Web Site Audience (Users)

Preface

Experts in accessibility point out that design changes made to help one group with a particular disability will generally benefit the entire web audience/community, even those without disabilities. For example, installing ALT tags to facilitate screen readers will benefit sighted users with the ALT tag pop-up information.

Grouping of Users by Disability

Physical- They may be unable to see, hear, move, or may be unable to process information of some types easily.

Mental- They may have difficulty reading or comprehending text.

Equipment- They may not have or be able to use a keyboard or mouse. They may have a text-only screen, a small screen, or a slow Internet connection.

Cultural- They may not speak or understand fluently the language in which the document is written.

Situational- They may be in a situation where their eyes, ears, or hands are busy or interfered with (for example, driving to work, working in a loud environment, etc.).

Interface- They may have an early version of a browser, a different browser entirely, a voice browser, or a different operating system.

Users with Visual Disabilities

Designing for the Visually Impaired

Persons who are blind or have visual disabilities have the most problem with the web because the web is such a visual tool. Most web pages we see today use a many graphics to convey a mood or attitude to a site. One way for us as web designers to help the visually impaired is to create high contrast between foreground and background colors, and to avoid busy background images. These are things we should always be aware of while designing a web page not only for the visually impaired, but for all users. An example of this would be to have a white background with a black text, and vise versa.

Designing for the Blind

We also might want to create a text-only version of our web sites. Textual pages are reasonably easy to access for blind or visually impaired users because the text can be fed to a screen reader that will read the text aloud through a synthesizer. Long pages are problematic because it is harder for blind users to scan for interesting parts than it is for a sighted user.

In order to facilitate scanning, it is recommended to emphasize the structure of the page by proper HTML markup: Use <h1> for the highest level heading, <h2> for the main parts of the information within the <h1>, and <h3> and lower levels for the even finer divisions of the information. By doing so, the blind user can get an overview of the structure of a page by having the <h1>s and <h2>s s read aloud, and can quickly skip an uninteresting section by instructing the screen reader to jump to the next lower-level heading.

Using Alt Tags Along with Images

Along with making your text easier to read, you also want the user to be about "display" your images to people who can’t see them. The easiest way of doing this is by provided an ALT tag to your images. Here’s an example of the typical HTML code for inserting an image into a page:

Users who have turned off image loading will see "Photo of Carthage Ruins" in place of the image. Blind users will have the text "Photo of Carthage Ruins" read aloud to them. The author doesn’t recommend that users use the ALT tag to make literal descriptions of images for web pages unless the user is an art critic. He would rather have you describe the meaning or role of the picture and how it relates to the text that is on that specific page.

It is also recommended that not all images need a description placed into the ALT tag at all. If it’s just a picture of image used for decorative purposes you should still place the ALT tag in there, but leave it blank. That would look like this: alt="". Meaningless image should have an empty ALT string rather than no ALT text at all because the presence of the empty ALT string is a signal to screen-reading software that it can skip the image. If no ALT text is present in an image tag, most screen readers would feel obliged to inform the user that an unknown image was present because there would be no way of knowing whether the image was important.

Web Site Updated December 8, 2000
Web Site Created November 20, 2000
By Bill Teysko, teysko@home.com
For CIS213, Cuyamaca College, El Cajon, CA
Url: http://www.oocities.org/webaccess2k
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