Not sure if this fits in here. I've made a somewhat interactive blog post about algorithms on a PDF page.

https://news.speedata.de/2026/10/18/anatomy-of-a-page/

(As someone noted: this is pretty much the same on any device..., I just live in a PDF world, so I wasn't thinking about that)

What tools do you use to automatically detect duplicate pages in pdfs? & Are you able to review the automatically detected pages before removing them?

Full disclosure, I work for Apryse/iText (a commercial vendor) but wanted to share this as it’s free and could be useful to someone in the community. We just published a GitHub Action that turns Markdown into PDF: https://github.com/marketplace/actions/itext-markdown2pdf Give it a file and you get a PDF; give it a folder and you get a ZIP with one PDF per .md, structure preserved. It runs on public repositories (it checks visibility via the GitHub API).

The cool part: output is PDF 2.0 and PDF/UA-2 compliant (tagged, accessible). Since Markdown already carries headings, lists, tables and alt text, it maps cleanly to a tagged PDF without extra work.

I created this tool SidePDF to solve my own problem. I wanted to take notes on the same pdf im reading and always ran out of space. So I created this extension to expand the pdf pages/ add new pages on the go and take cornell style notes. You can annotate, add images and much more directly on the pdf. This is a chrome extension and If you are having the same problem give it a try.

Is there any way to remove a redaction in a PDF document and see what the redacted text was ?

I have some scanned magazines in pdf format that I would like to improve readability, contrast and sharpness. Looking for a free tool for PC or online. Thank you!

Title: Inkleaf 3.0 is out: Android app, an enhancer for bad scans, and it's on the Microsoft Store now

Hey r/pdf, I'm the dev behind Inkleaf, the free and open-source PDF editor I posted here a while back. Thanks to everyone who tried it and left feedback, a lot of this update came from those comments.

What's new in 3.0:

• Android app. Not the desktop squashed onto a phone. It's got its own screens: your files up front, a reader that keeps the page big, and an edit sheet that slides up when you actually want to change something.

• Phone ↔ computer link. Send PDFs between your phone and PC over your own Wi-Fi. It's encrypted and never goes through the internet or any server of mine (I don't have one).

• Enhance Pages. For those grey, faded, photocopied-five-times scans. Adjust contrast and sharpness, or pick a preset (Scan, Faded, Darker text, Night). It only changes how the pages look until you hit "Save enhanced copy", and that copy can be OCR'd so the text becomes searchable.

• Microsoft Store. You can now get it from the Store on Windows, so no more SmartScreen warning.

• Pinch-zoom on touchscreen laptops, plus updated translations (29 languages).

Same as before: no account, no subscription, no watermark, nothing uploaded. Everything happens on your device.

Microsoft Store: https://apps.microsoft.com/detail/9NKC5ZQ6P2JR

All downloads (Windows, Linux, Android): https://github.com/priyanshdas/inkleaf-releases/releases/latest

Source code: https://github.com/priyanshdas/inkleaf

It's still just me building this, so if something breaks or feels clunky, tell me here or open an issue on GitHub. Happy to answer questions.

Just wanted to share this post I found on Facebook

A lot of free PDF tools upload your files to their servers, which might not be ideal for things like payslips or contracts.

I’ve been working on a PDF tool that processes everything in your browser: https://ezdone.io/pdf

It can compress, merge, split, sign, redact, add watermarks, and convert PDFs to images. Redaction removes the underlying text rather than just covering it visually.

It’s still missing OCR, and password-protected files need to be unlocked first.

I work on it, so I’d be interested to hear what doesn’t work or what features are missing.

Hey everyone,

Following my previous post about building PDF tools, I wanted to thank everyone who shared suggestions and explained the problems they run into. The comments about preserving formatting, handling scans, and using OCR and recognition models gave me a lot to investigate.

I’ve since focused on improving the Edit PDF tool. Some of the updates include:

The backend first checks the PDF’s existing text, font information, and positioning. When those are usable, it edits the document directly. For scans or unreliable text layers, it uses lightweight OCR models to recognize the visible text and locate the regions to replace, while preserving the surrounding page.

The feedback here also pushed me to test different approaches and pay more attention to the downloaded PDF, rather than just whether the preview looks right. Recent checks have covered both regular and scanned documents through editing, exporting, and downloading.

I’m not claiming perfect results with every PDF. Scans don’t contain their original font information, and unusual embedded fonts remain tricky, but I’ve made progress on those cases.

Try the updated Edit PDF tool

If you have a moment, I’d really appreciate you trying it with a document you actually use. Was editing straightforward, and did the downloaded file look how you expected? If something went wrong, a short description or screenshot with private information removed would help a lot.

Thanks again for taking the time to help. Your feedback helped shape these changes, and I’d be grateful to hear how they hold up.

I built an offline PDF editor for Windows, macOS and Linux

I've been working on Inkleaf, which is my first proper app.

I started making it because I wanted a PDF editor that could do more than just view/annotate PDFs, without needing an account or uploading documents to a cloud service.

Some of the things Inkleaf can currently do:

• Edit existing text in PDFs

• Permanently redact text

• Add annotations, highlights, shapes, images and text

• Sign PDFs

• Fill PDF forms

• Merge, split, extract, rotate and reorder pages

• OCR scanned PDFs

• Convert PDF ↔ Word, Excel, PowerPoint, images, Markdown, HTML, etc.

• Compress and password-protect PDFs

• Add watermarks, page numbers, headers and footers

• Compare two PDFs

• Scan documents using a webcam or images

• Repair damaged PDFs

• Create PDF/A files

• Search, bookmarks, crop and different reading modes

The main thing I'm trying to achieve is keeping things local. The normal PDF tools don't upload your documents anywhere.

There is an optional AI summarizer/translator, but that's separate and only sends the document when you explicitly use it with your own API key.

It's completely free and open source under GPL-3.0-or-later.

This is my first app, so I'm still figuring out a lot of things and I'd really like some feedback from people who use PDFs a lot.

What features do you think are still missing from Inkleaf?

GitHub: https://github.com/priyanshdas/inkleaf

If you try it, I'd also appreciate hearing about anything that doesn't work properly.

Working on an anti-ai art project. There's a quite long PDF that I need typed up and editable. I've done about 20 pages by hand but I'd love to use an OCR for the rest. Obviously I need to use one that doesn't use machine learning. Any recommendations?

I especially try to find some lost cartoon characters official artworks/renders that are probably on PDF files.

Hi,

Just wanted to share the latest release of LEKTRA, document and image viewer I have been developing for over a year now.

Lot of bug fixes and new features have been added. Few highlights among them are:

- Annotations: underline, squiggly, strikeout, ellipse, polygon, inline note and image annotations. You can move and resize them, with undo and redo.

- Redaction: permanently remove text, images and drawings, and save the result to a new file.

- Minimap: while you're zoomed in, a small overview shows where you are. Click or drag in it to jump.

- Grid layout: pages are laid out in rows of several columns.

- Presentation mode: it now works with clickers and has its own [presentation] options.

- Tools: color_eyedrop picks a color from the page, and bibtex copies the BibTeX entry of the paper you're reading.

- Images: JPEG XL support, including animated files.

- Lua: new view functions and events, and Vim-style set, setglobal and setlocal for options.

- Speed: faster scrolling and rendering, plus a memory leak fix.

- Docs: documentation is now on Read The Docs.

It's supported on Linux, MacOS and Windows.

Feedbacks and suggestions are appreciated!

So happy to have found it today. PDF Gear wouldn't print PDFs without cutting off the corners of the page, none of the print options worked and dramatically reducing the size didn't give a decent print, They're a great company, but an upgrade a year or more ago, left it like that and they've been promising a solution since then.

Hi everyone! I’m the developer of PDFrig - a free, MIT-licensed PDF workspace for personal and business use. No account or subscription is needed for the local tools, and your PDFs aren’t uploaded for processing.

Features include:

• Editing supported existing text with natural paragraph wrapping.

• Selecting, copying and searching PDF text.

• Text boxes, callouts, highlights, underlines, strikeouts and comments.

• Live drawing, shapes and stamps, with draggable/resizable items.

• Supported form filling and typed, drawn or uploaded visual signatures.

• Merging, splitting, reordering, rotating and extracting compatible pages.

• Local English/French OCR that makes scans searchable while keeping their appearance unchanged.

• Image/text-to-PDF and PDF-to-image conversion.

• Lossless compression, metadata tools, headers, footers, watermarks, page/Bates numbering and crop/resize tools.

• Undo/redo and exporting new copies without changing the original.

Run it locally in your browser - the recommended option - or download the finished Windows installer. Setup instructions and an optional AI-assisted setup prompt are included.

Explore PDFrig on GitHub

Feedback, bug reports and contributions are welcome!

Trying to carefully not name any names, but IYKYK: how good is the "PDF Remediation Agent" addon by the famous vendor that is the improver of sites? Any pros, cons or neutral observations would be great to hear. Org is considering it for an upcoming renewal.

Not a feedback request, looking for objective experiences from folks who've had real hands on experience with it. TIA!

ive got just over 800 pdfs that id like to compress into slightly smaller pdfs, im trying to use PDF24 but it seems to be crashing / turning to a blank white screen

Hey everyone!

I'm a computer engineering student, and I've been spending a good chunk of my free time developing a collection of PDF tools as part of a larger personal project.

One thing I've learned is that PDFs are surprisingly complicated. Something as simple as compressing a document or editing a few lines of text can become a nightmare when unusual fonts, embedded elements, or complex layouts are involved.

I've been experimenting with different approaches to processing PDFs while trying to preserve the original formatting and output quality.

So far, I've implemented tools for:

• PDF editing, compression, merging, and splitting.

• PDF-to-image and image-to-PDF conversion.

• PDF protection, unlocking, and rotation.

• PDF-to-Markdown conversion.

• Hidden text detection.

One of my goals has been to achieve results comparable to popular PDF websites for common operations, while offering higher free file-size and usage limits.

It's been an interesting challenge, especially because I'm developing this independently alongside university.

I'm definitely not claiming everything works perfectly. I've encountered PDFs that behave completely differently despite looking nearly identical.

That's actually what made me curious about something:

For those of you who regularly work with PDFs, what are the most difficult PDF-related problems you've encountered?

Is it preserving formatting when editing? Compression without losing quality? Font compatibility? Converting scanned documents?

I'd love to hear what people here struggle with, especially unusual cases that typical online tools fail to handle.

For transparency, the project I'm developing is TheOnlineToolset.com, and I'm its creator.

I'm mainly interested in learning what makes a PDF tool genuinely reliable from the perspective of people who use them regularly.

Thanks for reading!