In this series of two articles, I provide a quick but complete guide to some simple steps you can take to make the PDFs — documents published online using Adobe’s Portable Document Format — in your e-Learning curriculum accessible, particularly to learners who use screen reader technology. This is not only good practice, it also results in better documents for readers regardless of their visual acuity, and it may even be necessary in order for your content to comply with laws where you live.
People with disabilities are already a very significant portion of the technology market, including the growing e-Learning landscape. With increasing disposable income, advancements in assistive technology, and the desire to further their education, students with disabilities are highly likely to be in your next virtual classroom — in fact, they’re probably already there!
Almost everyone uses computers as important tools in everyday life. This is especially true for communication. However, this technology can be a significant barrier to communication as well, particularly if it is difficult to use. Understanding how to remove barriers, especially with assistive technology, is a crucial step in accommodating the growing base of disabled users, including students.
As e-Learning becomes more prevalent, accessibility experts agree that PDFs are a good starting point for making the online environment more accessible. An accessible PDF makes information contained in it as easy to use by a person with a disability as it is for a person without a disability.
Why PDFs?
Portable Document Format (PDF) is one of the most popular formats to present and download documents on the Internet. Its popularity is due to its versatility of colors, fonts, and graphics derived from any source document that can be converted into a PDF file. Additionally, PDF documents offer protection from copying copyright materials and other sensitive information. Unlike other formats, a PDF document can be loaded and be viewed one page at a time.
Within the last few years Adobe, the creator of PDF, has made great strides in making the format accessible, starting with Acrobat 5.0 (Acrobat is the software that creates PDF files). Nevertheless, accessibility issues still exist that include the following:
- PDF files created with Acrobat versions earlier than 5.0 remain on the Internet. These files lack the proper mark-up and tags that screen reader devices and software need in order to interpret them correctly.
- Many PDF files are scanned documents and are therefore images. Unless the document creator processed those images through optical character recognition (OCR), screen readers cannot decipher them.
- In many cases, creators of PDF documents on the Internet today did not consider accessibility to be a priority.
The techniques I provide in this article and the next can assist developers in fulfilling the goal of ensuring that all PDF documents conform to accessibility standards. I break the process down into five steps, and these provide the structure of the articles. The steps are:
- Determine what kind of document you have, and decide how you can best make it into an accessible PDF.
- Make an accessible PDF out of your document.
- Tag the document. (I’ll explain what “tagging” is all about.)
- Evaluate and fix any problems that exist in the document after tagging.
- Add any other accessibility features that may be Useful
This article will address the first three steps, and will show you how to evaluate your document in order to identify any problems. The next article, to be published in March 2006, will outline the correction of any problems and how to add other accessibility features.
What kind of document is it, and how will you handle it?
PDFs can present serious accessibility problems for visually impaired learners who use screen readers — software and hardware that translates a page of text, tables, images and other visual information into audible form or into Braille and other tactile forms. In fact, in some cases, screen reader technology cannot process PDFs at all. To understand why this is so, it helps to understand that there are two different types of document files. These are text-based files and image-based files. The first step in the process of creating an accessible PDF is to determine which kind of file you have, and to choose an appropriate strategy for processing the file. If you are dealing with paper documents that you will scan, you will have to decide how to process and save the scanned image.
Text-based files
Standard word processing programs such as MS Word or WordPerfect create text-based documents. I am referring in this section to the electronic files, not to the paper versions of the documents. The best solution to achieving accessibility is either to convert such a file into HTML, or to leave it in its original version. Offering the document in different formats is also good standard practice. Screen readers have no difficulty with HTML, standard word processing formats, or text files. However, creating a number of different files in different formats for a single document can be tedious and expensive, and complicates maintenance of the information. Therefore, conversion of the word processing file to a PDF is often the most feasible, and practical alternative.
Text-based PDF file issues
Despite the potential for accessibility, text-based PDF files often are inaccessible, especially to screen reader users. Issues include:
- Lack of layout structure, such as heading tags
- Lack of table structure
- Lack of alternative text for images
- Lack of alternative text for forms
Image-based files
Image-based files are scanned images of hard copy, or paper documents. Screen readers cannot translate images into digital speech or tactile information. The best solution to achieving accessibility is to use an OCR scanner to capture and process the document image into a text-based file that screen readers can interpret correctly. However, OCR scanning may take several minutes for photographs. Furthermore, OCR scanned text may contain errors that require manual proofreading.
Another easy solution is to save scanned images as TIF (Tag(ged) Image File) format files, which can be imported into OCR software. In fact, some Web sites offer documents as both PDF and TIF files.
Image-based file issues
An image-based PDF document is a bitmap image without searchable text. If the document creator does not choose either the OCR or the TIF route, image-based PDF’s created from document scans will not be accessible to screen readers.
