Export or print to pdf from writer?

[snowforest]

Which one is better? Export as pdf or print to pdf, from writer?
And when I do both I see that lets say for a 43 page document, the exported version is 1.13 MB while the printed versio is 4.82 MB. 4 times more… Where does the difference come from? Does this mean printed version is higher quality in some way? Or it means it is less efficient and both versions are exactly same quality?

Also how do you view the page size of a pdf document when you open it with libre draw? (again, not make page size, but view the page size of a pdf document that you open with libre draw)

[robleyd]

Did you try Page | Properties to see what the page properties are?

[snowforest]

Ok now I see it thanks. And any idea about my first question?

[robleyd]

If I knew the answer, I would have responded.

[EarnestAl]

Open the pdf with a pdf reader, not Draw (Draw is not a pdf reader). If you open it with Adobe Reader, then clicking File > Properties will give you the page size on one of the tabs.

[LeroyG]

Export as PDF gives you a few options on images that could explain the file size difference:

[EarnestAl]

A quick test of a 25 page odt of just unformatted text without images, dt AutoText:

• .odt = 28kb
• Export as PDF = 70kb
• Print to DoPDF = 761kb
• Print to Microsoft PDF = 109kb
• Print to Bullzip PDF = 82kb
• Save As .docx = 6kb
• Word Save as pdf (Standard) = 189kb

There are huge differences in size for almost identical output, Export to from LO and DoPdf had blacker text, all embedded font Liberation Serif except that Microsoft Save as PDF embedded a different name (CIDFont+F1), so I am picking efficiency of compression

[LeroyG]

Tested with a screenshot (1440*900) of this page pasted on an A4 Writer document:

• LO lossless compression at 300 dpi = 112 kB
• LO JPEG compression 90% at 300 dpi = 112 kB (at 400% zoom I can’t see any obvious difference with lossless compression)
• MS Print to PDF = 134 kB (with a sandy (?) view)

Tested with an astronomy picture (4000*2788) pasted on an A4 Writer document:

• LO lossless compression at 300 dpi = 5889 kB
• LO JPEG compression 90% at 300 dpi = 776 kB (at 400% zoom I can’t see any obvious difference with lossless compression)
• MS Print to PDF = 1034 kB (with a better quality)

Opening this last image PDFs with Draw, after copying and pasting in an image editor it size gives:

• LO lossless = 2009*1400
• LO JPEG = 2009*1400
• MS Print to PDF = 4000*2788

[LeroyG]

So, the questions are:

Do you really need that big images be kept this big to use them latter?

Would you use the PDF in a screen (96 dpi is enough in most screens) or to print (300 dpi is enough)?

Your print-to-PDF program allow you to set dpi, compression, etc.?

[EarnestAl]

This thread was interrupted by the transition to Discourse but I feel it needs an answer.
@LeroyG showed that Export as PDF in LO led to better image quality at smaller file size
My experiments showed that the smallest file size for text only was obtained by Export as PDF without any significant differences in output (except Microsoft Word Save As pdf which changed the font name to an unknown one). This would be expected if export worked in a similar manner to zip compression where similar patterns are replaced by a defined token.
Additional benefits of Export as PDF in LO are retention of bookmarks, TOC, footnotes and endnotes, indexes, and hyperlinks as clickable links, as well as Hybrid pdf possibility and all the security options.

Export as PDF in LibreOffice creates a smaller but better pdf for most common uses.