Re: So what does Preview.app *really* do when softproofing?
Re: So what does Preview.app *really* do when softproofing?
- Subject: Re: So what does Preview.app *really* do when softproofing?
- From: Uli Zappe <email@hidden>
- Date: Tue, 22 Apr 2008 09:32:56 +0200
To follow up on my own question:
does anyone happen to know what *exactly* Preview.app does when it
offers a softproof (the tiny "Softproof" checkbox in the lower left
of the window that gets opened when you click "Open in Preview" in
the Print panel)?
[...]
I've tried various other ways of emulating this softproofing process
(using the command line utility sips, writing my own C program with
ColorSync Manager functions, even calculating the matches by hand
with ColorSync Utility's Calculator), and again, while every
approach comes very close to Preview, not a single one matches its
results exactly.
So what precisely are the steps that Preview performs to offer a
softproof?
Turns out that as far as AppleScript is concerned, I was overlooking
the correct combination among the countless possible ones.
proof <imageFile> to destination <printerProfile> matching with
perceptual intent onto proof <displayProfile> proofing with perceptual
intent using quality best
will do *exactly* what Preview does. (You can most probably omit the
"matching with" and "proofing with" options; I just included them for
clarification.)
Strangely enough, I was still not able to reproduce this result in C.
The corresponding ColorSync Manager settings for NCMConcatProfileSpec
{0, cmBestMode << 16, cmQualityMask, 3,
{
{cmPerceptual, kDeviceToPCS, <sourceProfile>},
{cmPerceptual, kPCSToPCS, <printerProfile>},
{cmPerceptual, kPCSToDevice, <displayProfile>},
}
};
do *not* lead to the expected result, but a slightly different one (dE
mean/max 0.83/2.41).
Ah, the joys of consistent color management ... 8-)
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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