Two years ago when Jakob Nielsen foisted an already out-of-date notion that warned people to avoid using PDFs online, we included as part of our coverage and response several commentaries from people far more enlightened on and experienced with the format. One of them was Robert McDaniels, an Adobe Systems staffer, who offered a thoughtful, point-by-point rebuttal of the usability guru's 2001 Alertbox column flogging the Portable Document Format as unsuitable for Web use. (He conveniently failed to mention that his own research group makes its for-profit reports available for purchase online in PDF.)
While PDF has gotten even better and smarter in the two years since, the same apparently can't be said for Nielsen, who last week drudged up that old opinion for a second time. This time Nielsen declared PDF to be "unfit for human consumption," as we reported last week.
McDaniels, an Business Analyst with Adobe, again wants to set the record straight by addressing specific Nielsen comments made in the July 14, 2003 column with some facts about PDF. He's kindly shared his most recent feedback to Nielsen with Planet PDF:
To: Dr. Jakob Nielsen
From: Robert McDaniels, Adobe Systems
Hi Dr. Nielsen,
I read your recent alertbox article and am disappointed in your approach to the use of PDF. While as an Adobe employee I would love to see everyone use Acrobat and PDF, even I realize that it is not some magic format that meets the needs of all types of media and presentation formats. Most PDFs are created from documents meant for print, and posted to the web to allow users instant access to these materials. This, however, does not have to be the case.
Many of the "PDF Usability Crimes" you cite have nothing to do with Acrobat or PDF but are the result of poor design choices. Most of same arguments about poor navigation, large file sizes, and excessive text blocks can be used to describe poorly designed HTML as well. There are some very valid reasons for using PDF's online as opposed to HTML. Some of these are:
Inclusion of 3rd person materials or non-HTML formats: If a web author has supporting materials like .DOC and .PPT files, it is easy to covert these to PDF rather than attempt to re-author the content for HTML. The files can then have usability features added to include things like navigation, file size optimization, and improved on-screen reading.
Accessibility: The Adobe Reader has several features that support accessibility like tagged documents, built-in screen reader, keyboard shortcuts, and high-contrast viewing. Many of the features are enabled automatically, and authors and users get more accessible documents with very little extra effort.
Document Security: On a individual document basis authors can protect document access and even the permissions for use of a document.
Offline access: Fonts, images, scripts, and now even media are all embedded in a PDF file. If I would like my user to save this information offline in a single file and preserve all functionality, PDF is the best way to do this.
As a usability expert I would have expected your article to address proper use of online PDF and how authors can enhance online PDF's to make them easier to use, not write-off the entire file format because you have seen bad PDF's on the web.
The "PDF Usability Crimes" and "Users Hate PDF" sections of your article contain many misleading statements. Some corrections to the statements are listed below:
LINEAR FLOW: The content and flow of a PDF is the responsibility of the author not the PDF file format. I can employ the same web writing guidelines you recommend into a PDF file.
INCONSISTENT UI: PDF's can be displayed Full-screen in a browser to hide the Adobe reader interface, and they can be embedded in HTML as well.
CRASHES: This is your second article that has mentioned excessive crashing, with no link to a study or evidence to support it. My personal experience is that the Acrobat plug-in is extremely stable, if you have other evidence link to it.
FILE SIZE: PDF file size is determined by the author. Images can be optimized automatically to produce fast loading files, and documents can be optimized for fast web viewing to allow page-at-a-time downloading of long documents. I've seen plenty of HTML pages that reference 1MB images.
SMALL TYPE: Again, type size is determined by the author, but Acrobat has the ability to zoom into areas of a document for easier reading, and text can be set-up as articles allowing the user to zoom into a flow of text and click to follow this text flow.
SEARCHING: The Reader's advanced search tools are an optional download. So readers who do not need them don't have to download the extra files. Even with the search tools a copy of the Adobe Reader is about the same size as the IE 6 SP1 download from Microsoft (13MB)
SINGLE PAGE LAYOUT: You can scroll through a PDF or view it page-at-a-time this is a user preference set by the buttons at the bottom of the viewing window.
NAVIGATION: I can build clickable buttons and links into a PDF. I can even mimic a website's navigation bar at the top of a PDF to make things easier for the viewer.
COPYING TEXT: You CAN copy and paste text from a PDF, but you can also apply security to a PDF in case you don't want your material to be reused too easily. What your user experienced was a secure PDF that intentionally did not allow some one to easily plagiarize its content.
The reality is PDFs have many of the usability features you promote. Just because most people choose to build PDFs for print rather than online consumption does not mean they can't. You say your next article will talk more about the proper use of PDFs online. I hope you choose to educate your readers on how to make their PDFs more consumable online with some of the features listed here, rather than just write-off the format for online use. Perhaps through helping educate people on how to properly use PDFs online you will start seeing more usable PDFs on the internet. If you would like more information on making PDFs better for online use there are numerous resources. Feel free to contact me if you cannot find the resources you need.
OK, so you want to stamp your document. Maybe you need to give reviewers some advice about the document's status or sensitivity. This tip from author Ted Padova demonstrates how to add stamps with the Stamp Tool along with related comments.