Calibrator correction for Eye One Display 2 & GB-LED Backlight LCD Monitor?

[Al Robertson]

Hi all,



I am currently using an Eye One Display 2 colorimeter with the latest
argyllCMS and dispcalGUI to calibrate a NEC MultiSync LCD1990SXi graphic
arts monitor. I'm very pleased with the results-THANK YOU! I'm a photo
enthusiast/home user and appreciate good color, but have a hobbyist's budget
and reasonable expectations.



The NEC has become dim over time and I'm looking to replace it soon with an
Asus ProArt PA249Q which, like the better known Dell U2413, has the LG
LM240WU9-SLA1 AH-IPS panel. But I have one problem.



This relatively new panel has a GB-LED backlight (improved gamut), but from
what I've read, the curves are sufficiently different that I would need to
either go buy a new calibrator (X-Rite wanted to sell me the i1Display Pro -
$229), or get a new correction matrix to successfully use my existing
colorimeter.



I checked dispcalGUI's Colorimeter Corrections Database, etc. and found some
CCSS and CCMX files for the Dell U2413, but none that support the Eye One
Display 2.





QUESTIONS.



Does anyone have a corrections file for the Eye One Display 2 and a GB-LED
backlight display? Or perhaps be thinking about either making one, or
including GB-LED support into argyllCMS/dispcalGUI as a new mode?



If not, any ideas on how to make or fake one at home?



One idea.The monitor claims to come factory calibrated within 3 delta E
(fingers crossed.) Is there at least a way to make a correction file that
uses the factory calibration as a trusted baseline so I can always get back
to that even if the colors drift over time (or if I want to customize the
calibration)?





Thanks very much in advance for any help!

-Al

[Graeme Gill]

Al Robertson wrote:

Hi,

Post by Al Robertson
The NEC has become dim over time and I'm looking to replace it soon with an
Asus ProArt PA249Q which, like the better known Dell U2413, has the LG
LM240WU9-SLA1 AH-IPS panel. But I have one problem.
This relatively new panel has a GB-LED backlight (improved gamut), but from
what I've read, the curves are sufficiently different that I would need to
either go buy a new calibrator (X-Rite wanted to sell me the i1Display Pro -
$229), or get a new correction matrix to successfully use my existing
colorimeter.

The i1Display Pro is a pretty solid instrument, and well worth
the investment.

Post by Al Robertson
Does anyone have a corrections file for the Eye One Display 2 and a GB-LED
backlight display? Or perhaps be thinking about either making one, or
including GB-LED support into argyllCMS/dispcalGUI as a new mode?

The variability of the instrument is such that I'd be a bit suspicious
of a correction matrix made for a different instance of the i1d2.

Post by Al Robertson
If not, any ideas on how to make or fake one at home?

The best way of course is to use a spectrometer (ie. i1pro or ColorMunki spectro.)
as a reference on your display against your i1d2.

Post by Al Robertson
One idea.The monitor claims to come factory calibrated within 3 delta E
(fingers crossed.) Is there at least a way to make a correction file that
uses the factory calibration as a trusted baseline so I can always get back
to that even if the colors drift over time (or if I want to customize the
calibration)?

OK, here's an outline of how you might go about this. I'm
leaving out some details, and I haven't actually tried it,
so you may well need to troubleshoot the procedure:

Create a reference test set of (say) a 3^3 or 4^3 cube set using
targen, ie. something like:

targen -v -d3 -e0 -B0 -m3 -f0 test

Copy this to a reference set:

copy test.ti1 ref.ti1

Set your new display to (say) sRGB mode, and measure the
test set with your instrument.

dispread -v -yl test

Create a reference set using the sRGB.icm file, that we
assume the new display is calibrated to:

fakeread -v sRGB.icm ref

A problem with this is that the real readings will be
returned to absolute values (cd/m^2), whereas the fakeread
values are normalised to 100, so we will have to make sure
that the fakeread values get scaled the same way.

Open the test.ti3 file in a text editor and copy the
LUMINANCE_XYZ_CDM2 line, ie. for the sake of an example:

LUMINANCE_XYZ_CDM2 "46.509281 49.445099 45.615122"

into the ref.ti3 file in a similar position. This should
cause the values to be scaled to match the instrument values.

Create a ccmx correction matrix from the ref and test results:

ccxxmake -v -f ref.ti3,test.ti3 correction.ccmx

You can then use the correction matrix with your instrument
on that display, ie.

dispread -yl -X correction.ccmx etc.

Graeme Gill.

[Al Robertson]

Dear Graeme,

Thank you very much for your detailed reply. I appreciate your time.

Good news - I found a lab at work willing to lend me an i1Pro. I'll order
the monitor now that I have a plan to calibrate it. I can calibrate it once
with the i1Pro, and also create a colorimeter correction for my specific
i1D2. Then I can calibrate it with the i1D2 and compare the result with the
first calibration to confirm the accuracy of the new correction file. This
seems to offer a good chance of success.

Best regards,
Al

-----Original Message-----
From: argyllcms-bounce-***@public.gmane.org [mailto:argyllcms-bounce-***@public.gmane.org]
On Behalf Of Graeme Gill
Sent: Wednesday, September 4, 2013 10:51 PM
To: argyllcms-***@public.gmane.org
Subject: [argyllcms] Re: Calibrator correction for Eye One Display 2 &
GB-LED Backlight LCD Monitor?

Al Robertson wrote:

Hi,

Post by Al Robertson
The NEC has become dim over time and I'm looking to replace it soon
with an Asus ProArt PA249Q which, like the better known Dell U2413,
has the LG
LM240WU9-SLA1 AH-IPS panel. But I have one problem.
This relatively new panel has a GB-LED backlight (improved gamut), but
from what I've read, the curves are sufficiently different that I
would need to either go buy a new calibrator (X-Rite wanted to sell me
the i1Display Pro - $229), or get a new correction matrix to
successfully use my existing colorimeter.

The i1Display Pro is a pretty solid instrument, and well worth the
investment.

Post by Al Robertson
Does anyone have a corrections file for the Eye One Display 2 and a
GB-LED backlight display? Or perhaps be thinking about either making
one, or including GB-LED support into argyllCMS/dispcalGUI as a new mode?

The variability of the instrument is such that I'd be a bit suspicious of a
correction matrix made for a different instance of the i1d2.

Post by Al Robertson
If not, any ideas on how to make or fake one at home?

The best way of course is to use a spectrometer (ie. i1pro or ColorMunki
spectro.) as a reference on your display against your i1d2.

Post by Al Robertson
One idea.The monitor claims to come factory calibrated within 3 delta
E (fingers crossed.) Is there at least a way to make a correction file
that uses the factory calibration as a trusted baseline so I can
always get back to that even if the colors drift over time (or if I
want to customize the calibration)?

OK, here's an outline of how you might go about this. I'm leaving out some
details, and I haven't actually tried it, so you may well need to
troubleshoot the procedure:

Create a reference test set of (say) a 3^3 or 4^3 cube set using targen, ie.
something like:

targen -v -d3 -e0 -B0 -m3 -f0 test

Copy this to a reference set:

copy test.ti1 ref.ti1

Set your new display to (say) sRGB mode, and measure the test set with your
instrument.

dispread -v -yl test

Create a reference set using the sRGB.icm file, that we assume the new
display is calibrated to:

fakeread -v sRGB.icm ref

A problem with this is that the real readings will be returned to absolute
values (cd/m^2), whereas the fakeread values are normalised to 100, so we
will have to make sure that the fakeread values get scaled the same way.

Open the test.ti3 file in a text editor and copy the
LUMINANCE_XYZ_CDM2 line, ie. for the sake of an example:

LUMINANCE_XYZ_CDM2 "46.509281 49.445099 45.615122"

into the ref.ti3 file in a similar position. This should cause the values to
be scaled to match the instrument values.

Create a ccmx correction matrix from the ref and test results:

ccxxmake -v -f ref.ti3,test.ti3 correction.ccmx

You can then use the correction matrix with your instrument on that display,
ie.

dispread -yl -X correction.ccmx etc.

Graeme Gill.

[Milan Knížek]

Hi Graeme,

thanks for the write up a year ago, I could have saved some time if I
found it earlier ;-)

One question forcing me to revive the old topic though: you mentioned
that

x "fakeread values are normalised to 100"

x meaning that dispread values are not normalised to 100

and therefore the LUMINANCE_XYZ_CDM2 should be copied from dispread
test.ti3 to fakeread ref.ti3 file.

My confusion stems from the test.ti3 (produced by dispread), which reads
that the numbers _are_ normalised:

KEYWORD "LUMINANCE_XYZ_CDM2"
LUMINANCE_XYZ_CDM2 "66.758160 61.640342 95.172183"
KEYWORD "NORMALIZED_TO_Y_100"
NORMALIZED_TO_Y_100 "YES"
...
BEGIN_DATA
1 100.000 100.000 100.000 108.303 100.000 154.399
...


Is your hint re. copying of LUMINANCE_XYZ_CDM2 values from test.ti3 to
ref.ti3 still valid nowadays?


BTW, my vendor tailored Huey for Samsung SyncMaster XL20 seems broken
(all of sudden there is too much green after calibration), hence I had a
similar idea as the original poster to re-use my Eye-one Display 2 and
rely on Samsung's emulated sRGB to create the correction matrix.

I may end up buying a new monitor anyway, just giving it a try. The
first impression is that the correction matrix works - I use it for
profiling in "custom mode / native colour space" of the display.

regards,
Milan
--
http://milan-knizek.net/
About linux and photography (Czech only)
O linuxu a fotografování

Post by Graeme Gill
Hi,

Post by Al Robertson
The NEC has become dim over time and I'm looking to replace it soon with an
Asus ProArt PA249Q which, like the better known Dell U2413, has the LG
LM240WU9-SLA1 AH-IPS panel. But I have one problem.
This relatively new panel has a GB-LED backlight (improved gamut), but from
what I've read, the curves are sufficiently different that I would need to
either go buy a new calibrator (X-Rite wanted to sell me the i1Display Pro -
$229), or get a new correction matrix to successfully use my existing
colorimeter.

The i1Display Pro is a pretty solid instrument, and well worth
the investment.

Post by Al Robertson
Does anyone have a corrections file for the Eye One Display 2 and a GB-LED
backlight display? Or perhaps be thinking about either making one, or
including GB-LED support into argyllCMS/dispcalGUI as a new mode?

The variability of the instrument is such that I'd be a bit suspicious
of a correction matrix made for a different instance of the i1d2.

Post by Al Robertson
If not, any ideas on how to make or fake one at home?

The best way of course is to use a spectrometer (ie. i1pro or ColorMunki spectro.)
as a reference on your display against your i1d2.

Post by Al Robertson
One idea.The monitor claims to come factory calibrated within 3 delta E
(fingers crossed.) Is there at least a way to make a correction file that
uses the factory calibration as a trusted baseline so I can always get back
to that even if the colors drift over time (or if I want to customize the
calibration)?

OK, here's an outline of how you might go about this. I'm
leaving out some details, and I haven't actually tried it,
Create a reference test set of (say) a 3^3 or 4^3 cube set using
targen -v -d3 -e0 -B0 -m3 -f0 test
copy test.ti1 ref.ti1
Set your new display to (say) sRGB mode, and measure the
test set with your instrument.
dispread -v -yl test
Create a reference set using the sRGB.icm file, that we
fakeread -v sRGB.icm ref
A problem with this is that the real readings will be
returned to absolute values (cd/m^2), whereas the fakeread
values are normalised to 100, so we will have to make sure
that the fakeread values get scaled the same way.
Open the test.ti3 file in a text editor and copy the
LUMINANCE_XYZ_CDM2 "46.509281 49.445099 45.615122"
into the ref.ti3 file in a similar position. This should
cause the values to be scaled to match the instrument values.
ccxxmake -v -f ref.ti3,test.ti3 correction.ccmx
You can then use the correction matrix with your instrument
on that display, ie.
dispread -yl -X correction.ccmx etc.
Graeme Gill.

[Graeme Gill]

Post by Milan Knížek
x "fakeread values are normalised to 100"
x meaning that dispread values are not normalised to 100

Hi,
actually with the current code dispread can return either
normalized (default) or non-normalized values (-w flag).
This is marked in the resulting .ti3 by the
NORMALIZED_TO_Y_100 YES/NO value.

Post by Milan Knížek
My confusion stems from the test.ti3 (produced by dispread), which reads
KEYWORD "LUMINANCE_XYZ_CDM2"
LUMINANCE_XYZ_CDM2 "66.758160 61.640342 95.172183"
KEYWORD "NORMALIZED_TO_Y_100"
NORMALIZED_TO_Y_100 "YES"

ccxmake will take either case and restore the absolute
values for computing the correction matrix.

Since the fakeread output doesn't have the information
needed for this to happen, you would have to add this,
by adding the LUMINANCE_XYZ_CDM2 value and
NORMALIZED_TO_Y_100 "YES" so that it too can be
converted back to absolute by ccxxmake.

Post by Milan Knížek
Is your hint re. copying of LUMINANCE_XYZ_CDM2 values from test.ti3 to
ref.ti3 still valid nowadays?

Yes, since I haven't added the code to fakeread to read the ICC
SigLuminanceTag and use that to set a LUMINANCE_XYZ_CDM2 value,
even if it is present in the profile.

Post by Milan Knížek
BTW, my vendor tailored Huey for Samsung SyncMaster XL20 seems broken
(all of sudden there is too much green after calibration), hence I had a
similar idea as the original poster to re-use my Eye-one Display 2 and
rely on Samsung's emulated sRGB to create the correction matrix.

Hmm. Either something has gone wrong with it electrically, or
the filters have aged.

Graeme Gill.

[Milan Knížek]

Thanks for the clarification. Seems to work quite fine, as far as my
eyes can tell... (Definitely no visible colour shift as it appeared w/o
the correction matrix.)

I am about to buy ColorMunki Design soon and plan to re-do the
correction matrix to see how off the use of fakeread with sRGB emulation
of my monitor was.

Milan

Post by Graeme Gill

Post by Milan Knížek
x "fakeread values are normalised to 100"
x meaning that dispread values are not normalised to 100

Hi,
actually with the current code dispread can return either
normalized (default) or non-normalized values (-w flag).
This is marked in the resulting .ti3 by the
NORMALIZED_TO_Y_100 YES/NO value.

Post by Milan Knížek
My confusion stems from the test.ti3 (produced by dispread), which reads
KEYWORD "LUMINANCE_XYZ_CDM2"
LUMINANCE_XYZ_CDM2 "66.758160 61.640342 95.172183"
KEYWORD "NORMALIZED_TO_Y_100"
NORMALIZED_TO_Y_100 "YES"

ccxmake will take either case and restore the absolute
values for computing the correction matrix.
Since the fakeread output doesn't have the information
needed for this to happen, you would have to add this,
by adding the LUMINANCE_XYZ_CDM2 value and
NORMALIZED_TO_Y_100 "YES" so that it too can be
converted back to absolute by ccxxmake.

Post by Milan Knížek
Is your hint re. copying of LUMINANCE_XYZ_CDM2 values from test.ti3 to
ref.ti3 still valid nowadays?

Yes, since I haven't added the code to fakeread to read the ICC
SigLuminanceTag and use that to set a LUMINANCE_XYZ_CDM2 value,
even if it is present in the profile.

Post by Milan Knížek
BTW, my vendor tailored Huey for Samsung SyncMaster XL20 seems broken
(all of sudden there is too much green after calibration), hence I had a
similar idea as the original poster to re-use my Eye-one Display 2 and
rely on Samsung's emulated sRGB to create the correction matrix.

Hmm. Either something has gone wrong with it electrically, or
the filters have aged.
Graeme Gill.