Introduction
Adobe Flash content can be viewed on nearly all computers. The Flash technology, in a general sense, may be one of the most widely available technologies used on the web. For developers, the ability to program one multimedia presentation that can be viewed the same on nearly all computers makes the technology very appealing. However, for individuals with disabilities, Flash can introduce unique accessibility problems.
Because of the multimedia nature of Flash, it can be used to deliver content through many mediums: graphics, text, video, audio, etc. Its power and flexibility give it potential to present web content in a fully accessible manner. Here are some examples of how Flash can increase accessibility:
- Multiple ways of presentation: Flash can provide content in multiple ways. View an example of multiple presentation methods (Download FLA file).
- Scalability: Because Flash is based on vector objects (mathematically defined lines and shapes) rather than raster (pixels of differing colors) technology, most Flash content can be easily scaled to any size without distortion. Individuals with low vision may be able to interact with Flash content in ways not possible with HTML content. View a scaleable example (Download FLA file).
- Keyboard accessibility: Flash allows a higher level of keyboard interaction than is allowed in HTML. Many Flash movies can be made more functional, powerful, and easy to use by allowing keyboard access. View a keyboard example (Download FLA file).
- Engaging: Flash can engage learners through interactivity, animation, sound, graphics, and many other ways. Individuals with learning or cognitive disabilities can better comprehend and focus on some Flash content. Flash multimedia can be used to supplement static HTML content.
- Self-voicing: Because of the audio capabilities of Flash, it can present content through audio, thus removing the need for a screen reader to extract audio content from the Flash movie.
Flash Accessibility Issues
Despite the ability of Flash to create highly accessible content, there are some major issues you must be aware of regarding Flash and accessibility. Nearly all of the concepts that affect HTML accessibility can also apply to Flash. These include using plenty of contrast, consistent navigation, understandable language, etc. Here are some specific strategies to make Flash accessible to different disability types:
- Hearing disabilities
- Provide synchronized captions for any audio that conveys content
- Photo epilepsy
- Remove strobing content that flashes between 2 and 55 times per second
- Motor disabilities
- Ensure the Flash content is keyboard accessible
- Do not require fine motor skills
- Cognitive disabilities
- Give users control over time sensitive content
- Provide easy to use controls and navigation schemes
- Be consistent
- Use the clearest, simplest language appropriate to the content
- Low vision
- Provide plenty of contrast
- Allow the Flash content to scale to a larger size
- Blindness
- Ensure screen reader accessibility or provide an accessible alternative
- Ensure keyboard accessibility
- Do not interfere with screen reader audio or keyboard commands
- Provide textual equivalents for all non-text elements that convey content or provide a function.
Although each of these strategies can increase accessibility, Flash content is rarely designed to include all of these strategies at the same time, thus making it inaccessible in some way. When all accessibility techniques are applied to Flash, it can be universally accessible, perhaps even more so than HTML, because the need for specific assistive technologies (with their accompanying limitations) is removed. However, such an endeavor would be difficult or even impossible with a majority of Flash content. In short, unless all of the accessibility techniques are applied, Flash may not be accessible.