A-ha!  I've found a work around. I've tweaked the TRCs in the sRGB Color Space Profile file to be the single 2.199219 gamma found in AdobeRGB1998.  sRGB mode looks a whole lot better now. If I can't convince the brains here that this was the problem, there's absolutely no point in me trying to tell BenQ! ... View more

BTW, I'm not saying there's no ICC colour management.  There is, just the monitor has been calibrated to sRGB and therefore the profile to use is the sRGB standard.  Unfortunately though the Benq does not calibrate to proper sRGB space, because the TRC is wrong.  To correct this would require non-linear TRCs to be written into the GPU LUTs, which defeats the object of having internal hardware calibration. ... View more

thedigitaldog  wrote As to the differences you see, as I stated, it's not supposed to work that way with proper ICC color management. The TRC or Gamma (and they are NOT the same) you calibrate a display for is compensated using Display Using Monitor Compensation, which is why we can use differing working spaces, with differing gamma or TRC encoding and it doesn't at all have to match the display response. It's why for some, calibrating to a Native Gamma is useful. That's the way it works with a device which hasn't been calibrated to a standard colour space, e.g. a typical monitor (one without internal calibration capability).  Then you need fiddle factors, like a custom profile, specific to that device. The point about wide gamut monitors with internal calibration is that they should be able to be configured to emulate other colour spaces, provided they fall within their native gamut.  Typically this is achieved using 3D LUTs.  These are doing more than simply replacing the 1D LUT in the GPUs.  They perform the colour space conversion from the desired colour input space to native monitor space.  If done correctly, it means the monitor can be configured to behave as a pure sRGB device.  If profiled it would be as close as possible to the sRGB standard.  When a monitor is correctly calibrated to AdobeRGB it will be setup with a 2.2 gamma response curve.  When a monitor is correctly calibrated to sRGB is will be setup with the adjusted 2.2 gamma response curve.  If you switch the monitor between AdobeRGB and sRGB modes whilst maintaining the same B&W input it should be possible to see the difference between the response curves.  With the Benq there is no discernible difference between the modes.  The sRGB mode has been setup with the same 2.2 gamma curve.  This is why the shadows are too dark when I apply the sRGB profile to the input data. It seems such a shame to have these lovely internal 3D LUTs and not do the job properly.  I can't imagine NEC and Eizo getting it wrong. ... View more

thedigitaldog  wrote richardj21724418   wrote thedigitaldog    wrote So you’re also calibrating white to 80 cd/m2, black to 0.2 cd/m2? I'm not sure how significant that will be.  I'm actually calibrating to 100 cd/m2, and using the 'Absolute Zero' black point setting in the calibrator (using the 'Relative' tends to cause PME to 'do a wobbly'!). You wrote: However, one of the reasons for having a monitor with internal 3D LUT calibration is surely that you can calibrate the monitor to a standard colour space, such as sRGB? You're not producing sRGB without those specific targets for cd/m^2. And a bit more: sRGB Really, I don't think that is relevant here. If I display a B&W image and switch between the factory calibrated AbobeRGB and sRGB modes (with the same white/brightness/contrast settings and without changing display profile) I can see no change in the shadows, or in the image at all come to that. Is that what you'd expect, given that AdobeRGB and sRGB are supposed to have different gamma curves? ... View more

thedigitaldog  wrote So you’re also calibrating white to 80 cd/m2, black to 0.2 cd/m2? I'm not sure how significant that will be.  I'm actually calibrating to 100 cd/m2, and using the 'Absolute Zero' black point setting in the calibrator (using the 'Relative' tends to cause PME to 'do a wobbly'!). I'm convinced the problem is the monitor sRGB gamma curve being set to 2.2, rather than 'adjusted 2.2'.  What I observe stacks up with that.  When displaying a B&W image, if I change the monitor between AdobeRGB and sRGB modes (without changing profiles) the image looks identical.  This means they are using the same gamma curves, which is not correct.  What should happen in sRGB mode is the monitor should become more sensitive to the shadow levels and they should look lighter (this would of course be compensated for if I switched to the sRGB profile).  As it is, when I apply the sRGB profile to sRGB mode the shadows become too dark. To my mind, if a monitor has 3D LUTs for internal calibration then, with the correct software, it should be possible to program it to properly emulate smaller colour spaces, such as sRGB, without the need for a non-standard profile.  If it still requires use of a non-standard profile in order to display correctly then the monitor hasn't been properly calibrated IMO. ... View more

Hi Gernot & Neil, Thanks for your replies. The numerical difference between the sRGB curve and a single gamma of 2.2 is actually quite significant in the shadows. Using Photoshop you can find the differences between the shadow values with the sRGB gamma and the single gamma of 2.2 used by AdobeRGB (I know this is a crude approach but Photoshop tends to get the numbers right).  In 8-bit mode, in order to obtain the same output as 5, 10 and 20 in sRGB gamma it requires 13, 18 and 27 respectively in 2.2 gamma.  That's quite a difference IMO. I could upload a couple of demonstration images but suggest you try it yourself.  Create a monochrome (B&W) image in Photoshop in sRGB working space.  Then assign (not convert) the profile to AdobeRGB (this assigns a single gamma of 2.2 to an image that is profiled to sRGB gamma).  Note how the shadow areas get darker. This is exactly the effect I'm seeing with a monitor calibrated to a single gamma of 2.2 when using the standard sRGB profile – the monitor requires much larger shadow values than provided by sRGB. With a 'conventional' monitor you calibrate the computer to the monitor, rather than calibrate the monitor directly.  When you do this of course you will need to characterise the monitor output and produce a custom profile for the sRGB gamut.  This means non-colour managed applications still won't display correctly because the monitor isn't a pure sRGB device. However, one of the reasons for having a monitor with internal 3D LUT calibration is surely that you can calibrate the monitor to a standard colour space, such as sRGB?  You should then be able to treat the monitor as a pure sRGB device and use the standard sRGB profile.  This means non-colour managed applications will display correctly. Of course, they'll always be a minor deviation from the ideal device but nothing like I'm seeing.  It's clear from simulation with Photoshop where the problem lies - the monitor gamma is 2.2, not sRGB. Palette Master Element doesn't even provide a characterisation profile following calibration to sRGB or AdobeRGB primaries (it does output a profile, but this is to native space!).  My assumption is they expect you to use the standard sRGB/AdobeRGB profiles, but it’s absolutely hopeless asking Benq customer support! Going back to my original question, would you expect a premium level monitor which has been hardware calibrated to sRGB to use a basic 2.2 gamma?  Even the factory sRGB mode appears to be calibrated to basic 2.2 gamma.  My wife’s modest Dell does a better job of displaying sRGB shadows, but then it is a dedicated sRGB monitor! It's really not something I should be losing much sleep about as I don't normally work in sRGB.  Just I noticed it when trying to sort of print calibrations and wanted to get to the bottom of it, in case it indictaed a problem elsewhere.  I'll just add it to the list of Benq/PME issues. ... View more

In fact, Palette Master Element doesn't inspire confidence when it offers users to set gammas other than 2.2 for AdobeRGB and sRGB calibrations.  If you're calibrating to a standard colour space I don't see there should be options for deviating from the correct gammas, otherwise they won't be correct for the standard profiles. ... View more

The SW2700PT has internal calibration.  In other words, the calibration process programs the gamma and colour space response curves into the monitor, rather than it being handled by the computer's GPU LUT. If I calibrate the monitor to native mode it's fine (just about!).  And of course, I use this with the profile created for that native calibration. It's also fine with Adobe RGB, using the standard AdobeRGB profile, which has a simple gamma of 2.2. However, the monitor also has a factory calibrated sRGB mode.  In this mode I expect it to behave as a monitor to sRGB specification and to use it with the standard sRGB profile.  But it doesn't because the factory calibration has been performed using a simple gamma of 2.2.  It lacks the linear section contained in the sRGB profile.  This means images appear higher contrast in sRGB mode because the shadows get crushed. Of course, the factory calibration won't be perfect. so it's also possible to calibrate the monitor to sRGB.  However, again this is performed using a gamma of 2.2, without a linear section.  There's no profile file required from the calibration process.  The monitor is calibrated to sRGB via its internal LUTs.  Once calibrated, I thought it should function as close as possible to the sRGB spec and should be used with the standard sRGB profile. ... View more