Re: Monitor Uniformity study
Re: Monitor Uniformity study
- Subject: Re: Monitor Uniformity study
- From: Refik Telhan via colorsync-users <email@hidden>
- Date: Thu, 13 Feb 2020 00:24:07 +0300
- Thread-topic: Monitor Uniformity study
Hi Danny,
Thanks for the clarification. Now it is making sense.
As I understand it, of all the three tables on the left side of page 2 of
ASUS’s report only the one in the middle is actually specified in ISO 12646. To
bridge the gap between this table and the Tone Uniformity table of BabelColor
CT&A ISO 3664+ report, should ASUS display the values as percentages? For
example, should the value for Box #1 (Top Left) be displayed as 2.23% instead
of 0.0223?
Best,
Refik
--------------------------------------------------------
Refik Telhan, EE B.Sc.
Light and Color Management Consultancy
UNIQ B2 Blok,
Kat:5, Ic Kapi No: 605, Ofis No: TT02-AA23
Maslak Ayazaga Caddesi No:4, Huzur Mahallesi
Sariyer, Istanbul, Turkey
Mobile: + (90) (532) 426 21 87
--------------------------------------------------------
From: Danny Pascale <email@hidden>
Date: 12 February 2020 Wednesday 18:04
To: "email@hidden" <email@hidden>, <email@hidden>
Subject: Re: Monitor Uniformity study
Hello Refik,
The graphs in the ASUS report linked by Roger Breton correspond to Sections
4.2.2 and 4.2.3 of ISO 12646:2015.
The titles of these sections in the standard are confusing but the computation
is clear:
Titles of report:
4.2.2 Evaluation of tone uniformity
4.2.3 Tonality Evaluation (Uniformity)
are really described as being:
4.2.2 Color Uniformity (DeltaE00 from center patch)
4.2.3 Tone uniformity (Mid grey(127)/White(255) ratio deviation from center
patch)
This is what is shown in the ASUS report and in BabelColor CT&A ISO 3664+ tool
Note: CT&A ISO 3664+ tool combines many standards and various versions of these
standards, of which ISO 12646 had many between the 2008 version and the latest
2014-2015 version.
HOWEVER, the Tone uniformity should NOT be done at three grey levels. It is
defined only for the Mid grey(127)/White(255) ratio.
This is what is done in CT&A and in the middle-left graph of the ASUS report.
You will note that the top-left graph of the ASUS report does what looks like a
White(255)/White(255) ratio which is always equal to one (1) and the DEVIATION
is ZERO for all positions. This is redundant and useless.
The data in the bottom left graph looks like it is based on a Dark
grey(63)/White(255). This is not fundamentally wrong but it is not specifically
required in the standard.
Danny Pascale
email@hidden
www.babelcolor.com
On Wed, 12 Feb 2020 12:25:19 +0300, Refik Telhan via colorsync-users
<email@hidden> wrote:
Hi Roger,
I have seen measurements of uniformity in done in a variety of ways on
different reports. Below are the factory reports of two BenQ monitors:
https://reflight-my.sharepoint.com/:i:/g/personal/rtelhan_reflight_onmicrosoft_com/EZmTdVPTlvpPh7y-OklIg6sBcAkY_u1TN6hjkbT55SX5Ig?e=qHcMOh
https://reflight-my.sharepoint.com/:i:/g/personal/rtelhan_reflight_onmicrosoft_com/EUEmL5t2ItNApvEX4pTjXc0BeeweZPJMdTZCi0JbJwGnBQ?e=bMlvB5
The ASUS report is not specifiying the type of the uniformity measure.
BabelColor’s ISO 3664 Test Report for Color Monitor reports a “Tone Uniformity”
calculated as the percentage deviation from the center point’s Gray/White ratio.
This is all too confusing. Another source of confusion is the reliability of
these reports. I have tried to replicate at least some of the mesurements in
the above reports. They were off the target considerably.
These reports should be more specific about what they measuring.
Best,
Refik
On 12.02.2020 04:23, "colorsync-users on behalf of Roger Breton via
colorsync-users" wrote:
The world of high end monitors is changing?
I stumbled on this "Color Calibration Report" from some Taiwanese
manufacturer:
https://1drv.ms/b/s!AkD78CVR1NBqkt8MK5418QlCEBbkHA?e=tAYocf
I'm shocked by the data shown in Page 2, especially the brightness
uniformity; it's all "0.000", at every 25 positions? And the Color
Uniformity barely crosses over the 1 DeltaE mark. Are today's monitors that
good? For a relatively low price, I mean, under $1,000 USD, compared to the
more "respected brands"?
/ Roger
-----Original Message-----
From: Andrew Rodney
Sent: Tuesday, February 11, 2020 12:15 PM
To:
Subject: Re: Monitor Uniformity study
Here you go,
Andrew
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