Re: Ooops - D65 != D65 ???
Re: Ooops - D65 != D65 ???
- Subject: Re: Ooops - D65 != D65 ???
- From: Uli Zappe <email@hidden>
- Date: Wed, 20 Jun 2007 06:18:17 +0200
Am 19.06.2007 um 21:21 schrieb email@hidden:
In a message dated 6/18/07 4:35:04 PM, email@hidden writes:
I haven't found a package yet that would tell me the native
whitepoint of my display explicitly in numbers
Spyder2PRO's info window will tell you your monitor's native, and
calibrated, whitepoints numerically, including xy and Kelvin. It
also allows you to target a whitepoint by either xy or Kelvin...
Sorry for overlooking that - you are right! I wrote this just a few
hours after I had received the Spyder, and in my first tests I
concentrated on creating profiles, using mostly the software's main
window. Since this is a wizard-like interface just like Eye-One
Match, it just didn't occur to me that - unlike Eye-One Match - there
are additional menu entries that will reveal additional functionality.
There are a few minor glitches in the software and the documentation,
but generally, this is an all-important step forward from the Eye-One
Match software which misses all these analytical features. Contrary
to the Eye-One, I feel I have a chance to *know* what I'm doing -
nice! :-) And the much better documentation of the Spyder fits in
nicely with this, as well.
But two questions, David. You wrote:
Spyder2PRO's info window will tell you your monitor's native [...]
whitepoints
Where does the software get that info from?
I ask because when I first opened the Info window, it told me that
the "uncalibrated" (= native) whitepoint of my display is 0.314 -
0.342. At that time, I had not yet used Spyder2Pro to create a
profile with a "native whitepoint" setting (I did use it to create
profiles with a D65 setting). After I created a profile with a
"native whitepoint" setting, the Info panel reported the
"uncalibrated" (= native) whitepoint of my display is 0.311 - 0.338.
So at first I thought the Spyder software gets this info from the
hardware (Apple's System Profiler, whatever) as it "knew" it
immediately, but in this case a measurement couldn't change that. So
can you tell me where Spyder gets this info from?
including xy and Kelvin
When I enter 6500 Kelvin in the "user-defined whitepoint" [translated
from the German GUI] dialog panel, the panel displays an xy of
0.314 / 0.324. Robin Myers said at the beginning of this thread that
D65 is defined as 0.3127 / 0.329, which is also what Eye-One Match
reports for 6500 Kelvin in its corresponding dialog panel. Now where
does that inconsistency come from?
But, anyway - now that I have a chance to actually measure it, I can
report what the various devices regard as D65 = 0.314 / 0.324 or
0.3127 / 0.329 (of course the Spyder is consistent to itself, so the
results below don't tell which device is "objectively" right, but
rather the difference *between* the devices)
Eye-One Display: 0.315 0.341 6316 K
Eye-One Pro: 0.314 0.333 6407 K
huey: 0.307 0.328 6836 K
Spyder2Pro: 0.313 0.325 6510 K
(0.311 0.321 6657 K with ICC v4; is the
chromatic adaptation transformation lossy?)
(Kelvin calculated by entering the xy results into Spyder's "user-
defined whitepoint" dialog panel)
So, according to the Spyder ;-) the Spyder comes close, both Eye-Ones
have too much y to varying degrees, and the huey is just faaaar off
with x.
Robin Myers said at the beginning of this thread:
If you are getting some variability in the third decimal place
between instruments then it might be alright, depending on the
amount. If you are only getting repeatability to the second decimal
place, then something is terribly wrong with the instruments, the
display, or both.
As the above shows, there's not even repeatability to the second
decimal place, so something *is* terribly wrong - that's why I
started this thread ;-) (But note that there *is* repeatability
+-0.001 for each device in itself!)
I also performed tests with a "native whitepoint" setting (apart from
the huey, which does not have such a setting), which at that time
Spyder's Info window reported to be 0.311 / 0.338
Eye-One Display: 0.309 0.337
Eye-One Pro: 0.310 0.337
Spyder2Pro: 0.310 0.337
So here the results are basically consistent. I still don't know
enough about all this, but I *assume* that a "native whitepoint"
setting basically just means *omitting* a calibration step, and if
the issue happens during this step, it's clear why this setting will
work. :-)
Bye
Uli
________________________________________________________
Uli Zappe, Solmsstraße 5, D-65189 Wiesbaden, Germany
http://www.ritual.org
Fon: +49-700-ULIZAPPE
Fax: +49-700-ZAPPEFAX
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