I assume many of you host a DMS such as Paperless and use it to organise the dead trees you still receive in the snail mail for some reason in the year of the lord 2023.

How do you encode your scans? JPEG is pretty meh for text even at better quantisation levels (“dirty” artefacts everywhere) and PNGs are quite large. More modern formats don’t go into a PDF, which means multiple pages aren’t possible (at least not in Paperless).

Discussion on GH: https://github.com/paperless-ngx/paperless-ngx/discussions/3756

  • AtemuOPEnglish
    1·
    1 year ago

    I use SANE, then do lossy compression too.

    Well, what kind of lossy compression? JPEG?

    IME, JPEG looks quite terrible for text documents -even at q=95.

      • AtemuOP
        1·
        1 year ago

        Hmm, I’m using grayscale PNGs as my baseline here. A 150dpi scan is about 1.3MiB.

        A (for the purpose of text documents) similar quality WEBP is about 1/4 of that.

        • kyle@infosec.pub
          1·
          1 year ago

          You could also try adjusting the contrast a bit. I use an app called Genius Scan, which increases the contrast of the scanned image to reduce the number of bits needed per pixel. This reduces the size of the file quite a bit, although it obviously isn’t a true representation of the scanned document. The TextCleaner imagemagick plugin looks like it’s doing something similar.

          • AtemuOP
            1·
            1 year ago

            Yes, as I said.

            As also mentioned in the post, I need a solution for multiple pages and an image (no matter what format) only represents a single page and WEBPs don’t go into PDFs.

              • AtemuOP
                1·
                1 year ago

                That’s nice and all but does not answer how you’d create the PDF. Whether that happens outside paperless inside paperless does not make a difference. In the end, I need to create a PDF/A out of some images and the question on how to encode these images still remains.

                • dpflug@hachyderm.io
                  1·
                  1 year ago

                  @Atemu
                  A couple options to create PDFs were mentioned in the linked issue.

                  Image encoding before PDF creation is immaterial as long as your PDF creator supports them. I use PNG because they’re well supported and lossless.

                  After conversation to PDF, we’re stuck with what PDF supports: various PNM-ish formats, jbig2, jpg, and jpx (aka jpg2000). Everything else gets converted. Nothing can change that. It’s in the PDF specification. jpx is the best lossy option for text, but support is a mess. 1/2

                  • dpflug@hachyderm.io
                    1·
                    1 year ago

                    @Atemu
                    In theory, you can use image2pdf or ghostscript to pack jpx files into a pdf. Try it, I guess?

                    There are a bunch of other tools that can scan directly to PDF, multi-page TIFF, or assemble multiple images into a multi-page pdf. Which to choose comes down to what sort of workflow you want.

                    But if you’re going for the best quality at small size, you’ll have to fight with jpxs. 2/2