[argyllcms] Re: New Monitor Profile for my old NEC PA271W
- From: <graxx@xxxxxxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Thu, 17 Jun 2021 11:49:23 -0400
I hate to ask but I’m “curious”…
What is the Xn Yn Zn used in the computation of the “Approximate Lab White
point” :
No of test patches = 200
Omitted 0 zero measurements
Estimating white point
Approximate White point XYZ = 1.00689507 0.99653950 0.93805206, Lab =
99.866039 7.850635 -8.986307
Creating optimised per channel curves
Initial White Point XYZ 1.006895 0.996540 0.938052, Lab 99.866039 7.850635
-8.986307
My own, very personal “visual impression” of my display is not “green” as 99.86
7.85 -8.98 would lead me to believe.
Just curious…
Also, since we’re on the subject of white point determination, does colprof
uses some kind of Bradford transformation internally? My own “old” white point
“normalization” gives me, in Excel :
Ti3 XYZ 74.26 73.69 69.11
NormXYZ 1.0078 1.000 0.9379
Not far from yours, Graeme…
BTW, I made some comparative measurements between MYIRO and my CS-200 and found
acceptable agreement (here, in a Copied/Pasted Excel table – hope it goes
through in HTML format):
X
Y
Z
x
y
CCT
MYIRO
74.60
73.69
70.07
0.3416
0.3375
5095
CS-200
76.59
75.96
71.10
0.3425
0.3396
5060
Argyll ti3
74.26
73.69
69.11
0.3421
0.3395
5080
D50
0.3457
0.3585
5001
The first two lines show a fresh set of measurements, made this morning.
The third line represents the data (ti3) that was fed to colprof yesterday.
It may be time to nudge the calibrated white point of my display to D50
chromaticities…
Slightly “yellower”, slightly “redder”.
Best / Roger
From: argyllcms-bounce@xxxxxxxxxxxxx <argyllcms-bounce@xxxxxxxxxxxxx> On Behalf
Of graxx@xxxxxxxxxxxx
Sent: Wednesday, June 16, 2021 8:40 PM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] New Monitor Profile for my old NEC PA271W
I like using argyll, it's a real ICC color profile laboratory 😊
I finally got through measuring my monitor using MYIRO.
For the purpose of "getting my feet wet", I only used the same 200 patches I've
used many times in the past with the i1Pro and my CS200 when doing 'initial
exploration'.
I used this command line :
colprof.exe -v -A"NEC" -M"PA271W" -D"NEC PA271W 200 MYIRO cLUTXYZ (2021 06 16)"
-aX -C"RogerBreton 2021" -O"C:\NEC PA271W MYIRO 200 cLUTXYZ (2021 06 16).icm"
C:\NEC_PA271.ti3
For all my efforts, I got these statistics :
Profile check complete, peak err = 1.470881, avg err = 0.385717, RMS =
0.458764
I think it's quite acceptable?
There are a few things with regards to "white measurements" which I have to
look into but, for the moment, I made the resultant profile the "Default"
Monitor Profile in Windows 10 Color Management and launched Photoshop CC.
Everything seems to look good, so far. I opened up a few sRGB images and I must
say I'm pleased with the results. Haven't look at "torture" test images such as
the (Ed) Granger rainbow... but I don't expect any 'disasters' 😊 Thanks Graeme
Gill!!!
/ Roger
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