GIMP PDFs have transparency

[waltonm]

Thank you all.  

From the answers above, I assume:

• Transparency is an artifact of how GIMP exports to PDF.
  
• There are no settings in the process that can prevent it.
  
• There is nothing that can be done to the source file--flattening, merging visible, export to JPG--that can prevent it.
  

Several people have said that GIMP won't work for me.  This has nothing to do with me.  I am trying to provide advice to the many people who use GIMP to help publish their books on KDP.

Thanks again,

Walton

[rich2005]

(03-29-2025, 03:09 PM)waltonm Wrote: I am trying to provide advice to the many people who use GIMP to help publish their books on KDP.

Tell them some post-processing is required.  We have gone over this before ....

Gimp 3.0 (or as far as I can tell Gimp 2.8 is the same) is not going to give you a PDF without some trace of transparency. I suppose that softmask element. Used for effects such as a gradual transition between an object and its background. 

If you are opening an image in Gimp it does become an internal bitmap format and that is incorporated into an exported PDF. That is one reason why Gimp PDF's are generally on the large size.

Two cases: sorry for the linux syntax.

From Gimp - no alpha - exported to PDF with all options off. Using that linux command.
grep -aE -e '/[Cc][Aa] +0?\.[0-9]' -e '/SMask' -e '/S /Transparency' gimp.pdf
      /gs0 << /BM /Normal /SMask  /None /CA 1.0 /ca 1.0 ➤

From ImageMagick - the image as a jpeg - and an added bonus of a smaller PDF file size.   
grep -aE -e '/[Cc][Aa] +0?\.[0-9]' -e '/SMask' -e '/S /Transparency' im.pdf
     give nothing - no elements reported.
     
So, not possible to use Gimp for your specification, very easy with a bit of post processing and ImageMagick does keep the document size which you said you lost using a PDF printer utility.

[waltonm]

Again, thank you.

I am keeping the "How to Create Your Cover" tutorial using GIMP. It's a good graphics program. Looking at the PDF options, and given that 99.9% of the people I work with are doing books, a workable solution is to open the cover art in Scribus.

Walton

[rich2005]

(03-29-2025, 05:28 PM)waltonm Wrote: Again, thank you.

I am keeping the "How to Create Your Cover" tutorial using GIMP.  It's a good graphics program.  Looking at the PDF options, and given that 99.9% of the people I work with are doing books, a workable solution is to open the cover art in Scribus.

Walton

Scribus is a very good option. It is after all a dedicated DTP application.  There is a bit of a learning curve but plenty of advice around.