The joys of the emerging range of wide gamut monitors.

On Tue, 13 Jun 2017 20:52:36 +1200, Eric Stevens wrote:


I've now got it sorted and both monitors look the same. More to follow
tomorrow - a valuable lesson for all and sundry. Well sundry anyway.


Well? ;-)

--
croy

On Fri, 16 Jun 2017 18:38:57 -0700, croy
wrote:

On Tue, 13 Jun 2017 20:52:36 +1200, Eric Stevens wrote:


I've now got it sorted and both monitors look the same. More to follow
tomorrow - a valuable lesson for all and sundry. Well sundry anyway.


Well? ;-)

Well it sometimes seems as though tomorrow never comes. It finally did
a few hours ago. I have written further down what I responded to Dell.

By way of explanation, the Dell monitor concerned employs an internal
Look Up Table (LUT) for color calibration rather than relying on an
ICM file in Windows to profile the monitor. In fact the monitor comes
with preset calibrations for:

AdobeRGB
sRGB
Rec709
DCI-P3
Cal1
Cal2

Cal1 and Cal2 are free to be calibrated to whatever color space the
user wants.

Dell supplies color profiling software 'Dell UltraSharp Color
Calibration System' (DUCCS) which is intended to work with an X-Rite
I1 Display Pro sensor. The DUCCS software is written by Dell and
appears to be a plug-in or similar to X-Rite software. I have
purchased an I1 Display Pro and have run it both with the X-Rite
software (which only produces an ICM file in Windows) and DUCCS. I was
having an enormous amount of trouble with DUCCS which is how I became
involved with the second tier of Dell technical support.

Here beginneth what I wrote to DEll:
========================================
I have successfully calibrated both monitors and I thought I would
write you a short report about what I have done.

I now have everything going. Cal-1 is Native on both screens and Cal-2
is AdobeRGB. I have used Windows Photo Viewer to simultaneously put up
the same raw image side by side on both screens and compared them. I
cannot see any differences. Cal-1 (native) is a slightly wider gamut
than Cal-2 (Adobe RGB). I was interested to notice that the colors of
Cal-2 were not quite the same as the screens' AdobeRGB setting.
However when I used the I1 Profiler software (not DUCCS) to establish
an AdobeRGB profile for the AdobeRGB setting there was only one color
patch on one screen for which the calibrated version visibly differed
(and then only slightly) from that of the AdobeRGB setting in the
screen.

I attribute my initial problems to three major factors:

1. I did not fully understand what DUCCS was doing. In particular
I did not at first understand why a screen calibrated by an internal
Look Up Table (LUT) should also require an external ICM color profile.
This may have led me to do inappropriate things with the settings in
Windows Color Management. I hope I have corrected this and I will
discuss it further below.

2. As you suggested, I may have had problems in Windows. It was
only after I ran ‘sfc /scannow' (as an administrator) and found
several errors that I was able to consistently calibrate both screens.

3. DUCCS has problems which don't help the novice user (and it
has several other problems as well). I will discuss these below.

My Understanding of what DUCCS is doing.
-----------------------------------------------------
Even if the UP2516D has its own color management under the control of
its LUT it is not possible to leave all color management entirely to
this. First, in the absence of a monitor color space the computer's
color management is liable to output an image anywhere from sRGB to
ProPhoto and the monitor will have no particular idea of what to do
with it. Second, even if it is possible to calibrate Cal1 and Cal2 to
correctly display a particular color output from the computer the
preset AdobeRGB, sRGB etc will not be able to cope with a color space
other than that for which they were calibrated. For this reason it is
necessary to assign an all-purpose color space to the UP2516D so as to
give a uniform input with which the various preset settings can
work properly. This is the UP2516D.ICM to be found under ‘profiles' in
Windows color management. No doubt you will tell me if I am wrong in
my understanding.

I did not initially understand any of this and every time I calibrated
(say) Cal2 on screen 1 I would save a file DELL1Cal2.ICM. Certainly I
was confused and probably so was Windows. I now have only the one
UP2516D.ICM.

I cannot emphasize too much my belief that I would have been
considerably helped by a simple explanation of how the color
calibration worked. This should also make clear that the factory
presets cannot be recalibrated (if that is indeed the case).

Problems of DUCCS
-------------------------
I still have no understanding of what it is that generates the notice

"Could not set the display default luminance.
Error communicating with display.
Please verify USB connection"

However, I did notice that when the color patches first appeared,
after clicking the right arrow to go to ‘next' (measure), when the
button under the color patches appeared it would take a short time to
react and then say something about being ‘unable to detect the
screen'. After a more noticeable time delay it would then announce
‘Measure'. I learned to ignore the initial warning and wait for the
final ‘Measure'. Some of my problems may have been caused by me
reacting to the ‘unable to detect screen' message without realising
that I should wait a few more seconds.

There is a problem with what may be a section of the software written
by X-Rite. When one opens DUCCs in advanced mode and clicks on
‘Profile' the screen changes to display a color diagram with triangle
marking out the gamut of the color space. This can display colors and
the color space in x,y coordinates or u',v' coordinates. The color
space triangle changes according to the selection within the ‘RGB
Primaries' tab alongside. There is something very wrong with the
software governing this diagram. The gamut of ‘native' is shown as the
same as that of ‘sRGB'. This is definitely wrong. The gamut of
‘AdobeRGB' is shown as greater than ‘DCI-P3' and I think this may be
wrong also. One can get all kinds of strange results by switching up
and down through the selections and at the same time switching back
and forward between x,y and u',v'. Someone should have a good look at
this.
============================================

I am using both screens with their native color space and the view is
magnificent :-). Even AdobeRGB looks slightly dull in comparison and
as for sRGB ... . I now wonder how we put up with sRGB. As I recently
didn't quite write in another article 'The future is coming and it is
wider gamut color spaces'. I'm sure some of you already know that.

Reviews of the Dell and other screens using similar high-gamut
technology are hihly critical of quality including uneven colour
distributions and uneven backlighting. I only started to encounter
these afte I had bought the first UP2516D and I was very glad that I
had seen no evidence of this kind of thing in the first one that I
bought. It was with trepidation that I bought the second screen but it
too seems to be qually problem free. Maybe Dell (or LG in fact) have
sorted out their problems. Anyway I am now a happy user and I can't
speak too highly of the help I got from Dell.

I'm not so happy with the DUCCS software but I have learned to
navigate a safe path through its peculiarities. At one stage I wrote
to Dell:

"I notice the screen firmware uses C++ which has been
described as 'Write once, read never' language. There are
obviously errors somewhere in the software and I pity the person
who has to find them."

But it all works.
--

Regards,

Eric Stevens

In article , Eric Stevens
wrote:

I am using both screens with their native color space and the view is
magnificent :-). Even AdobeRGB looks slightly dull in comparison and
as for sRGB ... . I now wonder how we put up with sRGB.

try dci-p3 and you'll wonder how we put up with adobe rgb.

and then there's rec. 2020...

On Sat, 17 Jun 2017 02:16:48 -0400, nospam
wrote:

In article , Eric Stevens
wrote:

I am using both screens with their native color space and the view is
magnificent :-). Even AdobeRGB looks slightly dull in comparison and
as for sRGB ... . I now wonder how we put up with sRGB.

try dci-p3 and you'll wonder how we put up with adobe rgb.

Right now I'm doing the best that the monitors can do, such as it may
be.

and then there's rec. 2020...
--

Regards,

Eric Stevens