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Scribus => PDF Generation => Topic started by: jozefk on January 17, 2019, 08:45:03 AM

Title: PDF 1.3 generation for Printing Press
Post by: jozefk on January 17, 2019, 08:45:03 AM
I have a question about PDF 1.3 generation for printing press. Everything is working fine except flattening the transparency. So my question is about the solution for flattening the transparency. How do you do that?
What I tried so far is to export the page to tiff then open it with GIMP and flatten it. After that I import it to Scribus again and it works that way, but I have a problem with colors then, because I have RGB profiles in GIMP and from Scribus I need to get CMYK PDF files for printing press. So the colors got messed up.
And the person who is making the plates is insisting on PDF version 1.3.

Is there some other way to flatten transparency without messing up the colors?

I use Scribus 1.5.4 on Windows and Linux.
Title: Re: PDF 1.3 generation for Printing Press
Post by: a.l.e on January 17, 2019, 11:48:00 AM
sadly, scribus cannot flatten transparencies.

there are a few "workarounds":

- avoiding transparencies.
- finding a print shop that correctly prints PDF 1.4 with transparencies.
- using ghostscript to create a CMYK PDF with flattened transparencies.
- using the full version of acrobat (or another pre-press tool).

Title: Re: PDF 1.3 generation for Printing Press
Post by: jozefk on January 17, 2019, 12:54:53 PM
Thank you for reply.
Can Ghostscript be used as a PDF printer or how would you create CMYK PDF version 1.3 and flatten the transparency with it?
Also, would that still keep the text in vector format?
Title: Re: PDF 1.3 generation for Printing Press
Post by: a.l.e on January 17, 2019, 02:32:19 PM
since the question pops up regularly, i've started taking notes about it.

here i've have put a few test files:

https://github.com/aoloe/scribus-manual-pdf-and-printing/tree/master/content/transparencies

with the command

gs -o test-transparencies-1.3.pdf \
   -sDEVICE=pdfwrite        \
   -dCompatibilityLevel=1.3 \
    test-transparencies-1.4.pdf

you can get a flattened pdf. but, as you were hinting in your reply, all text will be rasterized.
this might or not be a problem for you.

i will keeping on adding notes, so if anybody has further ideas, feel free to add them and/or making pull request with new test files or modifications to my test file.
Title: Re: PDF 1.3 generation for Printing Press
Post by: jozefk on January 17, 2019, 02:41:10 PM
I will have to test that. Even if it doesn't keep the text in vector format, I can still use it to flatten the transparency and then to import the PDF to Scribus again and add the text. Would that work?
Title: Re: PDF 1.3 generation for Printing Press
Post by: a.l.e on January 17, 2019, 03:01:03 PM
interesting approach...

yes, reimporting the pdf file into scribus should work.

if you use multiple layers you can have:

- a layer with items that have transparencies
- a layer with the flattened items
- a layer with the rest of the content

in that way you can turn layers on and off to first create the pdf to be flattened or the final pdfs.
Title: Re: PDF 1.3 generation for Printing Press
Post by: jozefk on January 17, 2019, 03:19:35 PM
Perfect. I will try that and see how it goes. Thank you!
Title: Re: PDF 1.3 generation for Printing Press
Post by: jozefk on January 24, 2019, 11:59:34 AM
This didn't work good enough on Windows. Haven't tested it yet on Linux but I guess it would be the same. Colors were messed up if I export the layer for flattening to PDF 1.4 and then convert it to PDF 1.3 with Ghostscript and import it back to Scribus. It doesn't work that way.
What works though is to export the whole thing to PDF 1.4 then to convert it to PDF 1.3 with GhostScript. But in that case some lines of text on path got messed up. Not in PDF 1.4 which I made with Scribus but in PDF 1.3 made by Ghostscript.

Another way of doing it is to export the artwork to TIFF, from Scribus then to print that TIFF to PDF 1.4 with PDFcreator (unfortunately it works only on Windows it seems) then with Ghostscript to convert that PDF 1.4 to PDF 1.3. That all works good, but there is one problem: text is not 100% K. And it's not overprint or anything like that. The file is just flat, raster image.

When I try to import the TIFF (before I print it to PDF) back to Scribus, it doesn't work. No idea why. Same thing with PDF which got from the TIFF...

Lot's or issues, unfortunately.

I don't know why the RIP for plates insist on PDF1.3 but that's how it is.

Otherwise Scribus got some great features which I didn't even see in paid software! Yeah the way things work in Scribus is a little weird and uncommon let's say, but it works. Oh, the undo is not working on Windows and that's crazy :))

Maybe I have to look into option of getting Acrobat Pro and to try to print the file from Scribus to PDF with Adobe printer and see what happens. That solution would be for Windows only I guess.