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richardj21724418
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richardj21724418
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Jan 09, 2019
01:36 AM
antonior23254972 wrote . I have: mac pro, spider 4 and Benq sw240 Calibration fails with an error “conflict” with other software. (Spyder software was deleted from the Mac) Any clue on what may be wrong? Sorry, I'm rather out of my depth when it comes to the Mac Pro and the Spider 4. However, it sounds like Palette Master Element has detected that the Spyder software is running and this may might upset the calibration procedure. Do you use the Spyder software for calibrating other monitors? If not, perhaps you could uninstall the Spyder software, or at least disable it? As I said, my knowledge is limited and I wouldn't want to suggest doing something which might mess your system!
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Dec 27, 2018
12:19 AM
It sounds like you may not be using the correct profile for the monitor display mode. e.g. if you're using the monitor in AdobeRGB mode you must use the AdobeRGB profile, otherwise images will look too saturated. You must also be running colour managed applications (i.e. applications that take account of the monitor profile and don't assume sRGB).
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Dec 20, 2018
12:52 PM
oro.photos wrote I'm using the Spyder5Pro. I've tried many times to calibrate it but the end result has either been way to warm/saturated/contrasted or on the complete opposite side of the spectrum- desaturated/no contrast and with a strange greenish color shift. I tried assigning the RGB primaries as sRGB but no luck. I'm close to giving up and just selling the monitor for something cheaper since it seems proper calibration is above my head What about if you simply set the factory sRGB display mode? Do the colours seem about right then? Sorry if this is obvious but bear in mind when you use the monitor in sRGB mode you will need to set the sRGB IEC61966-2.1 display profile for colour management in your PC. Not that this will affect applications that are not colour managed (e.g. your videos?). For applications that are colour managed the shadows will appear a bit dark, for the reason I mentioned earlier (the monitor is calibrated to a gamma of 2.2, not the correct sRGB tone curve). It may well be you're doing nothing wrong and it could be a problem with the Palette Master Element Software and/or the Spyder5Pro. I feel your frustration!
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Dec 20, 2018
09:09 AM
2 Upvotes
aiur4 wrote Their calibration software is just BS. Seriously? Do you see that green light? I did notice a problem like that when I was first trying things out with an old version of the software. I think it could happen when I quit the software mid calibration. Then I had to completely disconnect the monitor from the power for a few minutes (not just turn it off) in order to reset the USB link. I never have a problem now. PME always starts up looking like this:- It's possibly important to have a good USB connection to the monitor with a good USB cable, not too long and connected directly to the PC, not via a hub. BenQ advise you don't have anything plugged into the USB ports on the monitor when calibrating but I've not found this to be a problem. Indeed, I usually plug the i1Display Pro into the monitor. Or I may have a keyboard and mouse attached. The software isn't great but it's gradually improving. What version of PME are you running (click the info button in the bottom right)? I'm using V1.2.9 and am about to install a newer version.
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Dec 20, 2018
08:52 AM
oro.photos wrote When I run a sRGB calibration, the end result is has more saturation and contrast than my Macbook Pro display or iPhones. It very much sounds like the monitor is somehow calibrated/set to a mode with a wider gamut than sRGB, such as AdobeRGB or the native gamut. Applications that aren't colour managed will look too saturated in wide gamut modes. Try setting the Color Mode to sRGB. This will be the factory sRGB calibration. My guess is this will look right. If it doesn't there's little point in attempting a calibration to sRGB! When you say you run an sRGB calibration, are you performing a hardware calibration with the Palette Master Element Software using a device like the i1 Display Pro? If so, you will need to select Advanced mode and select 'sRGB' in the RGB Primaries box on the Display Settings page. The page should look something like this:-
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Nov 14, 2018
09:44 AM
https://forums.adobe.com/people/Rommen+%7C+Bravenboer wrote Same problem here! When I calibrate with Pallet Master Pro colors are very desaturated. I'f contacted Benq the Netherlands they asked calibration report and the answer was that the numbers are in spec. I bought the monitor for its hardware calibration / profiling capabilities but its not usable. When you calibrated with PME, what RGB Primaries did you select in the options box? The ICC profile created is only valid for Native primaries, although confusingly they generate it for all calibrations. This means if you attempt to use it for calibrations to RGB Primaries other than native, the colours will appear desaturated. Use the correct standard profile for the RGB Primaries you calibrated to. e.g. if you calibrated to AdobeRGB primaries, use the Adobe RGB (1998) profile. I hope this fixes it. It did for me and it has made a huge difference to my liking of the monitor.
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Nov 14, 2018
09:34 AM
I'll also add, make sure you have something selected in the RGB Primaries option box. I been using some settings files created by an earler version of PME, before they supported the RGB Primaries option. The files may not be completely compatible with the current version V1.29. As I result, the setting in the RGB Primaries box loads as blank. I may be wrong but think on a previous version this meant defaulting to performing a native calibration (the profile file name suggests that). However, with version V1.2.9 the calibration is closer to AdobeRGB, which might be why someone reported it looks desaturated.
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Nov 14, 2018
08:18 AM
1 Upvote
irfani7193203 wrote I also seem to have these problems, from my extensive testing I deduced the following problems with Benq SW2700PT I've opened another thread on this. Sorry, probably a mistake. It's here:- BenQ SW2700PT and colour management of hardware calibrated monitors I agree with all your points. However, I think you may be making the same assumption as I did last year. Once it clicks you do feel stupid! I think BenQ could do more to help explain, but I guess it's obvious to them. With 'conventional' PC side calibration and profiling the software performs a characterisation and then outputs an ICC profile file for you to use as the display profile. With this monitor, that's how it works in native space. However, when you calibrate to anything other than the native space, you use the standard ICC profile file for that space. You don't use their profile file (so why confuse us by generating it?) i.e. if you calibrate to AdobeRGB primaries, you use the standard AdobeRGB profile. That's because the monitor uses 3D LUTS to emulate the actual colour space. If you do that I think you'll find it works well, remarkably well in fact. The only minor problem is sRGB mode. The software doesn't support the correct sRGB tone curve (modified 2.2 gamma). Amongst other things it means the shadows appear too dark. They've even got it wrong in the factory sRGB calibration. I'll ask BenQ if they can add this option. It's a shame because of all the emulation modes that's the most useful IMO, because it's the default on unmanaged applications and you can't fix unmanaged applications with an ICC profile, the monitor has to be sRGB. I agree about the puck. It would be so nice if changing display mode could be linked somehow to changing the monitor profile. It might actually be easier to do the other way around and have a little desktop application that simultaneously switched the monitor mode and the profile. I wonder if the developer of the excellent DisplayProfile could add monitor support as a chargeable 'Pro' option. I'd pay.
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Nov 14, 2018
07:57 AM
1 Upvote
An update to my first point. The profile produced does in fact appear to be the native gamut, as I thought last year. I don't know why I thought otherwise. It may have to do with installing the new version of PME and loading settings from settings files created with the old version, before the RGB Primaries option was added. So the only remaining issue for me is adding an option to calibrate to the sRGB TRCs. I'll put in a request for this.
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Nov 14, 2018
06:04 AM
thedigitaldog wrote What you apparently didn't understand, maybe still do not, is that even if a display like a PressView produces ColorMatch RGB perfectly, a display profile is still absolutely necessary and always used in ICC aware applications; always! They cannot not have such a profile in the chain. I don't know why I can't express this. I've never said an ICC display profile isn't necessary for a color managed environment. Just if you have a display that emulates a standard colour space, you use the ICC profile for that space. You shouldn't need to characterise the display and produce another profile. If you attempt it, the result will simply be a profile for the standard space. Why bother? If you find the need to characterise the display and produce another profile, then the display isn't emulating the standard colour space properly.
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Nov 14, 2018
03:25 AM
Thanks Neil for taking the time to reply and for your excellent reasoned comments. I appreciate it. It seems you're agreeing with the principle that if a display which has been perfectly programmed to meet a standard colour space then it can be used the ICC profile for that colour space and obtain correct results. It's something I seem to have struggled to get some people to accept, but perhaps that's a failure on my part to express it well. It's just you're sceptical that dedicated hardware in consumer level products can perform to the accuracy required. Once calibrated, my BenQ actually seems to do rather a good job of emulating AdobeRGB space. I've confirmed the accuracy by subsequently profiling using the i1Profiler, but I'm sure a professional like yourself would look at it more critically than me. I tried programming to L* too and that also appeared to work, but it was only a brief inspection and I didn't confirm the accuracy. So it appears the monitor should be perfectly capable of doing a decent job of emulating sRGB - the problem is just the software doesn't provide the option to program it with the correct sRGB TRC curves. I think as hardware 3D LUT technology has become cheaper it's become feasible to incorporate it into consumer level displays. It's no longer 'rocket science'. I'm not saying the BenQ implements it this way but supposing you had a big (4GB?) LUT to translate 30-bit input space to 30-bit native space. How much better do you need than that? Is the software 3D translation technology in PC side profile conversion really superior? I can't see why you'd go to the trouble of designing a monitor that can be programmed to emulate a standard colour space, then expect to have to characterise it and use it with a non standard profile. Effectively we're talking about differences in the profile connection space between the computer and the monitor. This can be some arbitrary space, determined by the native characteristic of the monitor. Or it can be a standard space, provided the monitor has been setup to respond correctly. Much as your CMYK analogy. Regarding sRGB. I'm certainly not intending to promote it as a working space but I guess some could argue there are merits in using sRGB for display, and not just because of compatibility with non colour managed applications. That's because of the bit depth bottleneck of the link. I imagine most of us have 10-bit component connections between computer and display, some may be 8-bit. This limits the number of values you can communicate to the device, so you don't want to waste valuable tonal resource on describing a larger gamut than you need. For instance, in 8-bit mode in Photoshop I doubt you'd want to use a wide gamut working space like AdobeRGB or ProPhoto RGB, if you know your colours are all going to be contained in sRGB gamut. Why opt for a larger tonal granularity than necessary for the job? No, it isn't a colour space I'd normally display in. I just came across this sRGB mode 'misconfiguration' when I was investigating something else and thought I'd mention it and ask if it seemed acceptable in a hardware calibrated monitor. It was never my intention for it to evolve into some deep philosophical discussion! I'd mistakenly assumed the concept of a hardware calibrated monitor was already a given.
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Nov 13, 2018
02:48 PM
Last year I posted about problems I was having with profiles generated by Palette Master Element (PME) on the BenQ SW2700PT. I thought I'd post an update on my findings as it might help other owners of the SW2700PT and hardware calibrated monitors in general. My monitor is a couple of years old and was updated with firmware version V004 20161006, in case that's a factor. For calibrating I'm using the i1 Display Pro. It's necessary to understand that colour management of a hardware calibrated monitor is not handled in quite the same way as a 'conventional' monitor. I think this could be one reason why people report having profile problems. It's probably obvious to some but it's clear from the discussions I had on the Color Management Forum that it can be a bit of an intellectual challenge if you're set in your thinking of how colour management 'should' work. I'll admit, I didn't get it at first. I think BenQ could do more to educate users, rather than assume we all understand. There are also several calibration & profiling issues with this monitor and the Palette Master Element (PME) software. What I've found is:- 1) The profile produced by PME is always produced to the same colour space, regardless of the colour space you're calibrating to. I'd assumed the profile was made to native space but in fact it's closer to AdobeRGB. As it doesn't relate exactly to any of the calibration colour spaces it means it's useless. It also means it's not possible to obtain a valid profile for the native mode using PME. If you want to use the native mode, you'll have to create a profile with some other software. 2) When calibrating to the RGB Primaries you are calibrating the monitor to standard colour spaces by programming the internal 3D LUTs. This means the profile you use for colour management is the profile for those standard spaces. e.g. when you've calibrated to Adobe RGB, the ICC profile you use is the standard Adobe RGB profile. If the monitor is properly calibrated to Adobe RGB, there should be no need to attempt to create a monitor specific profile. 3) The caveat is the gamma should be set to the correct value for the standard space. If you use a different gamma, I think you'll need to create a monitor specific profile with other software. 4) I've only checked Adobe RGB, sRGB and L*. With Adobe RGB it works well. I've verified it with i1Profiler and the profile created is very similar to Adobe RGB - the discrepancies are within the range of temperature drift. I think it works correctly with L* too (using the Lstar profile). Unfortunately, there's a problem with sRGB mode. PME doesn't support the correct sRGB tone reproduction curve (linear for about the first 4%, then a gamma of about 2.4). The closest you can set is a single gamma curve of 2.2, which is what's required for Adobe RGB. This means if you apply the standard sRGB profile the shadows will appear too dark and the mid range contrast will look wrong. Of course, you can create a profile for this mode (or just change the TRC values in the sRGB profile to a gamma of 2.2 to match the calibration). However, one of the main reasons for using sRGB is for viewing non colour managed applications. These blast data straight at the monitor and for that, the monitor should be calibrated with the correct sRGB TRC. 5) Even the factory sRGB mode hasn't been calibrated correctly. It uses a single gamma of 2.2, the same as used for the factory Adobe RGB mode. Provided you can live with these issues I think it's actually a pretty decent monitor for the money. I know some people won't be happy with the uniformity but at my level it hasn't really bothered me.
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Nov 13, 2018
09:59 AM
I came across this article. I hope some of you will find it interesting and educational. (I didn't write it!) https://photographylife.com/the-basics-of-monitor-calibration
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Nov 12, 2018
03:14 PM
Perhaps you guys need helping out. From NEC:- "The integrated 3D LUT with color emulation preset within the SpectraView series of products, can be used to transform the color space of the monitor to emulate that of the printer, or other color workflow device. The 3D LUT is a three dimensional table that maps colors into a different color space." From Google:- "3D lookup tables (3D LUTs) are used to map one color space to another"
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Nov 12, 2018
03:09 PM
thedigitaldog wrote richardj21724418 wrote thedigitaldog wrote Again, for at least the fourth time the answer is NO! Really? What do the 3D LUTS do then? They load a Look Up Table! Which has absolutely nothing to do with color space conversions for (at least) the 5th time. And the Look Up Table does what? What does it DO?
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Nov 12, 2018
03:08 PM
https://forums.adobe.com/people/D+Fosse wrote In addition, wide gamut monitors can usually be set to emulate the sRGB gamut. This is not a "color space conversion". It is just a way to limit the gamut to that of a standard gamut monitor, in case you need to work with non-color managed software. It's a way to turn your wide gamut unit into a standard one. A standard gamut monitor is even more different from sRGB, because not only the TRC, but the primaries are a little different too. So changing the monitor's input response from, say, native AdobeRGB to sRGB isn't classed as a colour space conversion? Really? That's an interesting concept. Does that mean if I change an image in Photoshop from AbobeRGB to sRGB working space I'm not performing a colour space conversion, merely limiting the gamut? What do you suppose the 3D LUTs in the monitor do?
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Nov 12, 2018
02:57 PM
thedigitaldog wrote Again, for at least the fourth time the answer is NO! Really? What do the 3D LUTS do then?
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Nov 12, 2018
02:02 PM
thedigitaldog wrote richardj21724418 wrote Sorry, but when the monitor is calibrated to a profile, like sRGB, surely this programs the colour space conversion to be performed inside the monitor? No, there is no such 'conversion'. Calibration is just that, a profile defines that behavior and then, again, for previews, Display Using Monitor Compensation is applied. Sorry, I know I should be ending this discussion but I have to ask. What do the 3D lookup tables in hardware calibrated monitors do? Nothing to do with colour space conversion by any chance?
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Nov 12, 2018
01:41 PM
https://forums.adobe.com/people/D+Fosse wrote richardj21724418 wrote When properly designed I believe internal monitor calibration tables provide superior colour space conversion than currently achieved by software profiles and limited GPU LUTs. I'm beginning to suspect you seriously misunderstand how this works. There is no color space conversion performed by the calibration, whether in the monitor LUT or the video card. That is not its role. Yes, hardware calibration is better than software calibration in the video card, but for other reasons. Functionally they do the same thing. Sorry, but when the monitor is calibrated to a profile, like sRGB, surely this programs the colour space conversion to be performed inside the monitor? If its input response is changed from native, that means the colour space has been changed? The monitor has to convert the standard sRGB input values it receives to its native space. If it does this properly, the correct ICC profile to use in this state is the standard sRGB profile. There should be no need for a second level of soft calibration within the PC and the use of a non standard ICC profile to describe the monitor characteristic. If there is, it rather negates the reason for hardware calibration of the monitor to sRGB space. Even a 'conventional' wide gamut monitor often has some sort of sRGB emulation mode, albeit uncalibrated. That must also involve colour space conversion. I don't know if we have some cultural differences but I seem to struggle to express myself in a manner which others here can comprehend. I guess that's probably mutual! With that in mind it's probably best if we wind down the discussion for now as I'm sure it's become a waste of energy for all of us. Perhaps in due course someone will come along and understand what I've been trying to get at. Until then, thanks to everyone for your replies. I appreciate the effort you've taken to try and educate me and the frustration you must have suffered!
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Nov 12, 2018
11:58 AM
thedigitaldog wrote No, the profile is not useless. No, your display isn't properly calibrated to a standard color space. You were told how and why. I'm sorry. I guess you must find me incredibly stupid and tedious, but please bear with me on this a bit longer. If I use the monitor in its native mode then, of course, I understand the need of a custom ICC profile to describe the monitor input response and to set the TRCs in the GPU. However, if I switch to the sRGB emulation mode the input response obviously changes completely. (e.g. in native mode an 8-bit RGB input value of 216/64/34 produces the same colour as 255/0/0 in sRGB mode - i.e. fully saturated sRGB red). How can an ICC profile describing native mode be of use in sRGB hardware emulation mode? I know the display isn't properly calibrated to standard sRGB colour space (that's where we came in!).Even leaving aside your issue with the P22 phosphors etc I know the monitor calibrates with a single 2.2 gamma curve. If it calibrated with the proper sRGB TRC I think I'd be perfectly satisfied with using it with the standard sRGB profile. I doubt 'soft' calibration of the PC to the monitor would improve on it. Does soft calibration (putting the responsibility on the PC side rather than the monitor side) really give better results? Why should it? (Apart from when monitor manufacturers get it wrong of course!).
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Nov 12, 2018
10:00 AM
thedigitaldog wrote richardj21724418 wrote I'm sorry to bore you further with this but hopefully I'm nearing the bottom of the 'rabbit hole'. I 'calibrated' the monitor to sRGB using PME. Remember, there's no meaningful ICC profile output file produced by PME when calibrating to a standard colour space. Sure there is. The calibration may be conducted in the panel like my SpectraView but an ICC profile still exists. It has to exist as all ICC aware applications still need that to conduct Display Using Monitor Compensation! The profile is meaningful. It's not loading a LUT itself to adjust the behavior to the display but none the less, it exists, it is used. After calibrating to sRGB PME does output an ICC profile, but it's useless. Regardless of the calibration colour space selected, the profile is always written for the native gamut. This means colours look way undersaturated, as you'd expect for a profile that's been designed for a wide gamut. Last year I had lengthy exchanges with BenQ about this (lengthy exhanges? Me?). I could not get any sensible response and it didn't help that it was in garbled English. The order PME does things doesn't feel entirely right. I tried to tell them that the profile was being created at the wrong stage, but they were having none of it! Then it dawned on me that if the monitor is properly calibrated to a standard colour space, you simply use the standard ICC profile for that colour space. Why not?
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Nov 12, 2018
09:40 AM
thedigitaldog wrote richardj21724418 wrote To verify this I calibrated the computer to the (calibrated) display using i1Profiler. This uses the same hardware and is based on similar software to PME, so you'd expect similar results... No, it absolutely isn't. Well, I know it uses the same hardware so I assume you mean the PME software isn't similar. Then I stand corrected. I thought I'd read somewhere that PME used a SDK from x-rite, but I may be wrong or it's completely different x-rite software. Then I'm impressed the results are so similar. I know they should be, but....!
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Nov 12, 2018
09:11 AM
https://forums.adobe.com/people/D+Fosse wrote richardj21724418 wrote What I'm saying is, if a monitor is calibrated to sRGB, then it should conform to the sRGB profile and comply with the sRGB response curve. Well, maybe, but again, there's no need. You'd make very complicated tables in the monitor LUT for no benefit whatsoever. All you achieve is to make life so difficult for the monitor that it starts producing artifacts. The profiles will handle this, whatever the discrepancies. There is no reason the calibration tables should do it, when the profile achieves the same goal with much less effort. What you're asking is to make the monitor a perfect sRGB device. That's hard work. No monitor ever was that, nor does it have to be. Color management picks up where the calibration leaves off. When properly designed I believe internal monitor calibration tables provide superior colour space conversion than currently achieved by software profiles and limited GPU LUTs. Why else do you suppose monitors are produced with hardware calibration? Just marketing? Would Eizo 'waste money' on it if it wasn't superior to PC calibration?
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Nov 12, 2018
08:59 AM
I'm sorry to bore you further with this but hopefully I'm nearing the bottom of the 'rabbit hole'. I 'calibrated' the monitor to sRGB using PME. Remember, there's no meaningful ICC profile output file produced by PME when calibrating to a standard colour space. I assume you're supposed to use the standard profile file. e.g. sRGB IEC61966-2.1. You guys will tell me that's wrong, although I still don't understand why. If the monitor is properly calibrated to sRGB, then sRGB is the right profile to use. However, I'm sure the monitor applies a single 2.2 gamma curve, not the correct sRGB TRC. This means the standard sRGB profile won't be correct for the calibration, which rather defeats one of the main purposes of having a calibrated sRGB monitor, namely to be able to view non-colour managed applications correctly. My work around was to produce a version of the sRGB IEC61966-2.1 profile, but modify it with a simple 2.2 gamma curve. This seems to work well, although it doesn't help with non colour managed applications which blast image data straight at the display. A real pity that. To verify this I calibrated the computer to the (calibrated) display using i1Profiler. This uses the same hardware and is based on similar software to PME, so you'd expect similar results....except the tone curves should get corrected. Bingo! To my eye I can't tell the difference between this calibration and the hardware calibration using my modified sRGB IEC61966-2.1 with linear LUTs in the GPU. I should probably reserve judgement until I've done some difference blend mode jiggery with Photoshop to closer inspect the differences, but on initial visual inspection I'm blown away by the match. For me it's further confirmation of the sRGB tone curve issue with the BenQ. It's a shame BenQ haven't got this quite right. The hardware calibration is very impressive and were it not for this TRC issue I think they'd have nailed it. Really, it's how hardware calibration should work IMO. If a monitor is properly calibrated to a standard space, you use the profile applicable for that standard space. You should need to mess with creating a non-standard profile. Why would you? The monitor is calibrated to the standard profile. I may try telling BenQ about this, but somehow I know, just know, it will be even harder than explaining to you lot!
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Nov 12, 2018
04:34 AM
I don't mean this to come across as offensive but I think you're living in the, "this is how it's done because we've always done it this way" world. I'm living in the idealistic, "this is how it should work" world. I think hardware calibrated monitors are still in their infancy, at least in the consumer market, and the marketing talent appears to have exceeded the engineering abilities! In theory I see no reason why a wide gamut monitor can't be internally calibrated to respond as near as possible perfectly to sRGB. In which case, for colour management, the monitor profile you use is the standard sRGB profile and the TRC LUTs in the PC are linear. That's what a calibrated monitor should do IMO. There should be no need for additional calibration on the PC side and non standard profiles when calibrated to standard colour spaces. However, it appears that internally calibrated monitors are not what they're cracked up to be, at least at the consumer level. I guess they have some advantage if you use them in their native gamut and use the internal TRC LUTs for calibration to your preferred white point.
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Nov 12, 2018
03:44 AM
https://forums.adobe.com/people/D+Fosse wrote What I'm saying is that this is not the reason for whatever problems you're seeing. This will not cause any visual tonal shifts on screen, as long as you have color management and profiles to correct for it. You're wasting energy here, you need to use it elsewhere. What I'm saying is, if a monitor is calibrated to sRGB, then it should conform to the sRGB profile and comply with the sRGB response curve. The monitor profile you use for colour management should then be the standard sRGB profile and there should be no need for anything other than linear TRC LUTs in the GPU. If it requires a non standard monitor profile and different TRC LUTs, the monitor hasn't been calibrated to sRGB. PME doesn't even produce a valid ICC profile file for the monitor if it's been calibrated to sRGB. So what are you supposed to use, other than standard sRGB? Of course, it would be possible to hardware 'calibrate' the monitor to sRGB then calibrate the PC to the monitor in the usual way, but then what's the point of hardware calibration? Obviously it would be beneficial here because the TRC of the monitor has been incorrectly set to unmodified 2.2 gamma. This means a non-linear TRC will have to be written into the GPU LUTs in order to comply with sRGB. That clearly goes against the idea of having a hardware calibrated monitor. Surely you'd agree? Otherwise, what is the point of 'hardware calibration'?
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Nov 12, 2018
02:54 AM
https://forums.adobe.com/people/D+Fosse wrote richardj21724418 wrote Correct me if I'm wrong but I believe the sRGB linear section extends to between 10 and 11 in terms of 8-bit values. No way. Without recalling exactly where it is - that's not possible. The flat section is a clipping point. All information stops there! Are you suggesting the linear section doesn't extend to levels 10 to 11? If so, why does it need a gamma of 2.4 in order to 'catch up'? Or are you suggesting it's not possible to observe the difference between level 0 and level 5 and 5 and level 10 on an sRGB screen? Hmm! Come on, just emulate it in Photoshop. Create a B&W image in sRGB space. Then assign the profile to AdobeRGB (which has a single gamma of 2.2). It's obvious the TRCs are very different. It's not just in the 'cliiping point'! https://forums.adobe.com/people/D+Fosse wrote With display color management any differences in tone response curves are remapped. You don't see them! The net result that you see on screen is gamma 1.0. You can work with ProPhoto at gamma 1.8, and a monitor calibrated to 2.2, and you don't see that difference because it's remapped. The same with the sRGB curve. I feel you have a problem in your BenQ software, and you think you have found the explanation for it. But you haven't. Whatever it is, it's something else. In short, you're wasting energy on this. You should be looking elsewhere. You appear to think that all monitors should be treated as uncalibrated devices and that colour management can only be performed within the PC, by a combination of device profiles and, in the case of a monitor, TRCs contained in the GPU's. Why then do some monitors offer internal hardware calibration and colour space emulation modes? What's the point? Yes, I do feel there's a problem with the BenQ. It's not just the user calibration software though (which uses Palette Master Element) but it's also the factory calibration of the sRGB mode, which doesn't appear to support the sRGB TRC. I believe there are several issues with PME. I think you're right about wasting energy on it though. I was originally looking for an answer as to whether it seemed acceptable for a premium grade hardware calibrated monitor to be using a single 2,2 gamma curve for its sRGB mode. It seems you think it is. I don't. I guess we'll have to just disagree on that!
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Nov 12, 2018
01:46 AM
https://forums.adobe.com/people/D+Fosse wrote richardj21724418 wrote I don't get this hang up about the "color managed environment". By that I mean any color managed process, any color managed display chain from document profile into monitor profile. I get that, but I don't see it makes a difference if you remove the monitor profile conversion from the PC and place it in the monitor. Done properly, it should amount to the same thing. Arguably it's better placed in the monitor as you don't have the bottleneck of the 8-bit/10-bit link. https://forums.adobe.com/people/D+Fosse wrote The other point I'm trying to make is that monitor black is never deep enough for the sRGB linear black toe to even become a consideration. No monitor can display RGB 0-0-0. The native black point is much higher. The monitor can't display pure black. So that's where "Black Point Compensation" comes in. Instead of just cutting off near black, which would result in visual black clipping on screen, the curve is gently tapered off to monitor black point. This retains full shadow separation on screen, all the way down. But this is much higher than the sRGB flat linear section. Correct me if I'm wrong but I believe the sRGB linear section extends to between 10 and 11 in terms of 8-bit values. However, the linear section still influences the rest of the tonal curve, which I believe requires a gamma of about 2.4 in order to 'catch up'. This means it affects all tonal levels, not just the shadows (although there is a crossover point, perhaps around 100 - I'll let you do the maths!). For instance, an 8-bit sRGB of 30 is about 35 with a pure 2.2 gamma curve. I think you'd agree, sRGB 30 is sufficiently above 'monitor black' to be plainly visible. In order to obtain the same output with a monitor setup with a pure 2.2 gamma curve I'd need to supply it with a value of 35. The difference is very apparent. It not only affects the shadows but also the mid range contrast (because at that point sRGB gamma is 2.4, rather than the flatter 2.2). Rather than theorise about it ad infinitum, simply try it! Emulate it in Photoshop. I guess I've the 'luxury' of having a monitor incorrectly calibrated to sRGB with a pure 2.2 gamma curve. It's therefore easier for me to investigate the issue and experiment. From what I've observed I'm convinced the monitor has been setup with the same 2.2 gamma curve for sRGB mode as for AdobeRGB. It stacks up with switching between modes. It stacks up with Photoshop simulation. It stacks up with nobbling the sRGB standard profile and changing the TRC to a single 2.2 gamma curve. On the basis of the evidence I'm sure a jury would convict, probably unanimously!
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Nov 12, 2018
12:50 AM
https://forums.adobe.com/people/D+Fosse wrote In theory you're right. In practice the sRGB emulation is setting the primaries very accurately, but doesn't bother with the tone curve. And honestly - why should it? Because otherwise the TRC has to be handled by the LUTs in the GPU. Depending on the GPU this may be 10-bit output, it may be 8-bit dithered to 10-bit or it may be 8-bit. However it's done, it's not going to be better that doing it in the monitor. A properly calibrated monitor should have a linear TRC written into the LUT in the GPU and therefore not introduce any 'stepping'. Surely the TRC is the easy part anyway, compared with the colour space conversion? Please forgive my ignornance and naivety. I'm just a common sense kind of guy and not up with you brainy theory types! However, it seems to me you either take a non-standard device and create a custom profile to describe the character of that device, or you take a standard profile and adjust the character of that device to meet the profile. You're doing the latter when you calibrate a monitor to sRGB. If you have a wide gamut native monitor that encompasses all of sRGB space it means that every point in sRGB space will have an optimal associated value in native space. It's 'simply' a matter of translating every one of those 1024x1024x1024 (10-bit component) possible sRGB input values to the native value. Job done! The monitor should then behave as an sRGB device and the correct monitor profile will be the standard sRGB profile. If you need to create a non-standard profile then the monitor hasn't been calibrated correctly to sRGB. It seems odd to calibrate the monitor to meet a standard colour space and then repeat the process to calibrate the PC to the monitor (when you already know the PC LUTs should be linear and the profile should be sRGB).
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Nov 11, 2018
11:15 PM
I don't get this hang up about the "color managed environment". With a monitor with internal hardware calibration it's still a color managed environment. Properly implemented it's the same structure, just the colour space conversion and TRC LUTs are moved out of the computer and into the monitor. What's the problem with that? The calibration/characterisation process is directed to changing parameters in the monitor, rather than the computer, but the outcome should be the same. I don't believe ICC specify where the colour space conversion and TRC should physically take place. It really shouldn't matter. Of course, if it's poorly implemented you may be able to improve results by inserting yet another layer of conversion and TRC LUTs, but it really shouldn't be necessary. Would you argue you should have two stages of profile conversion and TRC LUTs in the computer; the first one for one calibration device, followed by a second for a superior calibration device? No, it's nonsense! What's the conceptual difficulty with hardware calibration? Suppose early monitors had been done that way. Now, in order to save cost, manufacturers come out with uncalibrated monitors and say it can all be done in the PC. I guess they'd be people arguing that wasn't right!
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