robedge
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U2413 Calibration DisplayCal/ArgyllCMS MacOS

Hi, 
 

I have searched this community extensively and I must first of all say thank you to @yumichan for his incredible support throughout this forum. Clearly someone who knows what they are talking about. I just have a few questions related to comments made in past posts.

The first one from 2015 

"Apple is not a good choice for image or photo: OS limitations (no 10bit), plus hardware limitations (nvidia or intel GPUs), plus limited vendor support (dell)"

Is this still true @yumichan? How does Apple, specifically with OSX and Nividea graphics cards go about calibrating their own wide gamut displays? Is it an issue. e.g. How should I calibrate my MacBook's retina display? 

The second one is from the same thread in 2015

"Use NEC PA242W or Eizo CS240, you'll get LUT3D calibration capabilities under macOS".

Are we really this limited under macOS? How can I choose a display that can be calibrated properly under macOS? What the the technical specifications I should take care of? 

I am using the DispcalGUI/ArgyllCMS X-Rite i1Display Pro combination now, after following advice on here. I used a windows machine (7) to create my new ICM profile for the displays 3DLUT, which I applied and copied from the windows system to my mac system. (windows machine attached over DisplayPort. Mac attached over mini DisplayPort). I understand I need to manually copy (i.e. physically via the screen menu) over the Luminance and contrast settings after I make the switch from windows to mac. 

In DCCS, I have the option to calibrate CAL1/CAL2. The program allows me to choose the RGB primaries. How do I find (measure) the values for custom 2.2 Gamma instead. (since: sRGB gamma is not the same as "2.2 Gamma" as it is more for "entertainment", according to a comment from @yumichan).

For info: I am interested specifically in the sRGB range for photo editing. Does this mean I could calibrate in sRGB, or should I calibrate with wider RGB range, and then work (Lr, PS) in an sRGB environment. 

Here's a link to my measurement report

HTML Measurement Report

I would really appreciate some help/feedback here. There's so much to learn. 

Cheers in advance, 

 -Rob

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yumichan
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

So much time withut writing here...

OSX 10bit = yes, but you need newer models with AMD cards like iMac P3 5k or some of the new macbooks with radeons. These cards could perform even GPU (traditional "non hardware" calibration) without banding. Apple did the good move choosing AMD cards. Of course PC people have that since a lot of years ago.

AFAIK limited support from vendors is strill true. AFAIK U2413 HW cal with OSX DUCCS is not supported, only for newer models. Ask dell why.

If you want D65 white, sRGB gamut and 2.2 gamma then... just select "custom xy" in DUCCS, go to wikipedia, copy xy coordinates of sRGB primaries, select D65 white and 2.2 gamma.
Although LR and PS are color managed, LR/CamaraRaw "raw to color coordinates, then to display gamut" it's done at whatever gamut your display has in a given configuration (like CAL1/CAL2). This means that if you work in a RAW in LR with U2413 native gamut with lots of saturated color like flowers or some plastics, when you export to sRGB your image you may get some "changes".
If all your work is done in sRGB, just use some CAL1 calibrated to sRGB (or sRGB-like with 2.2 gamma) like I've explained and you'll get WYSIWYG.

Report is missing, 404 not found.

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robedge
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

Thanks a lot Yumichan, 

I think I've already come some way with my understanding since the original post. 

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 in detail exactly  what I’ve actually done.

I'm now calibrating and working (Lr ans PS) in an RGB (ProPhoto RGB) environment, right up until I export, where I convert and embedded the sRGB profile. 

For the entire procedure, I do:

  1. Run a measurement report on the monitor from my mac connected with miniDisplayPort. Extract the RGB xy coordinates from the generated html file.
  2. Switch to windows machine connected via DisplayPort and run/configure DELL sw for calibrating gamma, whitepoint, xy coords for gamut. (gamma 2.2, D65, 120cd/m2, custom RGB whitepoint). I save this to either CAL1 or CAL2.
  3. The output from DELL SW is a <name>.icm profile
  4. 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.
  5. I then set-up DisplayCal as images in dropbox link (3 of which) and click “Calibrate & Profile”.
  6. 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”.

DropBox Link

You'll see my measurement report for both monitors in that link too. 

Thanks again. I really appreciate the support. 

 

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yumichan
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

If you want native gamut, upgrade to DUCCS 1.6.5. We got an usable native preset at last.
No need to measure xy native coordinates. It is true native gamut, I've seen identity matrix on DUCCS log sent to my U2413.


One more thing, these dells have no LUT3D. They use LUT-matrix-LUT for calibration which is a cheaper calibration solution that allows gamut emulation like sRGB or AdobeRGB.
1st LUT "de encode" values from gramma encoded to linear, matrix make gamut emulation, 2nd LUT reencode values to a gamma and also makes gray calibration and whitepoint.
They are akin to CS series from Eizo, or the other ultralowcost widegamut monitors like the ones from HP, Benq and such manufacturers.
True LUT3Ds are found in NEC PAs and some higher end Eizo CG.

robedge
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

What does "Native Gamut" imply, Yumichan? 

Also, do you have any recommendations on further reading/learning re. colour calibration and management? Books, articles, courses? 

No LUT3D! Ah, very interesting. If I want to buy a new model of monitor, I guess I should look out for this. Is this even specified ? 

 

EDIT: It is specified. I just looked: "14-bit 3D internal programmable lookup tables (LUTs) for calibration" for the PA272W, for example. Noe the next q is, can I calibrate this on a newer model mac...and does the calibration SW come from NEC? 

 

 - Rob

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yumichan
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

Native gamut means that you use full gamut from your monitor, without limiting it to sRGB or AdobeRGB.
How you can limit one monitor's gamut? with a LUT3D or lut-matrix like our dell.
How? For our Dells each "emulated gamut primaries" like sRGB R,G&B primaries is a linear combination of native R,G&B. I mean sRGB Red "255" after calibration to sRGB is actually build with a portion or "true"/native blue, green and red in different quantity. Same for sRGB emulated geen and blue.
3 native combination for 3 emulated primaries = 3x3 matrix.
Native gamut is identity matrix since no other color gets mixed up.

... and DUCCS 1.6.5 has at last native gamut preset with custom gamma and custom whitepoint.

For photo editing LUT3D is not really needed. LUT3Ds are useful to emulate other screens or to a finer calibration in non color managed enviroments like video edition.

NEC has support for Macs sinec long time ago, but NEC calibration software is not free. You have to pay it. It's called SpectraviewII and some models(-SV2) have this software bundled (with the software cost applied to its price).

Your reports seem to be fine. If your displays have a "sufficient" color uniformity no need to change them.

 

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robedge
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Re: U2413 Calibration DisplayCal/ArgyllCMS MacOS

Hi Yumichan, 

Thanks a lot. I'm not planning on changing them, it's just I want to understand exactly what I'm doing. I'm an engineer, is't hard-coded into all of us. You've already helped me to come much further with my understanding, I appreciate that! 

- Rob

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