PDF had an open spec and oodles of programs supporting it. I don't understand where this comment is coming from.

Adobe acrobat (and maybe reader) is really the only app that fully supports the full PDF spec as understood by the authors of the spec. There are ridiculous parts of the spec that allow support for things like JS, etc.

I don’t think it’s ridiculous to want a scriptable document, especially for complicated forms. Likewise for the other much-dragged features for 3d scenes.

https://pdfa.org/resource/pdf-in-manufacturing/ is a great usecase.

The PDF spec even supports attachments in PDF files.

How does that work exactly? Is it widely supported?

I recently had to add an embed feature to our pdf rendering, to allow users to embed other pdfs inside the one we generate for them. Since we use headless Chrome, I used pdfjs from mozilla to render the embedded pdf on screen before generating the pdf, so you can actually see and read the embedded pdf.

Works pretty well, but was wondering about this attachment feature of pdfs.

PDF is a container format and yoy can just shove files in there. pdftk supports this with attach_files, and at the very least the linux pdf readers I’ve used know how to deal with them.

TIL!

Since these pdfs end up in whatever and how old devices, I'd rather not risk it though.

good question. how it works is an implementation question. read the PDF spec (big, and somewhat hard to grok in parts) or Google about it. I don't know. I just knew about the fact, because I have done some work with PDF. also don't know if it is widely supported, sorry.

nice idea there.

What's wrong with using a sane subset of the spec aka PDF/A?

I've seen many third party PDF viewers; I think all supported JavaScript. It's commonplace, not 'ridiculous' at all.

> Adobe acrobat (and maybe reader) is really the only app that fully supports the full PDF spec

The full spec is large and afaik has many obscure pieces, including 3-D, etc. Like many specs, they don't match reality and nobody takes completeness too seriously. For almost all users, supporting the entire PDF spec doesn't matter (does it matter for any user - does any person or organization use the entire spec over their lifetimes?).

Also, do we know that Adobe supports the entire spec?

Yeah, even Adobe doesn't really use the full spec. Or at least didn't.

There's a fairly big chunk in the spec of special presentation attributes for slideshows. When I implemented them I was surprised that slide shows produced by Acrobat didn't work. Well, obviously my implementation was buggy.

Er, no, Adobe didn't use their own slide show attributes for the slide shows produced by Acrobat. They used JavaScript instead.

Oh well. ¯\_(ツ)_/¯

That is true, but I have never encountered a PDF that is not produced by me and cannot be faithfully represented in third party PDF readers. And I give up the idea of producing those kinds of PDFs because I know the people I send to will complain about me rather than their PDF readers. So, Adobe Acrobat doesn't have any monopoly power here, since almost no one cares about those things only they can do.

We often get PDF's that does not work in our pipeline and it's always blamed on the pipeline, not on the creating software. The user usually converts the PDF to an image with adobe reader and screenshot, load up Libreoffice, paste and export it as PDF archive.

So the PDF that does not work in your pipeline is created by LibreOffice rather than Adobe Acrobat? That doesn't seem to add any strength to the argument that "Adobe Acrobat has unusual powers because only it can handle the full spec of PDF".

No, you missread. The PDF that works is created by anything that does not use the full spec of new PDF versions. We have chosen Libreoffice because we already use it for other things. If we recreate the PDF in Libreoffice as PDF archive version it works just fine. The problem is usually a pamphlet created by some ad agency using the absolutely latest version of some layout program, neither adobe nor libreoffice. The PDF usually works just fine in Adobe but not in our pipeline that uses all sorts of linux programs to process into a JPG in the format and orientation our system needs. Noone has had the time or energy to fix it since most stuff works so for now it will be downsampled by a screenshot and just showed into the system. The added benefit is the PDF shrinks from 150 MB to 300 kB in the process.

Adobe Acrobat is the only thing that can handle all cases yes. All other programs uses (different) special cases each and most of them fail in some edge cases. It can be funny letters showing up because of fonts not working properly or images disapearing or all sorts of things. I have given up to fix them all. I still have a library of PDF's that we used to run through to try to get as many as possible to work.

> That is true, but I have never encountered a PDF that is not produced by me and cannot be faithfully represented in third party PDF readers.

That's because PDF is well designed and has a fallback for advanced page elements so more primitive readers can still render them.

Agreed. Also, possibly the most commonly used reader is pdf.js, the FOSS component used by at least some major web browsers.

I'd guess it's the fact that nothing supports editing PDFs except Adobe Acrobat. Not to any sufficient extent. LibreOffice Draw kinda try to do it but also corrupts the file IME.

Edit: Apparently some people can edit PDFs reliably with MacOS Preview.app, LibreOffice Draw or pdftk.

Where are people getting this information? There are many applications that support edting PDFs, more than I can remember.

Foxit Phantom is pretty good

It costs, I might aswell pay for Acrobat.

What if Foxit works better and costs less?

That’d be interesting but I’m not the right audience. In which ways is it better than Acrobat?

IME: Much faster, far better UI. (Foxit is one option of many.)

Does that one have a name? I’m a MacOS transplant and have never gotten terribly familiar with the territory. Thanks!

Preview.app which owes its heritage to NextStep. https://en.wikipedia.org/wiki/Preview

... ah, thanks, I misread. I thought GP was talking about a document format in the same space as PDF that was native to MacOS.

Preview is the app on macOS that lets you view and even edit PDF files.

preview.app

I find Chrome's built-in PDF viewer much snappier than Adobe Acrobat.

Sadly I had to install Adobe Reader on my father PC again after he had documents* with formulas. Chrome would calculate the numbers wrong. Everything was off by 10.

*To get reimburses from a union or something.

Whoa, I had no idea PDFs can have formulas.

You can embed Javascript in PDFs

If you occasionally need Adobe Reader/Acrobat exclusive features but don't want to install, you can use the free online version of Acrobat. It's pretty decent though it doesn't have all the features:

https://acrobat.adobe.com/us/en/

I recently had issues with macOS‘ Preview.app and formulas. It’s a nice feature, but probably not widely supported.

It’s incredible to me that not only has Preview.app been the best non-Adobe way to use PDF’s for decades now and only on macOS (perhaps because NextStep, its roots, used PostScript natively?) but that Linux actually also seems to have better tooling in this space than Windows (where you’re pretty much stuck with Adobe Reader if you want a free solution)

Isn't SumatraPDF a decent program for Windows?

In regards to Preview, I still find it insane that it doesn't have an iOS/iPadOS equivalent. Bits of the functionality are scattered all over the place, usually in ways that don't feel as good as they do on the Mac. Sometimes I just want to open a PDF and leave it open, and not have to do it from Files which assumes I want to do something else with it than just looking.

I personally use SumatraPDF on Windows, but it's basically just a fantastic PDF viewer. It does little else in regards to editing/modifying PDFs. Even the PDF viewer in Edge does more.

But for a lightweight, bloat-free experience, SumatraPDF is the way to go.

> Preview.app been the best non-Adobe way to use PDF’s for decades now

Where is all this stuff coming from? Why would you say Preview is the best? Foxit? Nitro? Their are endless PDF applications much more powerful and capable, some designed for professionals.

For annotating and adding a hand drawn signature to PDFs, preview really is the best: lightweight, straightforward, free, comes with the OS. I don’t know any comparable app for Linux (or windows although I rarely use it)

https://simplePDF.eu will be the closest « Preview-like » experience on Linux (and any OS really).

It’s local only (the document you load and data you fill in never leave the browser) and free

Disclosure: I’m the developer behind it

Any plans on implementing redaction?

If the background is white, it’s already possible: https://simplepdf.eu/help/faq/how-to-add-background

For other colors, it’s in the backlog!

(I’d aiming to automatically provide the correct color by inspecting pixels within the area to redact, to make it as simple as possible)

Yeah but hiding the information versus removing it is two different things. By hiding it, the information is still there but hidden.

"Best" isn't necessarily the same as "has the most features".

I think many people find that Preview.app does everything they ever wanted to do with PDFs. It really is surprisingly capable. It's also fast and far less convoluted than most PDF tools I have seen.

And of course it comes free with every Mac, which often makes it "best" in terms of value for money.

It doesn't help that many PDF editors (including the two you mentioned) are full of the most ridiculous pricing shenanigans.

> many PDF editors (including the two you mentioned) are full of the most ridiculous pricing shenanigans.

What shenanigans? On one computer, we have a 15 year old version of Foxit running as good as new, no further licensing needed.

Pages and pages of dark patterns with the sole purpose of misleading people into buying some "plan" that nobody could possibly want at prices more expensive than the entire Microsoft Office suite.

Could you name a service that does it and give an example?

I see that much more with Adobe than with anyone, fwiw.

The Foxit PDF Editor product page is one example (not the worst by far). It suggests prominently that you have to buy an annual subscription ($109 to $159 p.a unless you can live with the cloud option for $59 p.a). Microsoft Office 365 Personal is $69.99 p.a including 1TB cloud storage.

https://www.foxit.com/pdf-editor/

The one-time license option is hidden away in a product comparison table (and linked to in a few other far less visible places).

Nitro, the other PDF editor you mentioned, appears to offer only a one-off purchase:

https://www.gonitro.com/pricing

But it says "for Windows" and at the top of the page, there's a promotion saying "Get up to 1 year subscription - free when you switch to Nitro". So there is a subscription after all?

If you keep scrolling down to the FAQ and there's a question asking:

"Is Nitro available as a subscription or a one-time purchase?

Nitro Pro, ideal for individuals and small to medium sized teams, is available as an annual subscription."

No mention of a one-time purchase option. So which is it? I'm confused. Is this "one-time purchase" a perpetual license or does it stop working after a year?

These are certainly not the most egregious examples of pricing shenanigans. But given the recent history of companies going subscription-only, this is enough uncertainty for me not to buy.

> perhaps because NextStep, its roots, used PostScript natively?

And OS X and its successors use Display PDF natively, which is why it is trivial to save almost anything that can be displayed into a PDF file. The PDF stack that Preview.app leverages is a foundation of the OS itself.

What a bizarre comment - Preview.app isn't even the best PDF software on Apple platforms (it's more likely something like Readdle's PDF Expert).

There are of course better softwares than the Preview.app, but that's if you are willing to pay for it. Preview.app is free.

What about Okular?

There is no support for redacting text properly on Okular.

Adobe is expert at software standards. They aren't compulsive about control, yet don't give the farm away. The know when to be open and how much. That is how they dominate.

Could you give an example? PDF is an open standard controlled by ISO and has been for awhile.

PDF has been a free-as-in-beer standard since 1993 and a free-as-in-speech ISO standard since 2008. The reality is that PDF is open, reliable, useful, feature rich, and widely accepted. It has no serious competitors.

There's a reason why, unlike raster image formats, there aren't any serious competitors. The thing to realise about printed page file formats is that even if you set aside all of the silly "multimedia" and "interactivity" features, there's still a gargantuan rabbit hole of non-trivial features that need to be implemented absolutely perfectly, from kerning to spot color. PDF does it all very well. There's really no scope for a competitor to come along to make something that's obviously better.

>PDF has been a free-as-in-beer standard since 1993 and a free-as-in-speech ISO standard since 2008.

Yes. The first sentence of the Wikipedia article about PDF is:

>Portable Document Format (PDF), standardized as ISO 32000, is a file format developed by Adobe in 1992 to present documents, including text formatting and images, in a manner independent of application software, hardware, and operating systems.

And the last sentence of the first paragraph of the same article is:

>PDF was standardized as ISO 32000 in 2008.[5] The last edition as ISO 32000-2:2020 was published in December 2020. .

Especially since there's a PDF/A standard subset for archival, which makes those documents readable decades after any other format would rot.

> PDF/A standard

Yes, the United States Library of Congress makes heavy use. I imagine their evaluation process to select a digital archive format is very tough!

Warning: Preview has a very, very nasty PDF-damaging bug. After applying a signature to a PDF in Preview, the searchable text layer becomes scrambled so that numbers are no longer searchable or copy-able. For example, “$745.25” would become something like “$;@€:-€“. The document would still look correct, but you could not search for that figure or copy it out of the PDF without instead getting the garbled version.

There are two open competitive formats to PDF:

- OpenXPS (https://en.wikipedia.org/wiki/Open_XML_Paper_Specification)

- EPS (https://en.wikipedia.org/wiki/Encapsulated_PostScript).