> In one of my alternative incarnations, I am a zoological taxonomist. > One of the big issues for taxonomy right now is whether to accept as > nomenclaturally valid papers that are published only in electronic > form, i.e. not printed on paper by a publisher. > > In a discussion of this matter, a colleague has claimed > > > [PDF files will not become unreadable] in the next 30-40 years. > > Possibly not in the 20 years that will follow. After that, when only > > 30-year and older documents are in the PDF format, the danger will > > increase that this information will not be readable any more. It is > > generally considered as quite unlikely that PDF will be readable in > > 100 years. Setting aside the paper/electronic argument, in terms of canonical files for documents intended for long-term preservation, PDF seems a very weak choice. Whether or not the actual files will "last" 100 years (I assume that we mean that they won't degrade to the point of nonreadability), using a proprietary binary format that doesn't readily convert to other formats seems a poor choice. Why not have the documents be sourced in one of the XML-based formats such as DocBook or DITA (well-documented, open, text-based, single-source publication formats)? Then you can have your PDF and preserve it too. (Donning tinfoil hat) You could even produce a handful of paper-based documents and hide them in caves around the world. Karen G. Schneider