Re: Media Testing for maclife.de
Re: Media Testing for maclife.de
- Subject: Re: Media Testing for maclife.de
- From: Uli Zappe <email@hidden>
- Date: Thu, 11 Sep 2008 14:43:58 +0200
Am 11.09.2008 um 12:18 schrieb Bob Frost:
I always understood, but am subject to correction, that they are two
entirely separate processes.
Yes. Simply put, "calibration" puts the hardware into a well-defined,
optimum state. "Profiling" generates a profile that describes this
very state (as far as color is concerned) and its limitations.
Therefore it is crucial to calibrate a hardware device before
profiling it.
When I run iMatch, or BasicColor, or ColorNavigator on my monitors,
it is my understanding that they first 'calibrate' the graphics card
or monitor hardware, and then 'profile' the resulting color,
although I can opt to do just the latter, with no 'calibration'.
Yep, since usually monitors don't have the means to calibrate
themselves, monitor profiling packages offer calibration, too.
Printers and scanners, OTOH, usually auto-calibrate when you turn them
on, or after a certain amount of usage time. Therefore, you won't see
printer or scanner profiling software offer a calibration.
There's a simple but crucial difference between the effects of
calibration and profiling. Since calibration changes *hardware*
settings, it affects *all* software using this device, color managed
or not. For instance, changing the gamma value or white balance of a
monitor (which is done during calibration) affects the visual output
of any software, color managed or not.
OTOH, profiling this monitor will show an effect only within color-
management aware apps.
What I don't fully understand is the 'calibration' of a camera.
It's mainly setting the white balance, just as with a scanner (that
upon being switched on, moves its sensor to a patch of white to
properly white balance itself). Of course, the difference to a scanner
is that you have to white balance every single shot as the
illumination constantly changes.
Other than that, the camera, just like a scanner or printer, might
perform some internal calibration routines when being switched on. For
instance, you might argue that the sensor cleaning now often performed
by cameras when being switched on is part of such an internal
calibration.
Uli's work seems to be just concerned with 'profiling', not
'calibration'?
Yes. I never said anything else.
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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