Bug 128978 - Exported PDF files are too big with setting Archive PDF/A-1b
Summary: Exported PDF files are too big with setting Archive PDF/A-1b
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: Printing and PDF export (show other bugs)
(earliest affected) release
Hardware: All All
: medium normal
Assignee: Not Assigned
Depends on:
Blocks: PDF-Export
  Show dependency treegraph
Reported: 2019-11-23 14:32 UTC by Paolo
Modified: 2020-07-15 09:47 UTC (History)
2 users (show)

See Also:
Crash report or crash signature:

Document to export in PDF and export results (3.03 MB, application/zip)
2020-04-25 14:08 UTC, Paolo
Paolo PDF export settings (260.23 KB, application/x-xz)
2020-07-11 18:04 UTC, Paolo

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Description Paolo 2019-11-23 14:32:11 UTC
PDF export function has begun to export too big files: a more then 2 MB file out of a 97 kB writer file.
In previous version ( this size was more little, but, anyway, bigger than with

Same writer file exported to PDF with was less then 250 kB with
Comment 1 Roman Kuznetsov 2019-11-23 18:08:56 UTC
Paolo, please attach example ODT file here
Comment 2 Paolo 2020-04-25 14:08:57 UTC
Created attachment 159921 [details]
Document to export in PDF and export results

Here attached the Word 97 document (it's my CV) and the result of its PDF export made with new LibreOffice version, and the same export made with Microsoft Word.
And there is the same file, saved in odt format and exported again in PDF with Write
As you can see, using MS Office 2018 PDF size is 221 kB, using LO is 1.7 MB, almost 9 times bigger.
Comment 3 Paolo 2020-04-25 14:16:38 UTC
Sorry to reply to you after 4 months, but I had very bad times.
Just one note: a LO message says "Trasparencies removed" during export process both with .doc file and .odt file.

Again, with LO (and previous) the exported PDF dimension was almost the same that the PDF generated by MSWord.
Comment 4 Buovjaga 2020-07-11 14:16:20 UTC
Tested by exporting cv_ing_paolo_rossi_2019.doc to PDF. Resulting file size is 57,5 - 66,7 kB (tested on Win and Linux).

Paolo: please tell us your PDF export settings. Also test with a newer version.

Change back to UNCONFIRMED, if the problem persists. Change to RESOLVED WORKSFORME, if the problem went away.

Arch Linux 64-bit
Build ID: 6.4.5-2
CPU threads: 8; OS: Linux 5.7; UI render: default; VCL: kf5; 
Locale: fi-FI (fi_FI.UTF-8); UI-Language: en-US
Calc: threaded

Arch Linux 64-bit
Build ID: 57fedb272cfcad3436142dbe9eac2870e3c3e3d2
CPU threads: 8; OS: Linux 5.7; UI render: default; VCL: kf5
Locale: fi-FI (fi_FI.UTF-8); UI: en-US
Calc: threaded
Built on 9 July 2020

Version: (x64)
Build ID: 9af38b4504ccda57a0c32eb8bdd03e5a8ca29ddc
CPU threads: 4; OS: Windows 10.0 Build 18362; UI render: Skia/Raster; VCL: win
Locale: fi-FI (fi_FI); UI: en-US
Calc: threaded
Comment 5 Paolo 2020-07-11 18:03:20 UTC
I'm asking you to wait 'till my system will update from LibreOffice to

At the moment I can only upload PDF export settings I'm using (screenshots are in italian, since it's my default language).
Comment 6 Paolo 2020-07-11 18:04:23 UTC
Created attachment 162903 [details]
Paolo PDF export settings
Comment 7 Buovjaga 2020-07-11 19:10:17 UTC
Thanks for the settings. The setting that causes this is Archive PDF/A-1b. If you pick PDF/A-3b, the size will only be 230 kB. Perhaps this is not a bug, but somehow related to the archival specifications.

The options regarding the archive setting had some changes in the 6.3 line, I checked using the Linux 6.3 bibisect repository. It seems PDF/A-1b was not available previously, but only PDFA-1a.

Comment 8 Paolo 2020-07-12 09:42:52 UTC
I can confirm that using PDF/A 2b the size is the same as before (when I was using PDF/A 1-a). So I too believe that 200 Kb is the size determined by the PDF/A specification.
Thank you for your work on this subject
Comment 9 Buovjaga 2020-07-15 09:47:30 UTC
Ok, got a reply on the dev list: "the oldest version of PDF/A does not support transparency and the emulation of that tends to blows up file size dramatically."