Re: Distiller 5 CSA to ICC matrix
Re: Distiller 5 CSA to ICC matrix
- Subject: Re: Distiller 5 CSA to ICC matrix
- From: Peter MacLeod <email@hidden>
- Date: Tue, 8 May 2001 17:06:24 -0700
Olaf Druemmer wrote:
The only thing that is annoying is that we have to figure this out by
experimentation (in such an area I consider experimentation and
professionalism mutually exclusive...). I got some confirmation from
Adobe about this behavior but would rather prefer to have a precise
description of what is happening when.
There is no formal spec posted, but yes, it would be useful to know
what the matching criteria are, so here is an informal description.
Please note that this has not been reviewed extensively, standard
disclaimers apply...
I'm sending this to PDF-Prepress-L as well. "PSLR3" below
refers to "PostScript Language Reference, Third Edition" which was
published by Addison-Wesley in 1999.
Applications can emit the following keys in CSAs and CRDs created
from ICC Profiles:
/CreationDate
As defined in PSLR3, page 468, for CRDs
/RenderingIntent
As defined in PSLR3, page 468, for CRDs
/Description
7-bit ASCII description string from the ICC profile 'desc' tag
/ColorSpace
Color Model of the profile data from the ICC profile header
/Copyright
7-bit ASCII copyright string from the ICC profile 'cprt' tag
When Distiller 5 encounters a CSA in the PostScript stream,
it attempts to find a matching ICC profile using the following matching
algorithm:
If the Description, ColorSpace, and Copyright strings of a profile
all match the keys in a CSA that is being distilled, then that
profile is a "candidate" for matching. Using a proprietary algorithm
(i.e. one which I do not have clearance to describe at this time)
the actual data in the CSA is compared to the relevant table in the
ICC profile. There is one additional heuristic: DEFG CSAs are
always accepted if they pass the Description, ColorSpace, and Copyright
string test, due to a problem in some earlier DEFG conversion code
which caused the matching algorithm to fail.
Thanks,
Peter MacLeod
Adobe Systems, Inc.