Exported pdf files are significantly bigger than before

[BlueRay]

A few weeks ago I updated all the programs on my manjaro Linux laptop, including gimp. Today I used this updated gimp and tried to make some small changes to a PDF file and then to export it again as PDF. 

On this latest version of gimp (2.10.36) such an exported PDF file turned out to have 3.7 Mb. 

On the previous version of gimp (2.10. 28) the same pdf file with the same adjustments and settings when exported as pdf has only about 475 Kb.

Everyone can probably replicate the same thing if you open a smaller PDF file in gimp 2.10.36 (let's say around 400 Kb) and even without any changes export that same file as PDF. The exported file will be significantly larger than the original. However I presume that this might happen only with PDF files that contain scanned images. I haven't experimented with plain text PDF files.

I wonder why this change was introduced into the latest gimp version which is available for the installation on manjaro (2.10.36)? It doesn't make sense to have a significantly larger file which is not better in any way than the smaller one from previous versions of gimp.

[PixLab]

There are no GIMP developer in here, go to the top GIMP menu Help > Bug Reports and Feature Requests, a window will open in your browser, explain the problem on that website, developers are over-there

[rich2005]

@ BlueRay

I can think of one possibility, The default resolution for opening a PDF has changed from 100 ppi to 300 ppi.  This is to prevent users opening a PDF as a low quality image.

The reported size in real world units inches / centimetres / remains as originally specified.

This 8" x 10" from an old Gimp has a saved file size of 206 KB If the ppi is not changed to to suit, it opens at 300 ppi Edited and re-exported it is now 2.2 MB on disk. Some 9 times larger  (300% horizontal x 300% vertical).

   

[BlueRay]

(03-06-2024, 04:42 PM)rich2005 Wrote: @ BlueRay

I can think of one possibility, The default resolution for opening a PDF has changed from 100 ppi to 300 ppi.  This is to prevent users opening a PDF as a low quality image.

The reported size in real world units inches / centimetres / remains as originally specified.

This 8" x 10" from an old Gimp has a saved file size of 206 KB If the ppi is not changed to to suit, it opens at 300 ppi Edited and re-exported it is now 2.2 MB on disk. Some 9 times larger  (300% horizontal x 300% vertical).

Yes, that is the most likely reason for significantly bigger exported pdf files. If I change the resolution from 300.000 to 100.100 while opening a pdf file, the exported pdf file will be around 400 Kb, like with the previous versions of Gimp. Thanks for explaining this.

Is there a way to change this default setting for Resolution in gimp settings so that there is no need to specify a lower resolution every time one opens a pdf file?

[rich2005]

(03-08-2024, 10:10 AM)BlueRay Wrote: ...snip...
Is there a way to change this default setting for Resolution in gimp settings so that there is no need to specify a lower resolution every time one opens a pdf file?

No, that is the reverse of the previous situation where Gimp users complained about having to up the value from 100 to 300.

PDF is just a wrapper, and for an image Gimp has low compression. If you want a smaller PDF, export to a more compressed file, say a jpeg.
ImageMagick makes a smaller PDF from the jpeg. However a PDF is supposed to be a 'finished' format, not meant to be edited (although it happens)