Originally published: Sep 29, 2009
You probably already know this, but just in case . . . PDF stands for portable document format . PDF was invented by Adobe Systems, Inc. (www.adobe.com), as a way to publish documents that anyone can read, regardless of whether they are working in the same operating system or using the same software that the document’s creator worked in.
A PDF file keeps the layout, page breaks, and fonts of the original document. With PDF, you can have a document that looks the same whether you send a paper copy to someone or that person prints it from the web.
Anyone who has Adobe Acrobat Reader on a computer can open, read, and print the document. Most new computers today come with Acrobat Reader already installed, and Adobe allows free downloads of Acrobat Reader from its web site. Anyone who is comfortable downloading and installing software can have a copy.
I’m not going to say, “Never put up a PDF file.” As always, it comes down to your goals, your audiences, and their scenarios.
However, realize that, with most PDF files, you are providing a paper document on the web rather than web-based information. If the document looks like a paper document or if it is large, people are likely to print it rather than read it on the screen. You have distributed the document; you have saved the printing and shipping cost; you have shifted the cost and effort of printing to your audiences – but have you really met their needs?
If you are using the web to distribute journal articles or other material that you expect people to print and use on paper, and if your audiences are comfortable with PDF files, PDF may be the right way to go.
The web is a great distribution mechanism:
Distribution is the great advantage that the Internet has over paper, even for paper documents.
However, PDF documents are often not the best way to create a useful and usable web site. Break documents into non-PDF pieces -
If people come to your web site for information – not for documents as a whole, but for only some of the information in those documents – a PDF file defeats the very purpose and nature of the web.
Yes, PDF files are searchable. But people don’t want to first navigate or search to get the document and then search again within the document. They want to navigate or search directly to the specific information that they want. And many people don’t know how to search in a PDF document.
And yes, you can divide up a PDF document and give it a linked table of contents so that people who know how to open the index list can jump to a specific place in the document – but only if you have set it up well. Most PDF files are just put up on the web, with no attention to internal links.
A story: I was getting information from the web site of a government agency when I reached a point where I needed the physical address of one of the agency’s regional offices. A link on the page said it would take me to a list of the regional offices. What would you have expected to happen by clicking that link? I expected a single page with a list of offices. To my surprise, Acrobat started to open. I waited, as one must, and a document opened that had nothing at all to do with regional offices. It was a report on something totally different from the topic I was getting information about. My first thought was “wrong link,” but curiosity led me to at least look quickly through the document. Sure enough, an appendix 20 pages later was the list of regional offices I needed.
That’s not a good use of PDF. If the link promises a list of offices, take the page out of the paper document and make it a separate (not PDF) web page.
Why make the document look just like paper if it is not meant to be used on paper?
For example, a two-column layout works very well on paper. It doesn’t work well on the web if you can’t see the entire page without scrolling. On the screen, people have to scroll down while reading only halfway across the screen and then scroll up again to read the second column.
A document like the U. S. Department of Agriculture Issue Brief in Figure 5-14 just begs to be printed and read off-line.
Figure 5-14: A two-column PDF document does not work well if readers have to scroll to read the columns
If you have a public audience, don’t assume that a PDF file is acceptable. Not everyone has Acrobat Reader. Not everyone is willing or able to download and install software even if it is free. In usability testing that I did in 2004 on information about cancer, more than half of the public participants – cancer patients and their family members – were unwilling to select the PDF option. They said they saw the PDF symbol all the time, but they didn’t know what it was and never chose it. They had never downloaded programs onto their computers, and they were leery of doing so.
Even people who have computers that come with Acrobat Reader may be uncomfortable going to PDF files. For people with dial-up access or slow machines, a PDF file may take a long time to open.
PDF files often open in a second window, and second windows cause problems for many people. They want to back out of the file that came up, but Back isn’t available – and they don’t realize that they now have two browser windows open.
For many years, PDF files did not work well for people who use assistive software, such as screen-readers. That has changed. Adobe
Acrobat 8.0 supports tagging so that accessibility software can read a PDF file.
But . . .
A typical PDF page is in portrait orientation. Most web users are looking at landscape-oriented screens.
Users have to learn yet another way of navigating, another way of printing, another way of searching.
As a web content specialist or a web developer, you may be comfortable going back and forth among different browsers, even though that means changing where and what you click on. Are the people you are writing to all equally comfortable doing that?
If the author was in “paper mode” – in “document mode” or “book mode” – when writing what becomes the PDF file, it’s very likely that the writing isn’t going to work well on the web. The paragraphs will be too long. The headings will be too sparse. The author will have probably assumed that people coming to the document will read it from first page to last.
If some site visitors want information on the screen and others want entire documents, offer both. Many sites do.
When you link to a PDF, tell people that’s what they are getting and how large it is or how long it will take to download.
Figure 5-15 shows you how employees at the U. S. Federal Aviation Administration can choose to download a PDF of their entire web content standards or get an HTML page on specific topics in the standards.
Figure 5-15: This intranet site offers the whole document as a PDF and also offers each topic as a separate web page.
Here are key messages from Chapter 5:
Do you use PDFs on your site? How do you determine when to use a PDF? Do you offer the same information on the screen and in a PDF? Share your thoughts at the UIE Brain Sparks blog.
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