[Openicc] Ghostscript PDF/X-3

[Michael Vrhel]

Kai-Uwe,

If a device ICC profile is explicitly given using the command 
ption  -sOutputICCProfile="my_device_profile.icc" then the assumption is 
that this is truly the ICC profile that describes the device I am printing 
to.   If in addition, I include the option -dUsePDFX3Profile, then the 
OutputIntent ICC profile will be used as a proofing profile, so that when I 
print (or display) to my actual device I should see what was intended to be 
see as if it had been displayed with the device described by the 
OutputIntent.

This proofing will also occur if the process color model does not match the 
process color model of the OutputIntent.   For example, if I am rendering 
out to an RGB device and I specify -dUsePDFX3Profile and my OutputIntent is 
a CMYK ICC profile.   Again, I would like to see on the screen an 
approximation of how it would appear if printed on the CMYK device.

If I do not specify an ICC profile for my device with  something 
like -sOutputICCProfile="my_device_profile.icc" and the process color model 
for my device matches the color space of the OutputIntent and I 
include -dUsePDFX3Profile on the command line, then the output will be 
rendered into the color space defined by the OutputIntent ICC profile, 
assuming that the OutputIntent included an ICC profile and was not simply a 
registry and a standard profile name.

Does this all make sense?

I still have a few issues remaining that appear to be with the rendering 
intent in the proofing case that I am tracking down.   These show up in the 
Ghent testing files.    I will have these addressed before the release of 
9.06 in August.

Kind Regards,

Michael




-----Original Message----- 
From: Kai-Uwe Behrmann
Sent: Monday, March 19, 2012 7:50 AM
To: OpenICC Liste
Subject: [Openicc] Ghostscript PDF/X-3

The new -dUsePDFX3Profile Ghostscript option [1] implies to pick a
OutputIntent profile as destination profile only in case that option is
specified. However for the last two sentences of the -dUsePDFX3Profile
description in Use.html, I was not quite sure to had translated properly
to my thinking language ;-)

Regardless the rules for Device colour spaces, I would like to understand
if the -dUsePDFX3Profile option alone will already override any fallback
-sOutputICCProfile option? So Ghostscript will take over the PDF expert
responsibility to meet the PDF/X-3 standard, which would be greatly
appreciated.

Between the behaviour, to use the OutputIntent as a proofing profile in
case it's colour space does not match the intented output device colour
space, is a interesting feature for on screen displaying.

kind regards
Kai-Uwe

[1] 
http://git.ghostscript.com/?p=ghostpdl.git;a=blob_plain;f=gs/doc/Use.htm;h=3bd2519161e8271aaa630edfd19b1e033c350c48;hb=82d1d263a13ccfe64e78cd0e6f1cf1a275adcb9c
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