BenQ SW2700PT and colour management of hardware calibrated monitors

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.