Jonathan Kamens 86 47Sep 9, 2025
There is, finally, a decent way to edit / redact a #PDF for free on the desktop.
I don't know when exactly #LibreOffice Draw advanced to this level, but in the current version you can open a PDF, edit the text and graphics in it, and save it as a PDF.
Two caveats:
1) It sometimes doesn't read image cropping info from the PDF, so you may need to recrop images.
2) Make sure you have all the fonts in the PDF installed on your system before editing it, or Draw will substitute different fonts.
#FOSS
Show threadJonathan Kamens 86 47Sep 9, 2025
To find out what fonts are used by a #PDF, you can use, e.g., the "pdffonts" command that comes with #Poppler (in #Debian and Debian-based systems it's in the "poppler-utils" package).
#FOSS
Show threadJonathan Kamens 86 47
Editing or redacting a #PDF using #LibreOffice Draw is far superior to the commonly used method of converting the PDF's pages into images and editing the images, because the latter results in a PDF that is many times larger and doesn't render as well. Also, text copy and paste is lost, which you can recover from to some extent with a tool like #OCRmyPDF, but you'll never get the text quality back to as high as it was before you converted the PDF to images.
#FOSS
Sep 9, 2025 at 8:31amWeb
Show threadלָקס (לא לותור) لاكس🏴Sep 9, 2025
@jik fwiw you can reconvert an image into pdf to select text, because browsers use character autodetection algorithms
Show threadDr Neenah Estrella-LunaSep 9, 2025

@jik Not free but I use PDF Xchange. Got a perpetual license for less than $100. Not sure if it operates in Linux though.

I don't mind paying for software that works well and this one works just as well as Adobe and even better that it's not putting my files at risk of being sucked into some AI nonsense.

Show threadTristan MillerSep 10, 2025
@jik The nice thing about redacting a PDF by converting it to images is that you can be reasonably sure you've eliminated any hidden text and metadata. A lot of sensitive information might be accidentally or deliberately lurking unseen in a PDF (white-on-white text, microscopically sized text, text off the canvas or clipping path, text in unused streams, etc.).
Show threadTristan MillerSep 10, 2025
@jik And if the PDF is just black-and-white text, converting it to a bitmap and back to a PDF again won't balloon its size much, provided you reduce the bit depth to 1 and use CCITT G4 compression. You can run the result through OCR to partially fix the accessibility issues.
Show threadJonathan Kamens 86 47Sep 10, 2025
@Logological For the most part there's no such thing as "black and white text" nowadays. Pretty much every font and font renderer font renderer uses grey-scale. Converting a text document to one-bit black-and-white usually yields pretty poor results.
For example, on the left is a screenshot of your post. On the right is that exact image converted to 2 colors.
Show threadTristan MillerSep 18, 2025
The quality you see is largely a function of the original resolution of the text, though. A PDF containing only text in outline fonts, rendered at >=300 dpi and then converted to 1-bit colour, will look pretty close to the original in a modern viewer (at normal zoom levels, anyway). Yes, you won't get FreeType-quality font rasterization, but most PDF viewers do a pretty good job of downsampling bitmaps, with grey pixels to soften jagged edges.
Show threadJonathan Kamens 86 47Sep 10, 2025
@Logological I agree with you that in high-security or highly sensitive situations it is safer to use the method of converting the PDF into images rather than using something like LibreOffice Draw to edit it.
Having said that, I think using Draw is adequate for most purposes.