[scribus] PDFX3, CMYK and opacity

[Peter Linnell]

On 02/14/2012 10:52 AM, JLuc wrote:
> Le 14/02/2012 18:10, Gregory Pittman a écrit :
>> On 02/14/2012 11:41 AM, JLuc wrote:
>>> Hello,
>>>
>>> I have been struggling for the last days with generating the right PDF
>>> for the big printer company that shall print it.
>>>
>>> I have accepted the fogra27 color profiles in the document settings.
>>> Fogra27 is also the color profile requested by the printer.
>>>
>>> The printer requests PDF X3.
>>> But when i set PDF output to be PDFX3, the "color" pane in "export to
>>> PDF" dialog
>>> becomes grayed out and inactive.
>>> As a consequence, I cannot choose anymore "printer" as a direction
>>> ("printer" means "CMYK").
>>>
>>> As a result, printer says "some pictures are CMYK and some are RGB in
>>> your file".
>>> That would probably lead to a color disaster.
>>>
>>> X3 is a subset of PDF 1.3 and "color" pane is well disabled with PDF1.3.
>>> So why is the "color" tab of "export to PDF" disabled
>>> when "PDFX3" is choosen ?
>
> Sorry i made a typing error. You should read :
> "color" pane is well active with PDF1.3
> (but not with PDFX3).
> I answer at the bottom of the mail.
>
>>> And how to get a correct PDF ?
>>> This is the most crucial question i have now.
>>>
>>> Another problem / question i have is about opacity.
>>> The first time i sent a PDF of that file it was PDF1.4
>>> and there was a 70% opacity frame in it.
>>> I choosed 1.4 since opacity or transparency is not available before 1.4,
>>> but the printers cromalin (preprint trial) printed the 70% layer
>>> with a 0% opacity that is : it wasnt printed at all !
>>> So i decided to change the image so as to be able to include it with
>>> 100% opacity
>>> but that would not have been possible if i had lots of pictures with
>>> opacity.
>>> And what about backgrounds and texts ?
>>>
>>> When i ask a PDFX3, that is a subset of PDF1.3, how do Scribus treat
>>> opacity ?
>>> Does Scribus compute the equivalent colors points (rasterizing) at a
>>> 100% opacity ?
>>> Or it includes the opacity instruction as it is, without caring that
>>> PDFX3
>>> cannot handle this ?
>>>
>>
>> Is this a problem with the PDFs or a problem with your printer?
>>
>> When a PDF 1.4 doesn't show transparency, one has to wonder if the
>> printer's software is handling it properly. (I am
>> presuming you looked at your 1.4 in Adobe Reader to make sure the
>> transparency was indeed there.) And if that's the
>> case, then they may not be handling PDF/X-3 properly either.
>>
>> We have seen before situations where printers seem inflexible, perhaps
>> related to licensing costs, and blame their
>> customers for their own limitations.
>
> Sure. Sticking to X3 seems not very modern... and i am open to all
> possible explanations.
> But i have not had such problems when working with other DTP software.
> Enlarging my understanding of color profiles, transparencies and PDF
> versions
> would help discussing and maybe negociating with the printer.
>
> But most important : i will not change printer, so i need to find my way
> with it,
> and understanding how scribus deals with these issues would help me
> to choose the right parameters in this specific case.
>
> For example : why is "color" pane not enabled when PDFX3 is choosen ?
>
> JLuc
>

A couple of pointers:

PDF-X does not handle transparency at all. It is a limitation of the spec.

PDF-X3 allows mixing of CMYK and RGB images. In fact it can be all CMYK 
or all RGB, as well.

Color is disabled in the PDF tab as certain settings cannot be disabled 
to ensure the pdf is  compliant to the spec.

Myself, I would be sending pdf 1.4 and if the transparency results are 
not correct, then it is an issue with the printer's workflow. Are they 
importing the PDF into another application beyond Acrobat Pro ?

You are welcome to send me off list a link to the file, where I can run 
some special pre-preflight tools to verify the pdf.

Hope that helps,
Peter