayCal html report?
Signal (R=G=B) as percentage.
Hoi Florian,
Vielen Dank für die Info! Es hat schon etwas geholfen, aber lieder habe ich immer noch ein paar Fragen: (Sieh BOLD font unten)
It’s pretty well known that Mac’s aren’t very good for calibrating Wide-Gamut displays, due to the whole 8bit vs 10bit story
that sounds like an anecdote. My own mac mini (2011 model) with High Sierra seems to apply dithering, so gradients are smooth even over an 8-bit HDMI connection to a wide-gamut display.Which monitor are you using? Are you calibrating the monitor’s LUT and how are you doing that? Dedicated SW from manufacturer?
2. […]
I have no experience with Dell displays, but it sounds like your goal was to calibrate to custom xy chromaticity coordinates (or only whitepoint) using the vendor software? Someone else will have to comment.Yes, something like that. I was definitely using the vendor SW, basically because it’s the ONLY option I have to calibrate the displays LUT. I read on a forum, that I should use DisplayCal to first measure the RGB values in xyZ coordinates, and use those values for calibrating, rather than using the default colourspace options (e.g. RGB, or sRGB) in the tool.
for eg. I use DisplayCal and ran a measurement, found Red in the list, (255, 0, 0), read out the measured XY value and used this number for R, XY values in the vendor SW. Same for GB.
3. If I purchased another monitor, say an LG for arguments sake, how would I go about calibrating it’s 3DLUT table. Do I need factory SW (like the DCCS from DELL) or can this be done via DisplayCal?
DisplayCAL does not directly support hardware LUTs in monitors.Does every monitor come with vendor SW to actually calibrate the displays LUT then? This is what’s confusing me. For example: how do I calibrate an iMac? I mean actually calibrate, not profile. I haven’t been able to find this information on other forums.
4. If my ultimate goal is to export image files in the sRGB colour space, can I (should I) calibrate/profile the monitors in RGB or sRGB.
Limiting the monitor to sRGB before profiling it is usually not a good idea as it unneccesarily restricts the gamut that the profiler sees, and may introduce artifacts through the monitor’s internal processing.OK, got it!
5. Can I post my calibration/profiling flow and html report for review by someone? (html attached anyway, as it might help)
Sure.Ok, I’ll work on it this weekend. Screen shots etc. Would be extremely helpful for me. Thanks. Any comments on the measurement reports already submitted? Look ok?
6. How can I relaunch the data and plots generated by ArgyllCMS software at the end of the profiling phase by DisplayCal?
The reports are just HTML files saved on your computer. See the documentation for the default location.I’m not referring to the HTML reports, but rather the report generated just after profiling has finished. The plots *and* text generated by ArgyllCMS (I think). It automatically pops up, just after profiling and I would like to see all of the information again…specifically the text information and the 3D gamma space.
7. Why is MacOS limiting the LUT’s to 8-bit? Is this even still true?
I’m not sure if it is. Even if it is, dithering seems to mitigate the problem in a way that should make it a non-issue.Ok, interesting.
8. What is the x axis on the DisplayCal html report?
Signal (R=G=B) as percentage.Cheers.
2- Current widegamut LED displays have a native gamut larger than sRGB or AdobeRGB.
If vendor HW cal software does not have a Native preset with custom whitepoint, gamma.. etc but it has a “custom gamut emulation” where you put R, G and B emulated coordinates, the, yes… you should use that custom gamut options if you want native gamut and whatever calibration target (white, gamma etc…)
If you want sRGB gamut with other than D65 white and “sRGB” preset does not have custom whitepoint, then you need to use “fully customized” calibration.
Presets are presets, as long as they fit your needs are fine. When you need something not covered by them use customized setup if avaliable.3-AFAIK iMac displays are akin to laptop displays when you calibrate them: Whitepoint correction is done at GPU level, so better not moving too far away from native gamut. Brightness is the only control, like laptops.
Since you chose LG as an example:
LG widegamuts have their own software to write monitor luts but their software lacks of GB-LED spectral correction. They rely on RGBLED spectral correction which was used by some old model from HP, that RGBLED backlight is no longer used in newer models. Your GB-LED Dell uses LG panels so this should be the spectal correction used in LG software for your Widegamut LED equivalent in LG, but they don’t use the good one.Newer Widegamut LEDs like UP Dells or CG Eizos (bigger P3 gamut coverage) use a diferent backlight from these two (red channel spectrum has several spikes in red wavelengths) but GB-LED spectral correction seems to be a good match because i1DisplayPro sensivity curves (stored in firmware) seem to be very close to CIE 1931 2º observer across “red range”.
Error caused by choosing RGBLED correction instead of the proper one (GB-LED or the newer one) depends on actual i1DisplayPro sensivity curves and firmware sensivity curves. The closer they are for your particular unit to standard observer (and between them), the lower errors will be. In RGBLED correction red channel has a very very narrow and high spike so it is plausible to think that any difference between your particular i1DisplayPro and standard observer in this very narrow wavelength range will be magnified much more than in other scenarios (the “good” spectral corrections).
Newer P3 iMacs use a backlight close to that new widegamut LED from UP Dells or CG Eizos but more limited in green channel. Users reported that GB-LED (RGphosphor) work fine with i1DisplayPro and P3 iMac
AFAIK only NEC, Dell, Viewsonic, Wacom and HP use “the good” spectral corrections for widegmut led in software avaliable to calibrate their displays LUT.
Eizo is a “blacker” box than usual so who knows, Asus seems to do not use them at all and the others use that forgotten RGBLED correction (they seems to use an 7year old outdated i1DisplayPro SDK without the newer corrections for widegamut LEDs, Why? INDK…).Calibrite Display Pro HL on Amazon
Disclosure: As an Amazon Associate I earn from qualifying purchases.Thanks, Vincent! Really appreciate the help.
I’m going to post my calibration workflow etc soon. Hopefully I’m on the right track.
If the DisplayCal doesn’t calibrate monitors LUT’s, then I’m still a little confused what this option in the DisplayCal does. i.e. are there advantages for my application in running it? Like I mention, I want accurate colour reproduction for editing photo’s in LR. I predominantly export in sRGB for web viewing or digital viewing.
– Rob
Monitor LUTs allows you to calibrate that screen like a “black box” device to a desired target: whitepoint, gamma and grey without “color”.
A little more advanced monitor LUTs allows you to calibrate your monitor to a smaller colorspace than its native gamut (sRGB for example).
The hardware inside your Dell (LUTs) allows you to do these two types of calibration.
Dell’s calibration software measures uncalibrated monitor, calculates those LUT and upload them to the monitor. It is not very good doing this task but it does it.DisplayCAL and other calibration software allows you to calibrate whitepoint, gamma and neutral greyscale with the help of LUTs located inside graphics card. That LUT contents are stored in ICM profile in a special tag called VCGT.
When you set a DisplayCAL’s profile as default display profile, that calibration is loaded (with the help of DisplayCAL tray icon for some OSes).So you can use just Dell’s software for this task, just DisplayCAL or Dell’s software and then DisplayCAL if Dell’s software didn’t fix all things to be fixed.
Dell’s software is hardware calibration (writes monitor LUTs) so you won’t be limited by “banding” (“steps” in gradients) caused by some graphcis cards.
The easy way:
If you just want sRGB with its default D65 white, use Dell software and configure it to sRGB preset and set ICC version = 2 for profile creation. Then run a verification report for that profile with DisplayCAL and RGphosphor correction (GBLED). If DisplayCAL report it is good then you are done.
If it is not as good as it should be because you do not want as target what dell’s team called “sRGB preset” (for example 2.2 gamma), then use full custom mode in Dell software and set the values that you want (gamma, whitepoint, xy coords for gamut…)
If it is not as good as it should be because Dell’s software computed calibration is not as good it should be, you may try to correct whitepoint, gamma and grey neutrality with DisplayCAL.
If you do not want to use Dell’s software or if it hangs while calibrating or if there is no version for your OS, then just use DisplayCAL.
Very helpful, cheers Vincent!
For the procedure, I do pretty much that:
- Run a measurement report on the monitor from my mac connected with miniDisplayPort. Extract the RGB xy coordinates from the generated html file.
- Switch to windows machine connected via DisplayPort and run/configure DELL sw for calibrating gamma, whitepoint, xy coords for gamut, like you said. (gamma 2.2, D65, 120cd/m2, custom RGB whitepoint). I save this to either CAL1 or CAL2.
- The output from DELL SW is a <name>.icm profile, again, as you said.
- I then copy this file from the windows directory to my mac (library –> ColorSync–>Profiles), and apply the profile (preferences –> display –> colour) *before* opening DisplayCal.
- I then set-up DisplayCal as per attached screen shots (3 of which) and click “Calibrate & Profile”.
- After the process has completed, I then go to the Verification tab and click “Measurement report, making sure “Extended verification test chart” is selected from the drop down menu of “Test chart or reference”.
