Bug 691443 - Difference with icc_work output
Summary: Difference with icc_work output
Status: RESOLVED FIXED
Alias: None
Product: Ghostscript
Classification: Unclassified
Component: Color (show other bugs)
Version: master
Hardware: PC All
: P4 normal
Assignee: Michael Vrhel
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2010-07-07 04:41 UTC by Marcos H. Woehrmann
Modified: 2010-07-11 15:28 UTC (History)
0 users

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screenshot.png (20.15 KB, image/png)
2010-07-07 04:41 UTC, Marcos H. Woehrmann
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Description Marcos H. Woehrmann 2010-07-07 04:41:51 UTC
Created attachment 6437 [details]
screenshot.png

There is a difference in output between Ghostscript 8.71 and head (r11492) that is likely related to the icc_work changes.  When converting the file altona_visual_1v2a_x3.pdf (which can be found in tests_private/compare_files) the number 28 element is rendered differently when converting to a CMYK format (e.g. tiff32nc); see the attached screenshot.png.  The output from Acrobat Pro 9.3.3 matches Ghostscript 8 .71

The command line I'm using for testing:

  bin/gs -sDEVICE=tiff32nc -o test.tif ./altona_visual_1v2a_x3.pdf

Note that when writing to a RGB format (e.g. tiff24nc) 8.71 and head match each other (and neither matches Acrobat).
Comment 1 Michael Vrhel 2010-07-07 13:52:11 UTC
There is something odd about this PDF file.  

It is a signed document that cannot be edited (at least in AR) and when I view the signed version with AR I get what GS provides as output.  i.e. the overlapping circles that do not interact like subtractive inks. Viewing the unsigned version with AR, the overlapping CM and Y do interact.  Also, there is a difference in the spot orange and black 2D overprint grid between the signed and unsigned version.  

Pushing out to PDF write (so that I could edit easily with AR) we get the overlapping circles that do not interact and no signature information.  Need to understand a bit more about why AR shows differences in signed and unsigned viewing and what exactly we should be showing.  This may also be a PDF interpreter issue. 

It looks like there is a CalRGB or CalGray color space that is also getting improperly converted into an ICC profile, which I will investigate.
Comment 2 Ken Sharp 2010-07-07 14:16:47 UTC
(In reply to comment #1)

> It is a signed document that cannot be edited (at least in AR) and when I view
> the signed version with AR I get what GS provides as output.

Which version of Acrobat ? Using Acrobat Pro 9 and Reader 9 I get a message that 'At least one signature has problems' but the circles display overprinted.

Acrobat Pro 7 and Acrobat Reader 5 display the circles without overprinting, however (but say noting about signatures).

I don't have an unsigned version of the file to check.

The inability to edit the document shouldn't relate to signatures, signed documents should be editable, its likely that the page contents are in a form or something similar, that often prevents editing in Acrobat.
Comment 3 Michael Vrhel 2010-07-11 15:28:21 UTC
Fixed with rev 11502.