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CPB/WGBH National Center for Accessible Media
WGBH Educational Foundation
125 Western Avenue
Boston, MA 02134
Voice/TTY: 617 492-9258
FAX: 617 782-2155
For millions of people around the world, the World Wide Web is an exciting new tool for learning and communicating. For millions of deaf, hard-of-hearing, blind or visually impaired computer users, however, the Web's enhanced graphics, audio, and video capabilities are out of reach.
An initiative announced in January of 1996 by the CPB/WGBH National Center for Accessible Media (NCAM) aims to change that. Known as the Web Access Project, its mission is to research, develop and test methods of integrating access technologies (such as captioning and audio description) and new Web tools into a World Wide Web site, making it fully accessible to blind or deaf Internet users. NCAM uses WGBH Online (http://www.wgbh.org)-- the public broadcaster's Web site which is visited by more than 2,000 users a day-- as its test-bed for research and field-testing solutions. The Web Access Project has been made possible with the support of the Telecommunications Funding Partnership for People with Disabilities and The Boston Foundation. In 1997, an extension of the project to public broadcasting web sites is funded by the National Telecommunications and Information Administration of the U.S. Department of Commerce.
The World Wide Web
Just one part of a vast electronic resource known as the Internet, the World Wide Web is a place to go for information on virtually any subject imaginable. The Web is not a physical entity; rather, it is a huge network which can be entered from any computer that has access to the Internet. For example, if you have a modem and an on-line account with Compuserve, America Online, Netcom or one of the many other on- line or Internet service providers, you can have access to the Web.
A Web site is a series of electronic pages filled with text, graphics and images, similar to a book or magazine. Web sites are made visible on your computer through the use of a "browser", special software that allows you to navigate the Web. Popular browsers include Netscape Navigator and Microsoft's Internet Explorer. By typing a Web site's address into the browser, you can enter the site, look around, download (or copy) text and pictures to your own computer, play games, ask questions and much more, all with a click or two of the mouse.
Web sites that are primarily text-based pose few problems for people who are deaf, hard of hearing, blind or visually impaired. However, more and more sites are incorporating new technologies which use sound and moving pictures. These sites impose access barriers to users with hearing or sight disabilities. Because the Web has become such an important resource for information and services, it is vital that Web sites be designed so they are accessible to and usable by all users.
The Web Access Symbol
One of the early goals of the Web Access Project was to develop and distribute a generic, public-domain symbol which would indicate that a Web site was designed with accessibility features. NCAM solicited drawings for such a symbol from a number of designers and posted the sketches and descriptions of them on its Web site. The public was then invited to comment on the symbols-- 17 in all-- and to choose the one that best denoted accessibility. The winning symbol, designed by Stormship Studios of Boston, Massachusetts, was announced in April. It is available free of charge from NCAMÕs Web site (http://www.wgbh.org/ncam), or via anonymous FTP at 18.104.22.168. Web page designers can use the symbol to indicate that efforts have been made to accommodate the needs of deaf, hard-of-hearing, blind and visually impaired users. Extensive guidelines for designing accessible Web pages may be found at the Trace Research and Development Center's Web site (http://www.trace.wisc.edu).
To date, nearly 100 Web sites have taken advantage of the Web Access Symbol. Awareness of disabilities issues surrounding the Web has been gathering momentum, and NCAM receives several requests each week for Web site evaluations. We expect the number of sites using the symbol to continue to grow as more and more designers realize the need for accessibility. Because the symbol is available to anyone, however, NCAM is not in a position to grant permission for its use before it is placed it on a Web site. Instead, NCAM encourages Web users themselves to contact webmasters if a site which uses the symbol is not truly accessible. (NCAM also encourages Web users to contact webmasters when a site is accessible!) A list of sites using the symbol, updated approximately every two weeks, is available at the NCAM Web site.
Alt-Text Tags and Image Descriptions
As the first steps toward "earning the right" to display the symbol, webmasters are encouraged to include at least two key features on their Web sites: alt-text tags and image descriptions. These provide important navigational clues for blind users.
Many blind computer users employ a software device known as a screen reader, which reads the text shown on the screen out loud via speech synthesis. In the early days of the Internet, when most information was text-based, blind users had few problems navigating cyberspace. However, the past few years have seen a sharp increase in the use of graphics and images on the World Wide Web. Unfortunately, screen readers cannot interpret the graphic elements of a Web page; therefore, if the screen reader encounters an image or a graphic, it will usually just say something like "icon." However, it is a simple matter for a webmaster to accommodate blind users by accompanying the graphic or image with a few words. This special text is called an alt-text tag, and it identifies or describes the image or graphic. The alt-text tag for the Web Access Symbol is "Web Access Symbol (for users with disabilities)".
Since the alt-text tag identifies the image with words, the screen reader software can simply read it to the user. As a matter of fact, you don't need a screen reader to make use of alt-text tags. Anyone can see and use them, if they are part of the Web site, by programming the Web browser not to load and display images or graphics. With the images turned off, Web pages generally are displayed on your computer much faster than with the images turned on. Many sighted people with slow Internet connections browse the Web with the images turned off, as do people who just don't like to wait for images to load; like blind users, they rely on alt-text tags to tell them what an image is. Thus, if a site hasn't been designed with alt-text tags, sighted users lose out as well as blind users.
Image descriptions should also be used whenever an essential graphic or image is included on a Web page. A description summarizes a graphic in a sentence or two, providing more information than the alt-text tag. For example, the description for the Web Access Symbol is, "A globe, marked with a grid, tilts at an angle. A keyhole is cut into its surface." Descriptions can be displayed below an image, similar to a photo caption, or they can be linked to another page. Some webmasters prefer to link to descriptions to avoid cluttering up the original page. The link itself is usually the word "description" or the letter "D", and is placed next to the graphic. Clicking on the link leads the user to another page containing the description text. Once on the description page, the screen reader can read the text to the blind user. Conversely, a sighted viewer with a slow modem connection can first read the description to see if it is worthwhile to download the graphic. Once the description has been read, the user can then go back to the previous page and continue browsing the site.
Another helpful feature the webmaster can provide is a version of a Web site that omits graphics but still contains the same information found on the graphic-oriented pages. This is sometimes called a text-only alternative, or text-only page. Many sites already feature text-only pages. All information contained on the graphic pages, including the links found within the images themselves, is provided as text. A text-only alternative makes it possible for a blind user to navigate a highly graphic page but, again, also offers benefits to sighted viewers.
Image maps pose special problems for blind Web users. Since the map itself contains several different graphic links, it is important that the links be represented in text form. If a text version of the page exists, all the links found within the image map would be listed here. On the graphics page, the image-map links can be listed directly below or above the image map itself. Additionally, the alt-text tag for the image map should state that the graphic links may be accessed via the text-only page or by the links below or above.
Captioning and Audio Description on the Web
Most webmasters use graphics and photos to enhance the look of their Web pages. Some webmasters are now taking the next step by adding short movie (or video) clips to their sites. The obvious problem is that, just like any television broadcast, a movie clip with audio is inaccessible to a deaf or hard-of-hearing Web user.
Many movie clips found on the Web are created with Apple Quicktime software. These clips are composed of separate video and audio tracks. Without much difficulty, a separate text track may also be added to the clip by the webmaster. This text track can become, in effect, a caption track. In order to see the movie, the user must have special movie-player software which will retrieve the movie from the Web site and then play it back. Depending on the software, some players allow the user to turn the text track on and off, thus simulating closed captioning. If the player is not capable of turning the tracks on and off, the text track simply becomes open captions. Currently, the only movie player which allows the user to turn off the text track is MoviePlayer (version 2.1 or higher) for the Macintosh. Other players for both the Macintosh and PC will show the movie with open captions. To see several different examples of captioned movie clips, visit the NCAM Web site (http://www.wgbh.org/ncam). Detailed instructions describing how to caption movie clips have also been included at the site.
While deaf and hard-of-hearing Web users are the immediate beneficiaries of captioned movie clips, there are benefits for hearing users, too. Someone using a computer that lacks sound capability, for example, can view a captioned clip and obtain the same information as someone using a computer with sound capability. Also, captions used in conjunction with audio and video can be a valuable tool for improving reading skills of children and adults. A captioned movie's text track can also be used as a reference tool: many video players have a "search" feature which allows the user to scan the text track for a specific word or phrase, making it easy to locate a specific spot in the movie clip.
An additional useful feature of captioned movie clips is the transcript created by the captioning process. Including a transcript with the clip allows the user to read the text before deciding if it is worth taking the time to download the file. At the minimum, transcripts may be used by those who do not have any movie- playback capability, as a partial substitute for the clip itself.
Like deaf and hard-of-hearing users, blind and visually impaired Web users have problems accessing movie clips on the Web. On television, many PBS programs and a few cable programs are broadcast with audio descriptions, which describe screen action, body language and other important visual cues to viewers. These descriptions are recorded onto a third audio track of the program and are inserted into the pauses in the dialog so as not to interfere with the regular program soundtrack.
Following the premise of audio descriptions on television, NCAM recently experimented with putting audio descriptions on Web-based movie clips. Audio descriptions were recorded onto separate audio tracks of six QuickTime movies and uploaded to NCAM's Web site (http://www.wgbh.org/ncam).
The descriptions were first recorded using Macintosh-based software. Using MoviePlayer 2.5, these descriptions were then cut and pasted into the new audio track in places where there were adequate pauses in the dialog. As with captioned movie clips, the audio description track can be toggled on and off if the user is playing the clip with MoviePlayer for the Macintosh (version 2.1 or higher). Other Macintosh- based players, and all PC players which were tested, simply play the clips with open descriptions.
Movie clips are not yet found on all Web sites, but their popularity is increasing. One reason they are not widely used is that with current technology, the size of a movie clip, even a short one, can be unwieldy. A 60-second clip, for example, can contain approximately 2.5 megabytes of data-- roughly the size of a 900- page document! Using a modem with a speed of 28.8 bits per second (bps), this movie may take 20-40 minutes to download before it can even be played back. This time can increase if the download is attempted during times of heavy Internet traffic, or if the user has a slower modem (such as a 9600bps or 14.4bps). Also, the quality of movies on the Web is not ideal when compared to other forms, such as television or laser disc. New technologies, such as "streaming" video, which plays the movie directly from the server rather than downloading it to the user's computer prior to playback, can ease the time crunch and provide movies which are smaller and easier to transmit. As speed and quality improve, movie clips will undoubtedly become more common on the Web.
For more information about the Web Access Project, visit the NCAM Web site or contact Geoff Freed, CPB/WGBH National Center for Accessible Media, WGBH Educational Foundation, 125 Western Avenue, Boston, MA 02134; (617) 492-9258 (voice/TTY), (617) 782-2155 (fax), firstname.lastname@example.org (e-mail).
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