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NOTE: 9/29/08 – I have added a few more resources about accessible PDFs at the end of this blog entry. If you find (or know of others) I will add them as well. Thanks to everyone who has commented.

I attended the Adobe Acrobat Users webinar a few weeks back and was pleased and satisfied that both what I have been doing, and what I have been advocating others to do, is the proper course of action.

This webinar did indeed introduce me to some of the more subtle nuances of Adobe Acrobat Professional that I was not aware of (although I am not sure if they are all part of the older version of Acrobat Professional that I own). But the dominant message – one that came across loud and clear – was the fervent appeal to create document that are accessible BEFORE converting them over to PDF (Portable Document Format).

In nearly all situations, an author considering the use of a PDF file will have created the original document in some other application. The exception might be a PDF “form” which one might create with Adobe LiveCycle Designer (not exactly Acrobat, but it comes with the Acrobat Pro package. Since MS-Word is the dominate player in this area, it is most likely that the PDF conversion will be from a Word document, but authors may be using MS Publisher, Adobe inDesign or any other document producing software.

I’ve already written about how to make accessible Word documents and other types of documents so I won’t repeat that information here. But I should note that there is a new White Paper from Adobe on Creating Accessible PDF with Adobe inDesign CS4 [PDF] that was just published.

The good news is that accessibly-designed document files will generally convert into accessible PDFs with almost no effort. But, the key here is that the original document has to be accessible first. And in most instances, the original document can very easily be made accessible by following some basic rules. Those rules fit into a nice acronym – H.I.T. The “H” stands for Headings, the “I” stands for Images, and the “T” stands for Tables. This is not to say that there aren’t other accessibility issues to be concerned about, but if the author attends to these three, they will be addressing the ones that often cause the most problems with users of Assistive Technology (AT).

Headings

Contrary to popular belief, the purpose of Headings in a document is not to make the font larger and more distinctive; the real reason is to create a semantic framework for understanding the relationship between and among the sections of content. The use of this semantic layout is essential for persons using AT.

When a person with a visual impairment, using a screen reader or some other AT device, reads a document, they most typically use the Headings to scan the document in exactly the same way a sighted person would scan it visually. Printers and typographers learned long ago that by changing the size, shape and spacing of the font, the reader can more easily semantically understand the organization of the document. The person with a visual impairment uses the hierarchical order of the Headings to semantically understand the document. Using a feature built into their screen reader, the user will simply jump from Heading to Heading to peruse the document. The hierarchical order of the headings cues the reader of the importance of the heading and the content that follows.

If you think of a typical textbook, the document starts with a title page that includes the name of the book and other identifying information (the name of the author, publisher, etc.). The most important information on that page is the title itself. For this reason, the title should always be Heading #1 and all other headings below this should be numbered Heading 2, 3, 4 and so on. While some will argue with me on this point, my general recommendation is to have only one Heading 1 in each document. My logic is that documents have only one Title.

In the typical textbook, there are usually a number of chapters and sub-chapters or sections. In our example, each of the chapter numbers and names would use Heading #2. Sub-chapters would then be styled with Heading #3 and sections within each would be Heading 4, 5, 6 as needed (Note: it is rare to see more that three or four sub headings in most documents). This is illustrated in Figure 1.

It is noted that different applications may call Headings by different names, but they all operate the same way. In Microsoft Word 2007, Headings can be found in the Styles section of the Ribbon. In Apple’s iWork Pages, the Headings elements are found in the Styles Drawer. And in Open Office Writer, the Heading can be found in the Styles drop-down bar.

Images

Images, whether they are on a web page, or in a word processed document, can present difficulties to many people using AT. Screen reading software, when encountering an image in a document, will announce the discovery by stating the word “image” followed by the alternative (or ALT) description provided by the author. Without the ALT description, the screen reader simply announces “image” leaving the user to guess what this means. This can be particularly problematic when the image in question is graphic text, that is, text embedded into an image such as in a logo. Even worse is when this image contains a hyperlink to some other resource. In these cases, without an ALT description, the screen reader user has to go to that new link to find out (or try to find out) what that resource is. It all makes for a rather confusing experience.

When creating web pages in HTML, the author is required to use ALT description for the image. But the author also has the option of using the “null” attribute – that is ALT=”" – which is a command to the screen reader to simply skip over the image completely. When creating other documents, whether they be word processed or PDFs, there is an option for adding a descriptive text to the image. However, unfortunately there is no capacity to make this a “null ALT” so all images must have a description.

As I have discussed in previous articles, most images in documents are simply “pretty pictures” designed to “catch one’s eye” and to make the overall document more visually appealing. They may be used as placeholders, to fill in white space, or to simply attenuate the topic of the writing. But in most cases, they add nothing to the understanding of the document. So choosing an ALT description for a PDF document can present some challenges. The general consensus among the designers I know is to try to keep ALT descriptions short and to the point. Here is a more thorough discussion on how to write good ALT descriptions.

Tables

Finally tables, or tabled data, in a document can present challenges to users of AT if the tables are not constructed correctly. To understand a table, the reader must understand the meaning of the data in each cell and this is typically accomplished by the use of column and/or row headings. Most tables use the top row of the columns for this heading information so most word processors software packages, when they create a table, will automatically assign this top row as the heading.

For example in Table 1, the first column contains the list of months; the second column the number of cars sold. A screen reader will read this as: Month, car sales, Jan, 67, Feb, 56, etc. In other words, the screen reader will read each cell starting in the upper left corner and read across the page to the right and then down to the next row.

In a large table with many rows and columns, a person using a screen reader could easily become lost in the data not knowing what row or column they are on. By the use of the “Table Mode” and special commands commonly found in most screen reader software, users are able to navigate around the table in various ways (e.g., reading columns or rows separately). But if the layout of the Table is not correct, the screen reader user can easily get lost in a sea of numbers and disconnected data.

Table 1.

Month	Car Sales
Jan.	67
Feb.	56
Mar.	34
Apr.	67
May	86
Jun.	56
Jul.	44

Therefore, tabled information in documents should generally be kept as simple as possible and the author must ensure that the layout of tables is constructed in such a way as to make the information understandable to all users. If a large complex table is required, it is best practice to publish this on a separate page in the document (or on a separate webpage if an HTML document). Ideally, a complex data tables should be kept in a spreadsheet application (e.g., MS Excel) and sent along as a separate document.

Converting Documents

Converting documents into PDF format can be done by any number of conversion solutions. Perhaps the most robust converter is the Adobe Acrobat PDFMaker, a plug-in that comes with the Adobe Acrobat Professional suite. However, I have discovered that when using Microsoft Office 2007, the Office Add-in: Microsoft Save as PDF does a much better job of converting Office files with fewer errors and faster results.

If you are using Open Office 3.1, the application has a built-in “save as PDF” feature. However, my experiments with this feature showed mixed results with most converted PDF documents failing to pass the accessibility test.

Note: As of this writing, I have only been able to test Apple iWork08. Regretfully, documents made by this application cannot be made accessible. I have ordered iWork09 and will report on those results on my blog as soon as possible

Testing Documents

Before making any PDF document available to the public, it should always be tested thoroughly for accessibility using the Adobe Acrobat Professional. Apart from actually testing the document with a screen reader like JAWS, Acrobat Professional is the only application I am aware of that tests PDFs for accessibility. Not only will the Acrobat Professional accessibility application test the page, it will provide detailed instructions on how to remedy any errors that are reported. For details on using this feature on Acrobat Professional, please visit the Adobe website or the Acrobat Users website.

Resources

Previous article about Accessible Documents

Accessibility resources from Adobe

Acrobat Users website

Here are some more web-based articles about accessible PDFs:

• Accessibility testing 14 PDF creation tools by Ted Page of PWS
• No Fuss Accessibility by Antonio DaSilva
• Are PDFs more important than web accessibility? by Mark Magennis