9 June 2001

In his June 10 "Alertbox" column, Internet usability consultant Jakob Nielsen strongly recommends against the use of PDF for documents intended for on-screen reading. [Share your opinions in the PDF-TalkBack conference within the Planet PDF Forum.]

"Forcing users to browse PDF files decreases usability by around 300 percent (his 'rough estimate') compared with HTML pages," he says. "You should only use PDF for documents that users are likely to print."

Nielsen offers six basic guidelines to help minimize usability problems when publishing in PDF, including "sticking to version 3 until 2002."

In the same column, Nielsen demonstrates a glaring unfamiliarity with the PDF file format, using the acronym interchangeably with the name of the Adobe application used to create and work with PDF documents.

"PDF version 5 was released recently," he writes, presumably referring to Acrobat 5.0 that began shipping in April 2001. He sticks to using "PDF 3" and recommends others do the same; it's unclear whether he's referring here to the full commercial Acrobat product or the free Acrobat Reader. The latest version of the PDF specification is version 1.4.

In either case, using a more than two-year-old version may well explain some of the problems he and others he cites as doing the same have allegedly encountered. It seems a bit of a stretch to find fault with a technology when your own use lags behind by several generations.

Nielsen cites as evidence of PDF's difficulties the results of a study on how journalists use the Web, in which "we found that PDF files sometimes crashed the user's computer." (Couldn't possibly be any cause other than the PDF?) He also imagines flaws where they don't -- or don't need to -- exist, such as his comment that "PDF pages lack navigation bars and other apparatus that might help users move within the information space." He only recommends the use of PDF with documents of five pages or more, while at the same time finding fault that "PDF documents can be very big." Of course, that misses the point that the PDF version of a Web document includes all the graphical and fonts elements, as well as the text.

Most of the alleged weaknesses cited in the column actually have more to do with user error -- poor authoring techniques and lack of understanding of PDF -- than with problems inherent in the format.

His best points have to do with not confusing users -- by indicating that a specific link will open a PDF document rather than another HTML page, and by clearly identifying how and where to download the free Acrobat Reader.

PDF has its weaknesses, for sure -- as does HTML -- and as do Web browsers. And usability gurus, too, as Nielsen aptly demonstrates.

MORE INFO

• Jakob Nielsen's Alertbox column for June 10, 2001.

• Read a rebuttal of the column by an Adobe Systems application engineer.

• Read another user-submitted opinion that takes a middle-ground position.

• Share your opinions in the PDF-TalkBack conference within the Planet PDF Forum.