Wherever possible publish in HTML format because it is the most widely accessible. If you publish in other formats:
- Always identify downloadable files with the file formatextension (.pdf, .ppt, xls, etc) and provide the file size.
- Some users may not have the software or plug-ins to open certain document types.
- Some may not be able to install software or plug-ins:
- Many organizations do not allow employees to installplug-ins and other software on their desktop machines.
- Plug-ins or software may not be available for the user’s operating system.
- Some users are not confident about installing new software or may not be able to manage the installation.
- Users may have a slow connection; downloading certain document formats is too slow or expensive (if they pay on the basis of connection time).
- Some formats are not fully accessible to visually-impaired people using screen readers.
PDF (Portable Document Format)
If PDF is used, an alternative accessible version of the content must be made available online. RTF (Rich Text Format) or TXT (text) format are acceptable alternatives. Although there have been significant accessibility improvements to the PDF format, a PDF document is only accessible when all of the following conditions are met:
- The original document was created in an application compatiblewith “tagged Adobe PDF” (for example, MS Office 2000+ or Pagemaker 7+ on Windows platform only).
- The original document was created with:
- Properly defined and styled structure (header styles,formatted columns, tables and lists).
- Text descriptions of images.
- Low security settings (you cannot disable editing or the accessibility features will be overridden).
- The conversion to PDF was done using Acrobat 5+ with correct conversion setup enabled.
- The converted PDF document has been manually checked to ensure the conversion process was successful.
- The blind user attempting to read the PDF document has access to appropriate screen reading technology:
- A recent version of a Microsoft Active Accessibility[MSAA]-compliant reader (JAWS or Window Eyes).
- An installation of Acrobat reader with accessibility functions and the necessary patch.
- The screen reader is running on a Windows platform.
As a result of these extensive requirements, PDF documents are not considered accessible.
Some web authors may put information online in PDF format in the belief that this protects it from unauthorized change or use. This belief is incorrect. Online content in any format is at risk of misuse.
As a best practice never post a Word document on the web, especially one that may have copyright issues. It is always best to convert Word documents to .PDF format for viewing on the web. There are times that Word documents are appropriate, especially if they have interactive components in them.
While the Microsoft suite of office products is standard on government operating systems, not all systems utilize Word. When Word documents are used try to provide the following:
- An RTF or TXT version as an alternative; RTF versions canbe very large, so use this approach with caution.
- Convert to HTML.
PowerPoint allows users to create powerful presentations. It has become a convention on the Internet to post PowerPoint files (.PPT format). The following steps can be taken to make PowerPoint files accessible:
- Do not clutter the slides with too much text.
- Use the built-in templates; take care to use only those with good color contrast.
- Do not use additional text boxes; only content that is visible in the outline view is accessible to screen readers.
- Describe images, graphs, charts and multimedia in notes (alert users that the notes contain content) or in a “hidden” slide; to hide a slide, right click on it in the slide sorter view and select the hide property.
Images and Graphics
Placing images or other graphic elements can improve the overall look and feel of a website. Key considerations in this process include:
- Ensure the image is the correct dimensional size for the space allowed. Never put an image that is 100 x 100 pixels on a page and resize it to a space that is 50 x 50 pixels. Not only does the quality suffer, but the file size data is that of the large dimensional size.
- Use the proper file type for the image – photo-type images require.jpg format, while flat color graphics are best represented in the .gif format.
- Don’t forget the “alt” tag – every image should have an intuitive “alt” tag that identifies the image or graphic in a short and descriptive manner.
Flash & Other Multimedia
- Always provide links to plug-ins or another support link necessary for the viewing of the file.
- Make it accessible.