PDF

Adobe™ erweitert PDF und baut aber dabei zunehmend Sicherheitsprobleme und Inkompatibilitäten ein. Beim erstellen sollte man also nicht die neusten Features von Adobe nutzen!

Eigentlich ist eine PDF-Portfolio nur eine Sammlung von PDFs. Aber es bereitet den meisten freien PDF-Readern Probleme:

This is a portfolio - Adobe's proprietary extension to the pdf format designed to get you to use Adobe stuff. It has undocumented extensions to the pdf standard in it. It consists of a bunch of pdf's embedded in an interactive menu structure. If you get it to open, it'll probably turn out to be some sort of slideshow. They have been described as being like a flash application vomited into a pdf file. In any case it isn't standard pdf.
My google-fu tells me that okular does the best job of any open source pdf reader with these things. Apparently it open them and see all the parts but it can't play them as a slideshow.

Also mit okular öffnen!