Pages: [1] 2   Go Down

Author Topic: i1Profiler 1.2.0 sRGB bug?  (Read 10141 times)

colrook

  • Newbie
  • *
  • Offline Offline
  • Posts: 2
i1Profiler 1.2.0 sRGB bug?
« on: February 10, 2012, 05:54:13 pm »

Hey there,

just playing arround with i1Profiler, but there seems to be something strange, would be very nice if someone could confirm this behaviour or bug, to check if there is a problem on my end..
I try to calibrate with standard settings (D65, flare off, ambient light off, ADC off, Bradford, ICC v2, Matrix based ) but with "sRGB" tonal response curve instead of gamma 2.2!
With gamma 2.2 everything works fine, but as soon as I use sRGB at the end of the measurement the screen keeps white and nothing happens anymore  :'(
Tried with i1Profiler 1.2.0 on a Win 7 x64 machine with i1Display pro.

Do you experience the same problem?
Thanks in advance!
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #1 on: February 10, 2012, 06:31:00 pm »

I have no idea why they have an sRGB setting (or why you’d use it) when 2.2 is available. Just use 2.2.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WayneLarmon

  • Full Member
  • ***
  • Offline Offline
  • Posts: 162
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #2 on: February 10, 2012, 09:14:36 pm »

Quote
I have no idea why they have an sRGB setting (or why you’d use it) when 2.2 is available.

According to Wikipedia

sRGB also defines a nonlinear transformation between the intensity of these primaries and the actual number stored. The curve is similar to the gamma response of a CRT display. It is more important to replicate this curve than the primaries to get correct display of an sRGB image. This nonlinear conversion means that sRGB is a reasonably efficient use of the values in an integer-based image file to display human-discernible light levels.

and

It is often casually stated that the decoding gamma for sRGB data is 2.2, yet the above transform shows an exponent of 2.4. This is because the net effect of the piecewise decomposition is necessarily a changing instantaneous gamma at each point in the range: it goes from gamma=1 at zero to a gamma of 2.4 at maximum intensity with a median value being close to 2.2. The transformation was designed to approximate a gamma of about 2.2, but with a linear portion near zero to avoid having an infinite slope at K = 0, which can cause numerical problems.   (This is surrounded by lots of complicated formulas.)
http://en.wikipedia.org/wiki/SRGB

Doesn't this mean that gamma 2.2 is wrong for sRGB?

When I dumped an sRGB profile with an sRGB curve that was generated by SpectraView II with Argyll iccdump, the TRC values are lookup tables and not gamma curve specifications.  A sRGB profile with gamma 2.2 had "Curve is gamma of 2.199219" for the TRCs.

And FWIW, I have the same problem with iProfiler: when I select the sRGB curve, it hangs at the final white screen.  Also using i1 Display Pro on 64 bit Win 7.  Gamma 2.2 works.  I've been shrugging my shoulders at this, because my main monitor is a PA241W.  I only use iProfiler on my secondary monitors so they sort of match the PA monitor when I slide Explorer windows around.

Wayne
Logged

colrook

  • Newbie
  • *
  • Offline Offline
  • Posts: 2
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #3 on: February 11, 2012, 03:46:56 am »

Thanks for your fast replies guys :D
I thought sRGB would be a tiny little bit more exact for viewing sRGB content (I do mainly 3D rendering) but I maybe wrong here?!
Also thanks to Wayne for confirming that this is a plain software bug. Hope x-rite fixes this with next release.
Logged

jrp

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 322
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #4 on: February 11, 2012, 07:43:58 am »

Tried with i1Profiler 1.2.0 on a Win 7 x64 machine with i1Display pro.

Do you experience the same problem?

Yes, I've also had this.  I prefer to use Basiccolor and ArgyleCMS (but stick with 2.2 gamma anyway).
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #5 on: February 11, 2012, 11:24:08 am »

According to Wikipedia

This does not change my two questions.

There is no reason to select sRGB, especially if you hit what is a bug in the software.

The sRGB color space is theoretical, based on a CRT with specific phosphors circa 1993. I kind of doubt you are either using such a display and question why anyone would need to mimic that. In an ICC aware application, the TRC gamma isn’t at all critical anyway.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

Ethan_Hansen

  • Full Member
  • ***
  • Offline Offline
  • Posts: 114
    • Dry Creek Photo
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #6 on: February 11, 2012, 12:54:41 pm »

The argument for calibrating your display gamma to be the same as your working space is that it makes for one less time when output levels need to be modified and collapsed. As Andrew pointed out, sRGB emulates 20 year old CRT display technology. Any reduction in level compression from matching calibration and working space gamma to sRGB will be overwhelmed by the difference between the native gamma of your LCD and sRGB.

In the real world, however, you will likely never see any visible difference in gradient smoothness or output banding between 2.2 gamma and sRGB. i1Profiler's problems with sRGB calibration are another matter. That's a bug. Tried it on a screen here and see the same problem.

WayneLarmon

  • Full Member
  • ***
  • Offline Offline
  • Posts: 162
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #7 on: February 11, 2012, 03:05:48 pm »

Quote
There is no reason to select sRGB, especially if you hit what is a bug in the software.

As I said in my other post, I now use a NEC PA241W, calibrated with SpectraView II and an i1 Display Pro.  The PA supposedly can emulate sRGB exactly.  I thought that it would be better to get the TRC curve to match sRGB.   

I read somewhere that the difference between the sRGB curve and gamma 2.2 shows up in shadow tones.  I noted a big discrepancy in shadow tones with my previous monitor (HP LP2065 calibrated with MonacoOPTIX/DTP-94) and prints.  Which are usually from a mini-lab printer.  (Yes, I know that there is no such thing as an sRGB printer--I looked at 3D plots of a lot of printers on Dry Creek Photo's site.  Most mini-lab printers do fit in sRGB.)  I was sort of hoping that the PA monitor's shadow tones would better match prints.  (I only got the PA a few weeks ago and haven't edited any images that have been printed yet.)

I will be the first to admit that I only have a fuzzy understanding of color theory, even after reading your book.  And reading all the tutorials on Dry Creek Photo.

Wayne
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #8 on: February 11, 2012, 03:55:22 pm »

The PA supposedly can emulate sRGB exactly. 

Exactly? Probably not although if so, I’d sure like to see proof. Note, calibrating to even a luminance that doesn’t fall within the sRGB spec would invalidate exactly.

And if you have a PA, use SpectraView or MultiProfiler and forget i1P.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WayneLarmon

  • Full Member
  • ***
  • Offline Offline
  • Posts: 162
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #9 on: February 11, 2012, 07:22:25 pm »

Quote
Exactly? Probably not although if so, I’d sure like to see proof. Note, calibrating to even a luminance that doesn’t fall within the sRGB spec would invalidate exactly.

Well, the resulting sRGB emulation monitor profile matches up visually with sRGB when I compare them at http://www.iccview.de/content/view/3/7/lang,en/  (or with the Argyll 3D profile VRML generating programs that do much the same thing that the iccview site does.)  A lot closer than how other monitor profiles match sRGB. 

But no, it isn't an exact numerical match.  I think that would be expecting too much from a $250 i1DP.

Quote
And if you have a PA, use SpectraView or MultiProfiler and forget i1P.

I do use SpectraView on my PA241W.  SV is the only way to make the monitor be (almost) sRGB, at the monitor level.  SV makes the monitor match the target and then writes a linear 'vcgt' table in the profile.   I only use iProfilier to calibrate my non-NEC secondary monitors.  I did use SV to profile my non-NEC monitors and the profiles were close to the profiles that iProfilier made (when examined as 3D gamut plots.)  Which is a good cross check, isn't it?

Wayne
Logged

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #10 on: February 14, 2012, 12:43:57 am »

I have no idea why they have an sRGB setting (or why you’d use it) when 2.2 is available. Just use 2.2.

Why do you say that? If you calibrate it to sRGB TRC then programs such as IE that don't take into account anything will show images with the proper tone curve. If you calibrate to gamma 2.2 then you will see the shadows too dark and the contrast a little bit different than it should be in programs such as IE.

OTOH for viewing TV and movies and sometimes games, gamma 2.2 often looks a bit nicer.
Logged

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #11 on: February 14, 2012, 12:55:45 am »

Exactly? Probably not although if so, I’d sure like to see proof. Note, calibrating to even a luminance that doesn’t fall within the sRGB spec would invalidate exactly.

And if you have a PA, use SpectraView or MultiProfiler and forget i1P.

It sure gets closer than almost any standard gamut monitor, most of those fall short in one way or another or don't track saturation curves all that well, etc.

NEC PA241W calibrated sRGB mode:






how many regular old monitors get everything matching so well? Most will have at least one primary fall short, most have the saturation tracking for various colors going all up and down along the way, some have the primary luminance tracking off, etc.

here are measurements from a an sRGB monitor with unusually numerous controls (many have the luminance and saturation color curves a lot farther off):




and you might get luminance and saturation primary curves like say:


« Last Edit: February 14, 2012, 12:57:54 am by WombatHorror »
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #12 on: February 14, 2012, 10:00:31 am »

Why do you say that? If you calibrate it to sRGB TRC then programs such as IE that don't take into account anything will show images with the proper tone curve. If you calibrate to gamma 2.2 then you will see the shadows too dark and the contrast a little bit different than it should be in programs such as IE.

The differences in the TRC of sRGB and a true 2.2 gamma curve is insignificant. And in one case, you catch a bug in the process of setting that option. Plus any non ICC aware application is, well not color managed. You really think that your LCD can behave as a true (as exactly defined) sRGB device and even so, that would have any meaningful role in IE or other non ICC aware app’s? Your LCD is using P22 phosphors I suppose? Talk about debating how many ICC profiles can dance on the head of a pin.
« Last Edit: February 14, 2012, 10:06:22 am by digitaldog »
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #13 on: February 14, 2012, 12:50:37 pm »

The differences in the TRC of sRGB and a true 2.2 gamma curve is insignificant. And in one case, you catch a bug in the process of setting that option. Plus any non ICC aware application is, well not color managed. You really think that your LCD can behave as a true (as exactly defined) sRGB device and even so, that would have any meaningful role in IE or other non ICC aware app’s? Your LCD is using P22 phosphors I suppose? Talk about debating how many ICC profiles can dance on the head of a pin.

It's not totally insignificant. With plenty of photos it's readily noticeable (between using gamma 2.2 and sRGB TRC).

And OK sure you get a bug that crashes the calinbration program so obviously you simply can't set sRGB TRC with that program for now but that just means you need to send in a bug report not decide to never use sRGB TRC, come on.

Yes, the better wide gamut monitors in their sRGB mode very, very much can behave as sRGB devices when used with non-display managed programs such as IE. Did you not see my charts above? The first set? Taken with samples that had no ICC color management applied to them whatsoever? Those sRGB mode non-ICC managed measurements on my PA241W are much CLOSER to the exact spec for sRGB than any I have ever taken on any of my regular old non-pro level sRGB monitors ever produced even using ICC management on the sample patches using when using profiles made from well regarded programs such as CEDP.

You are wayyy off base saying that is dancing on the head of a pin. Utterly wrong. You seem to forget that the fancy wide gamut monitors with high bit 3D internal LUTs are fully capable of shifting the primary locations around and you can get them right on and you can also see that these sets are so linear that they track the saturation curves and primary luminance curves essentially perfectly as you move their locations around (many less fancy monitors have somewhat all over the place curves and even after fancy CEDP calibration they are still only partially corrected).

Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #14 on: February 14, 2012, 01:02:34 pm »

Yes, the better wide gamut monitors in their sRGB mode very, very much can behave as sRGB devices when used with non-display managed programs such as IE.

Again, the sRGB specifications are very well defined, down to the phosphors and ambient light conditions. Are you actually targeting the lumanice to 80 cd/m? P22 Phosphors? Because if you don’t, you are not producing sRGB as specified.

You might get “close” with some emulation but there is no reason to split hairs here especially when trying such a setting totally hoses the calibration anyway!

Quote
You are wayyy off base saying that is dancing on the head of a pin. Utterly wrong. You seem to forget that the fancy wide gamut monitors with high bit 3D internal LUTs are fully capable of shifting the primary locations around and you can get them right on and you can also see that these sets are so linear that they track the saturation curves and primary luminance curves essentially perfectly as you move their locations around (many less fancy monitors have somewhat all over the place curves and even after fancy CEDP calibration they are still only partially corrected).

Show me where you are getting the exact specifications for sRGB as defined by HP and MS (http://www.w3.org/Graphics/Color/sRGB)
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #15 on: February 15, 2012, 02:12:26 pm »

Again, the sRGB specifications are very well defined, down to the phosphors and ambient light conditions. Are you actually targeting the lumanice to 80 cd/m? P22 Phosphors? Because if you don’t, you are not producing sRGB as specified.

You might get “close” with some emulation but there is no reason to split hairs here especially when trying such a setting totally hoses the calibration anyway!

Show me where you are getting the exact specifications for sRGB as defined by HP and MS (http://www.w3.org/Graphics/Color/sRGB)

You may as well say why bother for even gamma 2.2 just use whatever it does naturally, it's all splitting hairs if you don't have the exact viewing conditions in the spec, etc.
Anyway, at night time I actually do tend to use it around 80 cd/m^2 and somewhat close to spec ambient lighting, but when it is daytime I don't since that would be foolish and you need to adjust the luminance up, etc.

And as I said look at the gamut plot, the primaries and secondaries are all dead on and not just that, but as I also said, the way the saturation levels and lum track for them is actually better without ICC apps running than on my older, regular old sRGB monitors running ICC apps with a high quality monitor profile.

Sure there can be metameric differences between P22 phosphors and various LCD filters+backlights but it's not like using an ICC aware program does anything about that and it's also true that the metameric differences vary from person to person. Nothing less than spectral distribution color management would really work to fix that but such systems are used by regular programs and the sRGB ICC profiles are not defined that way, etc. so that is all beside the point. As measured by probe, you can dial them primaries in as perfectly as you can anything else with the monitor that he has.

Whether I use it during the day or night I can see a difference between gamma 2.2 and sRGB TRC when browsing images using IE. For some monitors that are quite well behaved, the biggest noticeable difference when using a monitor set to gamma 2.2 and a monitor profile and ICC aware apps can actually be the sRGB TRC vs gamma 2.2 difference and for a NEC PA monitor it is the only visible difference at all. If he want to calibrate one of his sRGB modes (the one for non TV/movie) stuff to TRC why should he not? I mean he should. Ideally. Obviously it goes without saying that if the program crashes during sRGB TRC he shouldn't use sRGB TRC with that program, I mean he can't. All he wanted to know is if anyone else had the same bug so he knows what to report to X-Rite in terms of getting it fixed or whether or not anyone found a way around the bug.

« Last Edit: February 15, 2012, 02:16:28 pm by WombatHorror »
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #16 on: February 15, 2012, 02:38:33 pm »

You may as well say why bother for even gamma 2.2 just use whatever it does naturally, it's all splitting hairs if you don't have the exact viewing conditions in the spec, etc.

Yes, I would recommend a native TRC gamma to many users.

Quote
Anyway, at night time I actually do tend to use it around 80 cd/m^2 and somewhat close to spec ambient lighting, but when it is daytime I don't since that would be foolish and you need to adjust the luminance up, etc.

So nighttime use is different from daytime use? That opens a whole can of worms that are far more critical than the tiny differences between a 2.2 gamma and an sRGB 2.2 TRC isn’t it?

Quote
Sure there can be metameric differences between P22 phosphors and various LCD filters+backlights but it's not like using an ICC aware program does anything about that and it's also true that the metameric differences vary from person to person.


Can be differences? I think it is a bit more clear cut than that. Your take is, you need to nail sRGB and to do so, it is critical to have a 2.2 TRC instead of a simple gamma curve. I don’t buy that. Now when asked if you can hit something far more critical, the sRGB spec for cd/m2 and chromaticity, that isn’t all that important to the debate.

The bottom line is, there is yet any justification for either the 2.2 sRGB TRC setting nor the bug it introduces in the software.

Quote
As measured by probe, you can dial them primaries in as perfectly as you can anything else with the monitor that he has.

So your take is, no matter what values I dial in, every instrument is going to provide that exact value? It might report what you asked for, I’d be hard pressed to believe you’ll always get it.

Quote
Whether I use it during the day or night I can see a difference between gamma 2.2 and sRGB TRC when browsing images using IE.


I have no reason to doubt that. What you haven’t proven is that one is closer to sRGB than the other or that being close to sRGB is even useful. There is a difference, great. There should be. There should be a difference calibrating to 80 cd/m2 (if you can really hit that) and 90cd/m2. I’d expect you would see a difference. Is that useful? Is that really producing sRGB (or is producing sRGB as defined even something to attempt?).

Quote
If he want to calibrate one of his sRGB modes (the one for non TV/movie) stuff to TRC why should he not?

Because it breaks the software for one. And it might be just a feel good option or something placed into the product solely for a marketing competitive matrix diagram.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #17 on: February 15, 2012, 05:27:27 pm »

Yes, I would recommend a native TRC gamma to many users.

Not sure what you are saying here.
I'm not sure many calibration/profiling programs even allow that do they?
Many monitors have TRCs going all over the place along the way are something way different than anything close to gamma 2.2.
And if it is some messy random TRC how will the profile even characterize it?


Quote
So nighttime use is different from daytime use? That opens a whole can of worms that are far more critical than the tiny differences between a 2.2 gamma and an sRGB 2.2 TRC isn’t it?

Whatever the differences you can see the difference between sRGB TRC and gamma 2.2 in either case so why avoid it?


Quote
Can be differences? I think it is a bit more clear cut than that. Your take is, you need to nail sRGB and to do so, it is critical to have a 2.2 TRC instead of a simple gamma curve. I don’t buy that. Now when asked if you can hit something far more critical, the sRGB spec for cd/m2 and chromaticity, that isn’t all that important to the debate.

2.2 is the simple gamma curve, sRGB TRC is the TRC that is not a pure simple gamma curve.

The sRGB spec for cd/m^2 is not even something you'd want in all viewing environments. If it is a bright day and the windows are open, come on. When it's dark and controlled they I do tend to set it around 80 cd/m^2.

It depends upon the monitor, but for some when you toggle between profile on and off, the biggest visual difference actually could be gamma 2.2 TRC vs. sRGB TRC and not the other aspects (well other than perhaps the white point, of course). I mean I've tried it and seen. It depends on the monitor though. Many profilers, most even, struggle somewhat to fix up saturation tracking all that well for the monitors where that is not so hot.

And for one of the better wide gamut monitors, they can get all specs so dead on that the TRC is the only thing left. If I put it in sRGB emulation mode with monitor calibrated to gamma 2.2 and compare images between IE and Firefox the only differences, whatsoever, that you see is between IE not correcting the sRGB image's display for the monitor being gamma 2.2 instead of sRGB TRC.


Quote

The bottom line is, there is yet any justification for either the 2.2 sRGB TRC setting nor the bug it introduces in the software.

Funny that the ICC and so many others have even bothered storing TRC information then.


Quote
So your take is, no matter what values I dial in, every instrument is going to provide that exact value? It might report what you asked for, I’d be hard pressed to believe you’ll always get it.
 

Of course not, but with that attitude why even bother calibrating at all? And when it comes to TRCs, if you plot the measurements of a monitor in gamma 2.2 and one in sRGB TRC with a bunch of probes, most probes actually do show a straight line across with 2.2 and a curved one for sRGB TRC. Even if the plots don't quite overlap the general shape, from what I've seen, is generally pretty close. They tend to get that better than the absolute values of brightness, which don't matter as much, in agreement.

Quote
And it might be just a feel good option or something placed into the product solely for a marketing competitive matrix diagram.

Toggle between viewing an sRGB image as gamma 2.2 or as sRGB TRC and tell me it's just marketing BS. With many images the difference is plenty easy to see.
It's not as huge as swapping D50 and D93 or something and on some monitors the rest of calibration sometimes matters even more (but definitely not always) but it's still readily visible so why is the rest important and this part just marketing BS?
Logged

digitaldog

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 20652
  • Andrew Rodney
    • http://www.digitaldog.net/
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #18 on: February 15, 2012, 05:57:14 pm »

Not sure what you are saying here.
I'm not sure many calibration/profiling programs even allow that do they?

Yes, quite a number do, including SpectraView and at least the last number of generations of X-Rite products.

Quote
Many monitors have TRCs going all over the place along the way are something way different than anything close to gamma 2.2.

Which is why we have the Native Gamma option. Why alter the behavior as you propose to sRGB when you can leave it alone and just characterize it with the profile.

Quote
And if it is some messy random TRC how will the profile even characterize it?

Of course it will.

Quote
Whatever the differences you can see the difference between sRGB TRC and gamma 2.2 in either case so why avoid it?

Yes, as I said, you can see the difference in all kinds of calibration targets. So what? Calibration should be set to provide a visual match to a print in most cases (that is what most users desire). The gamma isn’t going to play a role here in ICC aware applications. For years, prior to OS X, Mac users calibrated to a Gamma 1.8 because outside ICC aware applications, the OS made that silly assumption. But inside ICC aware applications, it made no difference. Smart users calibrated their displays to 2.2 because that if far closer to the native gamma of the display and, there was no visual difference in ICC aware applications plus closer to native meant less banding (the reason Native has been an option for years in better software products). IF you cared about how non ICC aware app’s previewed their inaccurate color (cause they are not ICC aware), you used 1.8 otherwise everything appeared a tad dark (yes, there was a visual difference, so what?). But IN ICC aware applications, 1.8 or 2.2 produced the same previews, the former however introducing more banding in many display systems.

Quote
2.2 is the simple gamma curve, sRGB TRC is the TRC that is not a pure simple gamma curve.

You are preaching to the choir! If you carefully re-read what I wrote, you’ll see I’ve gone out of my way to separate language discussing a simple gamma curve with a TRC curve when discussing the two.
 
Quote
The sRGB spec for cd/m^2 is not even something you'd want in all viewing environments.


I question in this post, if you’d even really want it (or can actually really hit it). You seem to feel otherwise for reasons I as yet don’t understand.

Quote
If it is a bright day and the windows are open, come on. When it's dark and controlled they I do tend to set it around 80 cd/m^2.

As I said, if you have such conditions, you have bigger problems than what gamma to calibrate to! You should control you editing conditions so they are always consistent and controllable.

Quote
It depends upon the monitor, but for some when you toggle between profile on and off, the biggest visual difference actually could be gamma 2.2 TRC vs. sRGB TRC and not the other aspects (well other than perhaps the white point, of course). I mean I've tried it and seen.

First off, seeing a before and after difference tells us nothing about the quality of the ‘after’ calibration. Whether it meets sRGB specifications or matches a print. I don’t know why you keep going back to seeing a difference in two settings. That is totally to be expected. Other than there are differences, the results thus far say nothing further.

Look, if you want to calibrate to a setting called sRGB and you get the match you want, great. But to propose that using that setting in some why makes your LCD display produce sRGB specified is not something I’m buying.
Logged
http://www.digitaldog.net/
Author "Color Management for Photographers".

WombatHorror

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 299
Re: i1Profiler 1.2.0 sRGB bug?
« Reply #19 on: February 15, 2012, 08:16:57 pm »

Yes, quite a number do, including SpectraView and at least the last number of generations of X-Rite products.

Oops you are correct.

Quote
Which is why we have the Native Gamma option. Why alter the behavior as you propose to sRGB when you can leave it alone and just characterize it with the profile.

Why not leave it at native gamma? Maybe because it's nice to have the 95% of programs that are not color aware look nice? It is sure nicer using the monitor to watch TV/movies/play games/edit in premiere pro/watch videos/for the times you use IE instead of Firefox/desktop/3D programs/games/etc. So why shouldn't someone calibrate to sRGB TRC for some of that stuff and to gamma 2.2 for the rest? Why leave it to just a few color aware programs and have to trust the CMM in all of them?

And in this case here, he has a wide gamut monitor and most likely the only reason he is even in the sRGB emulation mode is to deal with non-managed software. For the most part, when you are using an sRGB emulation mode on a wide gamut monitor it is because you are dealing with non-color aware programs, otherwise you probably are going to want to have it in native gamut mode.

Quote
Of course it will.

Hmm yeah I guess maybe it can also be stored as a table form too which would work.
I will have to look into it more for native gamut photo editing modes. I'm not sure it makes any difference on my PA though since I don't see any banding due to the high bit internal LUT anyway. Perhaps it might improve contrast ratio or something.

Quote
Yes, as I said, you can see the difference in all kinds of calibration targets. So what? Calibration should be set to provide a visual match to a print in most cases (that is what most users desire).
The gamma isn’t going to play a role here in ICC aware applications.

Yes, but what about for all the non-ICC aware stuff?
(and in the OP's case, if he is in the sRGB emulation mode, he very well may be in that mode specifically because he plans to use non-ICC aware programs)

Quote
For years, prior to OS X, Mac users calibrated to a Gamma 1.8 because outside ICC aware applications, the OS made that silly assumption. But inside ICC aware applications, it made no difference. Smart users calibrated their displays to 2.2 because that if far closer to the native gamma of the display and, there was no visual difference in ICC aware applications plus closer to native meant less banding (the reason Native has been an option for years in better software products). IF you cared about how non ICC aware app’s previewed their inaccurate color (cause they are not ICC aware), you used 1.8 otherwise everything appeared a tad dark (yes, there was a visual difference, so what?). But IN ICC aware applications, 1.8 or 2.2 produced the same previews, the former however introducing more banding in many display systems.

Again, what about when someone flips on a tv show or a movie or to a game or does some browsing and looking at other people's images and happens to be using one of the many non-fully aware browsers?

And I don't think it is a so what if IE shows things with the wrong TRC. You can start telling people to lift their shadows a little and end up giving bogus advice.

As for banding and such it depends whether it's an internal high bit LUT monitor like the OP has or someone relying on an 8bit graphics card LUT. And if you are dealing with non-iCC aware it's all moot since you need it to be calibrated and not merely profiled.

Quote
You are preaching to the choir! If you carefully re-read what I wrote, you’ll see I’ve gone out of my way to separate language discussing a simple gamma curve with a TRC curve when discussing the two.
  

That's what I thought but then you said something about how I insisted things need to be set to the 2.2 sRGB gamma instead so....

Quote
I question in this post, if you’d even really want it (or can actually really hit it). You seem to feel otherwise for reasons I as yet don’t understand.

I thought you were the one who was insisting it had to be hit since, if not them why even bother with what the TRC is, etc. etc., maybe we misunderstood each other.

And you can hit it with some monitors. I have it in sRGB emulation mode at sRGB TRC and 85cd/m^2 right at this moment and it is just about near min black level, the contrast ratio is a trace, TRACE lower than at 120 cd/m^2 but so what? the black level is much deeper and my eyes are not getting burned out and the calibration actually tested out to be a bit more uniform than the one made at 120 cd/m^2 so, no, it has not gone all whacked out.  I'm in a dim room right now, why do I want a high black level, faded looking image and my eyes burned out?


Quote
First off, seeing a before and after difference tells us nothing about the quality of the ‘after’ calibration. Whether it meets sRGB specifications or matches a print. I don’t know why you keep going back to seeing a difference in two settings. That is totally to be expected. Other than there are differences, the results thus far say nothing further.

I keep going on about how you can see the difference between an sRGB image displayed with sRGB TRC vs. gamma 2.2 TRC because you said the difference was nothing and like dancing on the head of a pin and that he shouldn't even bother setting his sRGB emulation mode to sRGB TRC for general work. I was just saying that, to me at least, it is a lot more noticeable than that. Now all of a sudden you seem to say that the difference is noticeable.

Quote

 But to propose that using that setting in some why makes your LCD display produce sRGB specified is not something I’m buying.

I'm saying that if you are switching from photo editing mode to sRGB emulation mode to do say perhaps some browsing on the web using IE that setting it to sRGB TRC does get you proper sRGB image display while setting it to gamma 2.2 makes it a little bit off and that with many, if not all images, the difference definitely can be seen easily enough even if it is not radically extreme or anything.
Logged
Pages: [1] 2   Go Up