Re: ColorSync Utility Profiles CMM choice and Profile Flags
Re: ColorSync Utility Profiles CMM choice and Profile Flags
- Subject: Re: ColorSync Utility Profiles CMM choice and Profile Flags
- From: bruce fraser <email@hidden>
- Date: Sat, 24 May 2003 11:57:26 -0700
At 5:45 PM +0100 5/24/03, Nick Walker wrote:
Mac OSX 10.2.6 - Profiles
/library/ColorSync/Profiles - Adobe RGB (1998) Phase One supplied Adobe RGB
(1998) profile. Flags = Best Quality
/library/Application Support/Adobe/Color/Profiles/Recommended/ Adobe RGB
(1998) Flags = Normal quality
Why the different flag qualities is Adobes' Normal' inferior to Phase Ones'
Beset Quality or have Phase One just substituted Adobes term from Normal to
Best for reasons only known to them?
I don't think there's a single current CMM that uses the "quality"
flag, which was specific to early implementations of ColorSync that
allowed CMMs to choose different degrees of precision to trade speed
for quality. Certainly ACE always uses the best quality, and I'm
pretty sure that if you look at the guts of the profiles, you'll find
that the colorant values and TRCs are identical. I suspect PhaseOne
tried to be clever and failed...
My colour management studies have resulted in adopting the following colour
management policies:
Monitor and printer calibrated using Eye One Pro spectrophotometer.
Adobe Photoshop 7.01 CMM setting - Adobe (ACE} using Adobe RGB (1998) working
RGB colour space
Colorsync settings - Default profiles all set to Generic
ColorSyncs CMMs - Automatic
I understood that by selecting automatic in ColorSyncs CMMs choice it would
allow my Photoshop CMM choice of Adobe (ACE) to operate without ColorSyncs
Apple CMM interfering ?
If you choose ACE as the engine in Photoshop, that's what Photoshop
will use, no matter what settings you made in the ColorSync utility.
Profiles are allowed to specify a preferred CMM. Setting the Engine
to Automatic means that each profile will use its preferred CMM for
the conversion between it and the PCS. Since the only system-wide CMM
currently commonly available on OS X is the Apple CMM, that's
generally what system-level conversions will use. But most apps that
do color management ignore all the OS settings except for the display
profile. Photoshop (unless you choose "ColorSync Workflow" in Color
Settings) is no exception.
Bruce
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