Disable auto compression/optimization of background PDF

[Guus]

Many of my Writer (v6.4.6.2, but happened on older versions too) documents use a full page background PDF, that provides things like a letterhead.

This generally works well, but I’ve observed an annoying issue: whenever I copy a document to a new file (eg: next month’s version of the document), the quality of the background is noticeably reduced. It’s easily fixed by replacing the background PDF with the original file - but after a couple of years doing that every month, I’m growing tired of that.

What’s causing this loss of quality? Is some kind of optimization / compression taking place. Can that be turned off / prevented somehow?

[LeroyG]

Open the PDF background with Draw, export as .png (or .svg), and set the PNG as background.

or

Save an empty file as template (.ott), and open it every month.

[EarnestAl]

@LeroyG are you going to make that an answer?

As to the reason for loss of quality, probably the image in the pdf is jpg.

“JPEG is also not well suited to files that will undergo multiple edits, as some image quality is lost each time the image is recompressed” JPEG - Wikipedia.

PNG as suggested above is a lossless format for raster images so does not lose information every time ot is saved. SVG is a vector format and can be expanded hugely, or resaved without loss of quality

[LeroyG]

@EarnestAl,

probably the image in the pdf is jpg.

Could be a only text PDF, and the quality shown is not good.

[petermau]

I would use a template and document styles to provide the source for my repeating documents. You can then link the background image to the template. This means that you would reuse the original image for each document.

[LeroyG]

Open the PDF intended to be the background with Draw, export as .png (or .svg), and set the PNG as background.

Tested with LibreOffice 6.4.7.2 (x86); OS: Windows 6.1.

I think that the issue needs a bit more of study.

The ODT container has a copy of the PDF and a PNG of the background; but the PNG apparently has nothing to do with what we see (if you delete it, the file will not open; but you can replace it with another file as long as it has the same name…).

If you replace in the ODT container the PDF with another one with the same file name, you will get another medium quality background.

EDIT: Created a file with a full page PNG including the following 5 dots.

Saved, and reloaded it nearly ten times, and there was no bluring.

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