Re: Monitor calibration & profiling in a multiuser OSX environment.
Re: Monitor calibration & profiling in a multiuser OSX environment.
- Subject: Re: Monitor calibration & profiling in a multiuser OSX environment.
- From: kk_cs <email@hidden>
- Date: Wed, 3 Sep 2003 14:37:59 +0200
In a message dated 9/1/03 1:37:27 AM, email@hidden writes:
If my understanding is correct, the process of recalibrating a monitor
prior to
profiling it changes the behavior of the monitor (hopefully close to
some
standard). Profiling then measures this new state.
I also thought that changing the behavior of the monitor, even a
little, would
would render inaccurate all the previous profiles made for that
monitor.
This is correct. You have to keep apart 2 different methods of
calibrating a monitor.
- hardware calibration changes the behavior of the monitor through the
monitor electronics (CRTs only). Some TFT manufacturers claim they
hardware calibrate their displays, this is untrue. They have a 10bit
LUT in the MONITOR instead on the graphics card, but it still is
software calibration (or maybe you could call it firmware calibration).
- software calibration creates a video LUT and downloads it to the
graphics card.
The first one is preferable, as far as quality goes.
QUESTION 1
If this is true can someone explain to me how having custom monitor
profiles as
a personal user preference in a multiuser system (OSX) is meant to
work?
Surely when any user recalibrates & profiles a monitor, the previously
created
monitor profiles that are still in use by other people for that
particular
monitor will then become inaccurate?
Maybe I have missed something obvious? The location of the monitor
profile under
OS9 made more sense to me from a multiuser point of view.
For this environment, software calibration is the way to go. Quite some
time ago (don4t ask how long, I don4t remember) Apple defined a
"private" tag in the ICC monitor profiles and published it, so that
everybody can create and use it. This tag, called vcgt holds the result
of a software calibration - the video LUTs. ColorSync automatically
detects and downloads these LUTs into the video card. Thus you change
the calibration when selecting a new profile. Profile and calibration
are inseparable and your monitor will always have the right calibration
for the profile.
Windows doesn4t have that automatic mechanism and doesn4t know vcg
tags. basICColor display writes them into the profiles anyway, but uses
its own downloader to extract and download them.
QUESTION 2
Can EyeOne match's default monitor profile saving behavior be changed
to save in
the 'Root(slash) / library / colorsync / profiles' rather than
'~(home)/ library
/ colorsync / profiles' or is this a bad idea?
Doesn4t matter, where the profiles are. The only consequence would be,
that every user can see and use all the profiles - even more confusion
here.
Thanks for you help
Peter Miles
Regards,
Karl Koch
Color Solutions Consulting
Dipl.-Ing. Karl Koch
Falkenstra_e 13
D-82377 Penzberg
phone +49 (0)8856-932505
fax +49 (0)8856-932503
www.basICColor.de
basICColor. is a registered trademark of
Color Solutions Software, Germany
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