Re: [ECI-EN] RGB and CMYK files in a PDF/X-3:2002 file - ECI-EN

17 Mar 2008

      Hello Peter, hello list
May be, we both are using different definitions about "device 
independent workflows".
For me a device independent workflows based on PDF/X must include:

- predictable and pleasant colormanagement of images and vector graphics
- easy integration  printing processes with very different colors for 
the primaries (e.g. offset according ISO 12647-2 and gravure printing 
according PSR ECI
- Independence of profiling vendors
- defined procedures for the quality control of all color 
transformations in the workflow

Neither ECI, ICC, ISO TC 130 or GWG have ever published a guideline and 
tested in practice how this could be realized with PDF/3 or PDF/X-4 
containing ICCbased objects.

You may be able to use PDF/X-3 or PDF/X-4 in repro inhouse workflows as 
an internal color master, if you have the control over the complete 
creation of the layout documents, the master PDF/X files and the 
profiles for all printing conditions in the workflow. File format 
delivered to the printer should then always be PDF/X-1a or CMYKonly 
PDF/X-4 (plus Spotcolor if necessary).

If we are talking about controlled color transformations  of incoming 
PDF/X files at the printer. PDF/X-1a or CMYKonly PDF/X-4 in combination 
with devicelink based color servers are today the only available 
technology which is able to full fill all the points I described at the 
beginning of the mail.

Regards
Jan-Peter

Peter Kleinheider wrote:
...
  Jan-Peter,

 having set up quite some device independent  workflow's in the past, I 
 do not agree to your statement.
 If you can make sure that BPC is used at the end doing the final color 
 conversion, than this is a pragmatic workaround.

 However I agree, that this can be a pitfall if such a PDF is sent to 
 an "unknown" site which has BPC turned of (or BPC even not available).

 Nevertheless, it works.

  For the future, I hope that ISO TC 130 and/or GWG
specify a "CMYKonly
 PDF/X-4" version (or GWG recommendation) like PDF/X-1a plus 
 transparencies.
 A "CMYKonly PDF/X-4" recommendation by GWG would have the advantage,
 that it could be specified on top of the ISO standard PDF/X-4 without
 the need to change the ISO-standard itself. This could be realized in
 months instead of years for the ISO procedures... 
 Being partly responsible for that I can tell you that we were in fact 
 discussing such a new spec at the last meeting. However, we also have 
 the demand to allow icc based elements (still disallowing 
 ICCbasedCMYK) in a PDF. For that PDF/X-4 has already most of the 
 provisions we need.

 It would be great the hear the opinion of other users on this idea?

 Best Regards,

 Peter Kleinheider
 Co-Chair Colormanagement Subcommittee of GWG

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