Blurry PDF in Clop

Thanks u/Snooty_Folgers_230 for the heads up! Optimising a PDF is mostly a matter of lowering the DPI of the images inside it, which will make them blurrier because they have a lower resolution after compression. In Clop, normal optimisation keeps the image DPI the same and tries to only apply lossless optimisations like removing unnecesarry fonts, re-encoding the images with a newer JPEG encoder etc. Not all PDFs can benefit from this, based on their content they might be all images so there’s nothing left to losslessly squeeze out. Aggressive optimisation does actually lower the DPI to 150 (usually it’s at 300DPI) which is like making the images 0.5x in resolution. I’m guessing PDFSqueeze might be choosing a higher DPI which is why you see a difference in quality. In Clop v3 you’ll have the option to select the DPI yourself from the minus button in the floating result or as a persistent setting. We have a beta right now on the Discord channel The DPI selector might not yet be released in the current beta, I’m trying to release it in beta2 as soon as possible. EDIT: beta 2 with the PDF DPI picker released here: https://files.lowtechguys.com/Clop-3.0.0b2.dmg By default, it uses lossless optimisation. Aggressive optimisation will lower the DPI adaptively based on the images present in the PDF. Click or drag the minus (-) icon of the floating result to select a different DPI, right click on the result and select Compare to see the difference.

Thanks! being a solo dev, marketing is the hardest part, I try not to be spammy!

Mixed raster content (MRC) compression is an advanced image compression method that segments a document into different layers, such as text, background, and images. Each layer is compressed separately using the most efficient algorithm for its content type, and then the layers are combined to reconstruct the original document. Interesting, but it's the same thing that Clop does, only without the buzzword naming. Internally, Clop calls Ghostscript (a PDF decoder/encoder) with carefully chosen params which: extracts images, downsamples them if needed, re-encodes with higher JPEG compression factor, converts CMYK to RGB, detects grayscale images and encodes them as such, de-duplicates extracts text, embeds, subsets and compresses non-standard fonts, drops standard always-available fonts extracts page data, compressed binary streams with LZW, drops comments, EPS info, halftone info, strips metadata I checked a very large book on AvePDF and the only thing it did noticeably was lower the image DPI down to about 72-100 range (hard to tell the exact DPI on PDFs as each image has its own DPI), while Clop keeps them to 150DPI. To be honest, in all my tests, the only thing that does have a real benefit on PDFs is lowering the DPI on image heavy PDFs which Clop v3 will do adaptively based on the detected DPI, and allow you do lower based on your size needs. Even their examples are simply DPI lowering at max, like for example this datasheet: https://www.gdpicture.com/downloads/hyper-compression/text-transparency.zip Before hyper-compression After hyper-compression (no smoothing) 1 MB 22.9 KB They are starting from a highly uncompressed JPEG, which obviously makes the size difference huge in comparison. Sure, their PDF is 23KB but it is also a blurry and downscaled mess as you can see in this screenshot They do have a better JPEG encoder lib than Ghostscript, if I go to 100DPI (which seems to be their target in that example) I can only get down to 108KB, as opposed to their 23KB. So I'll have to look into integrating JPEGli again, that should help. Last try was not very successful.

Yep Clop v3 is coming soon 😊 all my upgrades are free, I never release paid upgrades.

The macOS native answer for the compression side is underrated: Quartz filters via ColorSync Utility. macOS ships a "Reduce File Size" filter that's overly aggressive, but you can duplicate it in ColorSync Utility, raise the JPEG quality threshold, and save your own. It then shows up in every Save-as-PDF dialog and in Preview's File → Export. Quality stays much better than Clop aggressive at similar file sizes, and it's free and built in. For the automation side, Hazel is the missing piece. Folder watch on Downloads, match on .pdf, run your custom Quartz filter via an Automator action, then chain ocrmypdf for the OCR step. You get "PDF lands → gets compressed → gets OCR'd → gets renamed" without ever touching it. If wiring up Hazel + ocrmypdf is too much fuss for the OCR part specifically, I made Formattery — runs OCR on-device on Mac, batch a whole folder at once. No folder-watching automation built in (Hazel is still the answer for that), but it fills the gap if you want a one-click OCR without the CLI tooling: https://apps.apple.com/us/app/formattery-file-converter/id6759955312

That’s an excellent way to promote your app. I wish more people would follow your lead. Well done!

Would love to see MRC compression like avepdf. Not simple, but would instantly make clop hard to beat if done similarly, as I’ve yet to find a competitor to avepdf that is anywhere near as capable when doing my app comparisons. I just don’t promote them much because they offer a buggy webapp that fails half the time, with terrible customer service. But when they work, the downsizing without visible degradation can be impressive. Often 80-97% size reductions with almost no visible difference for scanned documents on low. I’ve used it on keynote pdf exports a lot too, which I mention as an easy to test/replicate option.

The dev has been very responsive here in my experience. He might respond u/alin23

Wait, there will be Clop v3 soon?! Congrats 🎉 I use Clop almost everyday and I can’t imagine my Mac without Clop. Might I ask, will I have to pay to upgrade to the latest version? If so, how much do I need to pay? I hope my questions don’t offend you.

It really depends on the pdf what you can do. Some pdfs are just a bunch of images tied together (often book scans). It’s literally just jpegs. When you compress them, you are recompressing the JPEG files, which are already a lossy compression format (although they’re amazing for photos). A good pdf on the other hand is just text and layout information, not much to compress, already small. There are some pdfs that bundle in files, fonts and full resolution photos, where you can take some things out and the photo compression won’t be noticeable and you can gain quite a lot. Your real options are the following: OCR the pdf and save as text (markdown for instance, using Marker) get the content from a different source, where it’s not a scan

Already replied regarding the dev. Do your PDFs have an OCR layer? I’ve a lot of PDFs that do not. They are optical scans from very limited run texts. Compression on a PDF without an OCR layer will be limited without making the text blurry. Most of the texts I have which are optical scans are either non-Latin alphabets or are mix of many languages both Latin based alphabets and non-Latin. I’ve yet to find a way to get a good OCR for those. I would guess not having an OCR is the issue you are having. Getting a decent OCR would help here immensely. Hope you get an answer.

For this workflow I would separate three jobs: compression OCR/text layer naming/filing Clop is mostly solving #1. For scanned PDFs, aggressive compression will always be risky because the page is often one big image. Lower DPI means smaller file, but also softer text. For #2, if you need the PDF itself to become searchable in Preview/Finder/DEVONthink/Paperless, I would use something that actually writes an OCR text layer into the PDF. ocrmypdf is the boring reliable option if you are okay with CLI/Hazel. ABBYY/Prizmo/DEVONthink Pro are more app-like options. I would not compress first, then OCR. I would keep originals, OCR first, then test compression settings on copies. Scanned documents are too easy to damage silently. Disclosure: I’m Josef, building NameQuick. I would not use it as a Clop replacement or as the tool that embeds the OCR layer into the PDF. The relevant part is after/alongside OCR: read the document content, suggest names like 2026-06-14 - Vendor - Invoice.pdf, preview the batch, then move/tag/archive. If your main goal is “PDFs become searchable everywhere,” use an OCR-layer tool first.