Wide Gamut Display

[bluefightingcat]

I'm still looking for a new display and was considering the Dell U2711 which is a Wide Gamut Display. I've found warnings around that Wide Gamut displays can cause things to look over-saturated with non-color managed software. Since I still don't understand color-management fully I have a couple of questions maybe somebody can help me with.

1. ASP will not be a problem since this is color-managed. I just have to load the displays ICC profile and it should work correctly. Right? I will use DispcalGUI (argyll CMS) to calibrate and make a profile for the display.
2. If I use DispcalGUI I can make Linux load my display's ICC profile so that my whole OS is color managed? Right?
3. If the answer to 2 is no...then can I simply put the display in sRGB mode to avoid oversaturation problems with non-colored managed stuff? I can then always move to wide gamut mode when editing photos.
4. Can I export my photos from ASP in sRGB (or any other color space I choose)? Is this the same as adding some sort of color management tag to the photo/metadata?
5. As far I as I have understood Google Chrome (which is my main browser) is color managed. That means that both I and everyone else should see the photos approx how I would want them so see them assuming their displays are not completely and hopelessly uncalibrated.
6. Is this all too complicated and am I causing myself extra hassles? Should I just go for the Dell U2713 which is just 100% sRGB?

Any help would be much appreciated.

BFC

[afx]

1. ASP will not be a problem since this is color-managed. I just have to load the displays ICC profile and it should work correctly. Right? I will use DispcalGUI (argyll CMS) to calibrate and make a profile for the display.

Yes.

2. If I use DispcalGUI I can make Linux load my display's ICC profile so that my whole OS is color managed? Right?

No.
Your screen is calibrated. Any app that wants to display accurate color still needs to load the profile to know about the current display characteristics.

3. If the answer to 2 is no...then can I simply put the display in sRGB mode to avoid oversaturation problems with non-colored managed stuff? I can then always move to wide gamut mode when editing photos.

You could, but that sucks major.
Use color managed browsers like firefox or the latest chrome.
Use image viewers like EOG that are color managed.

4. Can I export my photos from ASP in sRGB (or any other color space I choose)? Is this the same as adding some sort of color management tag to the photo/metadata?

You actually convert it from the internal AS working space (Linear ProPhoto) to the destination space in the queue and you can optionally add the profile.
It is of course best practices to convert everything meant for mass consumption to sRGB and tag it as such.

5. As far I as I have understood Google Chrome (which is my main browser) is color managed. That means that both I and everyone else should see the photos approx how I would want them so see them assuming their displays are not completely and hopelessly uncalibrated.

That is a bit optimistic. Most peoples displays are set too bright.
Most Linux users use Chromium, not chrome. At least on my Ubuntu 12.4 box this sis still not color managed (in contrast to the current Google Chrome browser).

But, taking all things into account, this still produces more accurate results than working on an uncalibrated sRGB screen.
You might want to follow the sRGB link in my signature.

6. Is this all too complicated and am I causing myself extra hassles? Should I just go for the Dell U2713 which is just 100% sRGB?

If you only aim for web output...
As soon as you are interested in more accurate colors for yourself or for printing, then a wide gamut screen is preferred.
And you still need to calibrate it, no matter what the native gamut of the screen is.

cheers
afx

[bluefightingcat]

Thanks AFX for once again clearing things up.

I currently use Chrome v22 on my Chakra Linux box. Don't know how they got Chrome on it but it is different from chromium.

So I have ASP, GIMP and Digikam and Chrome all of which are color managed. So I think I'm good to go?

I think in the end I will go for the U2711.

BFC

[afx]

I currently use Chrome v22 on my Chakra Linux box. Don't know how they got Chrome on it but it is different from chromium.

I use a PPA to get Chrome on Ubuntu. Many ways to get it

So I have ASP, GIMP and Digikam and Chrome all of which are color managed. So I think I'm good to go?

Sounds good.

Make sure your ArgyllCMS and DispCalGUI are current, some distros are a bit behind.

cheers
afx
(I have a wide gamut Linux laptop (T520 with the highres screen) and sRGB screen on my windows box...)

[bluefightingcat]

Hi AFX,

I have one more question regarding color management

2. If I use DispcalGUI I can make Linux load my display's ICC profile so that my whole OS is color managed? Right?
No.
Your screen is calibrated. Any app that wants to display accurate color still needs to load the profile to know about the current display characteristics.

In DispcalGUI you have the option to automatically load your display profile when you boot up your computer. Wouldn't this mean that everything in the OS is being showed accurately according to your display profile?

BFC

[afx]

In DispcalGUI you have the option to automatically load your display profile when you boot up your computer. Wouldn't this mean that everything in the OS is being showed accurately according to your display profile?

A display profile usually has two parts. A LUT part and a profile.
A LUT table that tells the video card how to achieve the desired display characteristics (or at least get as close as possible). This is what you send to the X server with the help of DispCalGUI or the Gnome Color Manager (or dispwin from Argyll).
But that just tweaks the display. Applications still need to know about current characteristics.
This is where the profile part comes in that describes the screen characteristics that are in effect when the LUT is loaded. This profile is used by applications to display colors as accurately as possible on the calibrated screen.
Depending on the application you will either have to explicitly load the profile (AfterShot) or it will be loaded automatically (Eye of Gnome).

Your application will need to know what the screen colors are, that is why it needs to load the profile. Otherwise it will have no reference point...

cheers
afx

[Brainslug]

Greetings all,
I also have a few questions about wide gamut displays and maybe someone here can answer them for me.

I am thinking about getting me a wide gamut display to connect to my Dell M4800, and the most attractive display from a pricing perspective is the Dell U2713H. I understand it supports hardware calibration (14bit LUT), but only when using the ridiculously expensive X-rite i1 Pro spectrometer and Dell's Windows software. Two show stoppers, as my budget is limited and I'm on Debian Linux.

The question now is will I be able to benefit from this monitor by just using the factory calibration, or will I be limited to a point where it's not worth buying a wide gamut display?
Also, I think I will still need an icc profile to load in ASP, and I am not sure if Dell ships one with the monitor or just programs the internal LUT as part of their calibration process.

Can anyone comment on this?

Thanks much!

[afx]

I am thinking about getting me a wide gamut display to connect to my Dell M4800, and the most attractive display from a pricing perspective is the Dell U2713H.

You might want to read the Prad review: http://www.prad.de/en/monitore/review/2 ... 2713h.html

I understand it supports hardware calibration (14bit LUT), but only when using the ridiculously expensive X-rite i1 Pro spectrometer and Dell's Windows software. Two show stoppers, as my budget is limited and I'm on Debian Linux.

While the Windows limitation sucks, me thinks the price performance ratio of the i1Display Pro is top.
Best colorimeter you can get apart from the Discus which would cost several times the money of the i1Display pro. And in contrast to previous generations, it does not have organic filters, so it will stay stable for many years to come.
You might save some pennies by buying the castrated version (slowed down in firmware) sold under the name ColorMunki Smile. It works with ArgyllCMS so you should be fine on Linux.

The question now is will I be able to benefit from this monitor by just using the factory calibration, or will I be limited to a point where it's not worth buying a wide gamut display?

Wide gamut and hardware calibration are not linked.

But, if you carefully read the Prad review, you will find that Dell botched the calibration part. If I remember correctly, the uniformity correction will not work when using custom calibration.
And any screen in the 27" class desperately need uniformitiy correction, otherwise it is unevenly lit.
(The Dell 2713H and the LG 27ea83 where on my shortlist a year ago, but the test results show that both have issues in the uniformity department that I consider in-acceptable, so I ended up with a PA series NEC instead (got the 30" for the street price of the 27" which made it even sweeter)

What would be the big advantage of hardware calibration?
You do not loose any bits in the pipeline for correcting issues in the screen, so the chances of banding are reduced. All corrections happen in the monitor, not the graphics card LUT.
So if you work with the native gamut of a screen and the screen is decent, you will not gain much by hardware calibration.
HW calibration has some other advantages, but they are more handling related...

So if there are no big deviations for the intended calibration target (which should be native gamut, gamma 2.2 and a decent luminance in the 100-120cd range) there will not be much changes due to the calibration part.

Also, I think I will still need an icc profile to load in ASP, and I am not sure if Dell ships one with the monitor or just programs the internal LUT as part of their calibration process.

I think Dell ships a profile. But that is useless.
A profile is only valid for the settings of the screen it was made under. As soon as you change the brightness (which is shipped way to high anyway), the profile will no longer describe the screen accurately. And screens do have variances.
So you will need the profile your screen anyway.

And from reading your post, I think you get calibration and profiling mixed up.
Calibration is the process of bringing the display in a defined state, potentially with a LUT adjustment.
After a display has been brought into a defined state, the exact response of the display is measured and put into the profile so that CM aware applications can learn about the display response and adjust the output accordingly.
So a profile has two parts, the calibration data to bring the screen into a defined state and the profile part to describe the display after the calibration has been applied.

cheers
afx

[brucet]

I would just like to add my 2 cents worth!!
Get the best you can with calibration. It's worth it. BUT do not go crazy trying to squeeze it to perfection. There is no 'perfection'. There are so many variables to colour. Monitor. Print paper. Display. Every one of these vary to some degree. I have my monitor calibrated the best I could achieve. Yet, depending on time of day, my monitor will give different results. So unless you work in a controlled dark room what you see will always be changing. I use profiles to print. Yet they also change depending on light conditions. After you finally get your work onto paper where it is displayed will change everything once again.

My point being that calibration and using profiles is worth some effort. But just remember that there are factors that will derail your best efforts that are out of your control. I 'try' to control as much as I can by only doing final work at a set time of day in deal lighting conditions.

regards

[Brainslug]

Hi afx,

thanks for the quick reply.

You might want to read the Prad review: http://www.prad.de/en/monitore/review/2 ... 2713h.html

Thanks for the link, that's a lot of good information.

While the Windows limitation sucks, me thinks the price performance ratio of the i1Display Pro is top.
Best colorimeter you can get apart from the Discus which would cost several times the money of the i1Display pro. And in contrast to previous generations, it does not have organic filters, so it will stay stable for many years to come.
You might save some pennies by buying the castrated version (slowed down in firmware) sold under the name ColorMunki Smile. It works with ArgyllCMS so you should be fine on Linux.

Actually, I do have a ColorMunki Smile which I've been using in combination with ArgyllCMS to profile my laptop displays until now. However, from reading through the ArgyllCMS mailing lists, it appears that the Smile is not capable of properly calibrating a wide gamut display, as it is "just" a calorimeter and not a full-blown spectrometer. (http://www.argyllcms.com/doc/WideGamutColmters.html) However, doing some more research on the i1DisplayPro, it appears that it's not really a spectrometer either, but just an "enhanced" calorimeter?!

But, if you carefully read the Prad review, you will find that Dell botched the calibration part. If I remember correctly, the uniformity correction will not work when using custom calibration.
And any screen in the 27" class desperately need uniformitiy correction, otherwise it is unevenly lit.

ArgyllCMS allows one to do uniformity correction. I did not realize that this can not be applied to the U2713H. Thanks for pointing this out.

What would be the big advantage of hardware calibration?
You do not loose any bits in the pipeline for correcting issues in the screen, so the chances of banding are reduced. All corrections happen in the monitor, not the graphics card LUT.
So if you work with the native gamut of a screen and the screen is decent, you will not gain much by hardware calibration.
HW calibration has some other advantages, but they are more handling related...
So if there are no big deviations for the intended calibration target (which should be native gamut, gamma 2.2 and a decent luminance in the 100-120cd range) there will not be much changes due to the calibration part.

That basically answers my biggest question.

And from reading your post, I think you get calibration and profiling mixed up.

I am absolutely sure I did, because I'm still not 100% sure what hardware calibration exactly includes. Is it just adjusting brightness and whitepoint? If so, why would a 14bit LUT be necessary for this rather simple task?

So a profile has two parts, the calibration data to bring the screen into a defined state and the profile part to describe the display after the calibration has been applied.

That's where the confusing part lies in. The profile is basically a .icc file on my computer, right? So if the calibration data is part of this (software) profile, then why would I need hardware calibration? I was under the impression that the 14bit hardware LUT of the monitor would basically take care of everything and not require an icc profile anymore, but this assumption is obviously wrong. I just haven't figured it quite out then.

Thanks for all your help!

[Brainslug]

I would just like to add my 2 cents worth!!
Get the best you can with calibration. It's worth it. BUT do not go crazy trying to squeeze it to perfection. There is no 'perfection'. There are so many variables to colour. Monitor. Print paper. Display. Every one of these vary to some degree. I have my monitor calibrated the best I could achieve. Yet, depending on time of day, my monitor will give different results. So unless you work in a controlled dark room what you see will always be changing. I use profiles to print. Yet they also change depending on light conditions. After you finally get your work onto paper where it is displayed will change everything once again.

My point being that calibration and using profiles is worth some effort. But just remember that there are factors that will derail your best efforts that are out of your control. I 'try' to control as much as I can by only doing final work at a set time of day in deal lighting conditions.

regards

Hi Bruce,

thanks for the input. I understand that there is a limit of what can be achieved here, and since I do not make a living out of my photography (as you can easily tell by the amateur questions I'm asking), that is not my goal. I am more trying to understand a couple of basics, which are very confusing to me at this point. I was actually just looking for a new monitor - but reading one review and comment usually leads to another one, and another, and so on; and by the end of the day I was quite confused and I would like to at least understand a couple of things before spending big bucks on a new toy that I don't fully understand. That's why I appreciate all the info I've been getting on this board so far.

Cheers!

[afx]

You might save some pennies by buying the castrated version (slowed down in firmware) sold under the name ColorMunki Smile. It works with ArgyllCMS so you should be fine on Linux.

Actually, I do have a ColorMunki Smile which I've been using in combination with ArgyllCMS to profile my laptop displays until now. However, from reading through the ArgyllCMS mailing lists, it appears that the Smile is not capable of properly calibrating a wide gamut display, as it is "just" a calorimeter and not a full-blown spectrometer. (http://www.argyllcms.com/doc/WideGamutColmters.html) However, doing some more research on the i1DisplayPro, it appears that it's not really a spectrometer either, but just an "enhanced" calorimeter?![/quote]
Sorry, I mixed them up. The ColorMunki Display is the castrated i1Dsiplay Pro,
The Smile is just the old i1 Dislay2, which is not only unsuitably for wide gamut displays but lso has a wide product variance.

ArgyllCMS allows one to do uniformity correction. I did not realize that this can not be applied to the U2713H. Thanks for pointing this out.

What make you think that?
Uniformity correction can only be done in the display hardware if the hardware supports it.

And from reading your post, I think you get calibration and profiling mixed up.

I am absolutely sure I did, because I'm still not 100% sure what hardware calibration exactly includes. Is it just adjusting brightness and whitepoint? If so, why would a 14bit LUT be necessary for this rather simple task?

Hardware calibration means the display LUT is used to adjust the display response. The bigger the LUT, the finer the adjustments that can be made.
And you hopefully never adjust brightness via the LUT, that should be done via the backlight.
The display response is not only white point and gamma, it is the response over the whole spectrum that is adjusted.

So a profile has two parts, the calibration data to bring the screen into a defined state and the profile part to describe the display after the calibration has been applied.

That's where the confusing part lies in. The profile is basically a .icc file on my computer, right? So if the calibration data is part of this (software) profile, then why would I need hardware calibration? I was under the impression that the 14bit hardware LUT of the monitor would basically take care of everything and not require an icc profile anymore, but this assumption is obviously wrong. I just haven't figured it quite out then.

Well, the difference between HW and SW calibration is where and how the calibration part of the ICC profile is applied. With HW calibration it is loaded into te monitor, wit SW calibration it is loaded into the graphics card.
And, with a hardware calibrated screen, the ICC file might not even have calibration data but only profile data, but that really depends on the actual system used.

cheers
afx

[brucet]

Brainslug I have no issues with 'learning'. I've spent hours working on calibration and profiles. Only to be outsmarted by stuff I couldn't control. Calibration and profiles are essential. As long as those who seek perfection realise that it don't exist. Understanding what you have and what the limits are is the key.

With my work with clients I often appear to have on screen gamut issues only to find that at print time they don't exist!!! (Paint work on vehicles often tests the limits of gamut.

regards

http://www.cre8ivephotography.com/

[Brainslug]

I got a really good deal on the U2713H, so it is standing on my desk right now (rev.A06)
After playing around for a while with the monitor settings, ArgyllCMS and my ColorMunki Smile, I think I now actually got the idea of what this whole hardware calibration thingy is all about. And I think I now understand most of the concepts that were confusing in the beginning. Good.

But wait, now there's new confusion...
From the post on the Argyll website about wide gamut displays (http://www.argyllcms.com/doc/WideGamutColmters.html) I understand that technically a spectrophotometer is required to calibrate a wide gamut display. However, it seems to be an option to use a colorimeter, when correcting for its shortcomings by applying a calorimeter calibration spectral sampe (CCSS) file. The i1 Display Pro that Dell recommends is a colorimeter, and dispcal seems to be offering CCSS files for the U2713H (http://dispcalgui.hoech.net/colorimeter ... LCD&html=1). So technically, if I get me a i1 Display Pro, all I need to do is upload that CCSS file to the i1 via dispcalGUI, and I should be able to calibrate/profile the U2713H decently.

First question: is this correct, or am I missing something?
Second question: there seem to be two CCSS files, one for sRGB and one for AdobeRGB on dispcalgui's website. Why? Which one would I use, because I don't see any option in dispcalGUI to select either one.?

As usual, thanks much for any advice!

[afx]

From the post on the Argyll website about wide gamut displays (http://www.argyllcms.com/doc/WideGamutColmters.html) I understand that technically a spectrophotometer is required to calibrate a wide gamut display. However, it seems to be an option to use a colorimeter, when correcting for its shortcomings by applying a calorimeter calibration spectral sampe (CCSS) file.

It is not just the gamut, but also the backlight type (CCFL vs the various LED types) for which adjustment files are needed.

The i1 Display Pro that Dell recommends is a colorimeter, and dispcal seems to be offering CCSS files for the U2713H (http://dispcalgui.hoech.net/colorimeter ... LCD&html=1). So technically, if I get me a i1 Display Pro, all I need to do is upload that CCSS file to the i1 via dispcalGUI, and I should be able to calibrate/profile the U2713H decently.

I thought the adjustment files are part of ArgyllCMS, but I might be wrong (just hazy memory from following the mailing list).

Second question: there seem to be two CCSS files, one for sRGB and one for AdobeRGB on dispcalgui's website. Why? Which one would I use, because I don't see any option in dispcalGUI to select either one.?

Hmm, I would think the AdobeRGB one if you want to use the display in full gamut.
But I must admit I never looked in detail at using the i1DsipalyPro with ArgyllCMS as I have a spectrometer. (I did some comparisons of my ColorMunki with the i1Display Pro on my NEC with the SpectraView Software as the i1DisplayPro is supposed to be even better than the ColorMunki Spectro for displays but could not see any real difference and the de numbers where quite similar)

cheers
afx