Though it stands for Portable Document Format, PDF might as well stand for Printable Document Format. That’s because printing is just about the only thing a PDF is good for.

OK, that might sound a little harsh… but for reasons well elucidated elsewhere, PDF is a poor choice of document if:

1. The document is longer than a few pages in length
2. The document is going to be read online

Most technical documentation for software falls into the above categories. This isn’t to say that there is no place for PDFs in technical communication…it is just to say that PDFs should be used for what they do best: facilitating the printing of content.

When I try to read PDFs online, I regularly encounter the following:

• Acrobat hangs Firefox. Yeah, isn’t it lovely having to kill the Firefox process, relaunch Firefox, find the page with the link to the PDF, and try to open it again just to find that one piece of information I need to accomplish what it is I am trying to do.
• Acrobat hangs itself. This doesn’t happen as often as the above, but it IS still frequent enough to give me that “will it work this time?” feeling any time I open a PDF.
• In addition to that, if I do get the PDF open without crashing anything, I have to search the document. Opening the PDF to the cover or title page doesn’t do anything for me. Searching, of course opens a sidebar search that inevitably obscures some of the content. This sidebar, is, of course, persistent… If I go to search another PDF document, the same search term from the first PDF is still in the sidebar.
• Some PDFs are constructed to dynamically download content from the web as I jump from page to page. This is infuriatingly slow and cumbersome.
• Using the sidebar scroll control to scroll vertically throughout a PDF document jumps between pages. Why can’t it scroll the document as I move the location bar?
• If the PDF opens embedded in the web browser, it breaks all sorts of usability features I’ve come to rely on. What does File->Print do in the menu? What does File-> Save do in the menu? Why doesn’t it ever do what it should?
• It inserts another toolbar in the browser that I’m not used to working with. On top of that, it’s cluttered with buttons I never use (unless it’s the Save button that I inevitably use AFTER trying File-> Save).
• Toolbar buttons use non-standard metaphors. Why is the Search button a set of binoculars and not a magnifying glass like every other Search button? Every time I look for the Search button in Acrobat, I see the binoculars and it registers as some sort of Zoom feature and not a search feature.

The best solution, of course, is to provide content in both HTML (familiar web-paradigm) and PDF format. This lets users access the web version of content for reading online, while providing them an effective mechanism for killing lots of trees if they want to print out the whole thing.

If you are writing technical documentation, single sourcing to both web and PDF should be on your roadmap…as it is the right thing to do for your readers. If you have to choose between one format or another, think long and hard about it. Go PDF-only and you make all your documentation that much less accessible, but placate those who would want to print it. Go HTML-only and you’ll be doing right by your users (even if they don’t know it), but prepare to hear people complain if you don’t provide an easy mechanism to print out all the content (a feature that is sorely lacking from most web help systems).