ZIP files in PDF Portfolios

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Why can’t I add ZIP files to a PDF Portfolio?

Ok – so this isn’t exactly a developer topic but the question has popped up in my inbox with enough regularity that I thought I’d write an article about it.

You can try to add a ZIP file to a PDF Portfolio but then you see the warning dialog to the right. If you choose to click "OK", the ZIP file will be added to the PDF Portfolio. Great!

Actually – not so great. No one will be able to open or extract the ZIP from the Portfolio unless they hack their registry (Windows) or plist (Mac). So even though you were able to add the .ZIP file, it’s of very little use if you plan on sharing that PDF Portfolio with a broader audience.

The list of embargoed file types is a lot longer than just ZIP. You see the same warning if you attach EXE, VBS, BAT, DLL, or JS because they are associated with malicious programs, macros, and viruses that can damage your computer; the list goes on and on.

PDF Portfolios use ZIP Compression:

So here’s the good news, when you add a folder full of files to a PDF Portfolio guess what happens. That’s right – Acrobat uses ZIP compression to bundle them up. You don’t actually need to go through the process of zipping a folder full of files and then add the ZIP to the Portfolio. Just skip the zipping step add the folder directly to the Portfolio. The file size of the PDF Portfolio and a ZIP with the same set of files in it is virtually identical plus you get a great Flash UI to help people find what they need inside the Portfolio.