Origin

 

Unlike other situations other CS-SIS members may commonly encounter, web accessibility awareness does not usually begin with a memo from a University Disability Resource Center.  Moreover, whether a given set of legal standards are applicable to any given institution are unclear and standards are inconsistently enforced. For more information about the law, refer to Assistive Technology -- Understanding the Law and the section on web accessibility.

 

The rest of this page will be devoted to voluntary efforts to make web pages accessible.  It introduces the subject and covers Guidelines 1.1 and 1.2 of the Web Content Accessibility Guidelines 2.0.

 

Identifying the Right Standard

 

Most readers (to the extent that they have heard of web accessibility at all), have heard of the Section 508 standards.  The Section 508 standards with respect to web pages are essentially a checklist of eleven items meant to address common concerns at the time the regulation was drafted.  They were expressly based on the Web Content Accessibility Guidelines 1.0 developed by W3C.  Those standards are outdated.  While a web page that meets section 508 standards would be more accessible  than one that does not, the gold standard for accessibility is WCAG 2.0.

 

Summarizing WCAG 2.0

 

WCAG 2.0 is organized by Principles, Guidelines, and Success Criteria.  The principles are general objectives and each of the four principles can be summarized in a single word: perceivable, operable, understandable, and robust.  Each of the 12 guidelines is a plain English one sentence statement of what needs to be achieved.  The 12 Success Criteria relevant to "A" level conformance and the 26 additional Success Criteria relevant to "AA" level conformance provide highly technical testable criteria by which to measure conformance.

 

Not all of the criteria are likely to apply to every page.  Some of the criteria can be conformed to with much conscious thought or effort because most webmasters/developers/content creators do certain things anyway.  Many can be conformed to with a relatively modest amount of effort.  A few require considerable time and effort.

 

The Structure of These Web Accessibility Pages

 

 The Committee will not attempt a detailed explanation of how to conform to each of the 38 Success Criteria applicable to either "A" or "AA"level conformance.  Instead, the Committee will briefly summarize each criterion in non-technical language, rate the difficulty level of achieving conformance, assess the impact of non-conformance for that criterion, discuss how to validate for that criterion (including links to web-based validators, if applicable) and provide links to detailed third-party information regarding how to conform to the criterion.

 

Principle 1 Short Title: Perceivable

 

WCAG 2.0 Principle 1

 

GUIDELINE 1.1 SHORT TITLE: TEXT ALTERNATIVES

 

WCAG 2.0 Guideline 1.1

 

Success Criteria 1.1.1 Short Title: Non-text Content

 

Summary:  Non-text content must have a textual equivalent, subject to certain exceptions.  The most relevant exception to our readers: mere decoration needs no textual equivalent.

 

Conformance Level:  A

 

Degree of Difficulty:  Low, but can be time consuming if done after the fact.

 

Consequence of Non-Conformance:  Images are effectively invisible to screen readers.  The screen reader user thus loses all image information when only part of it would be lost if conformance was maintained.

 

Validation: Can be validated with AChecker.

 

Other W3C links: How to Meet 1.1.1, Understanding 1.1.1

 

GUIDELINE 1.2 SHORT TITLE: TIME-BASED MEDIA

 

WCAG 2.0 Guideline 1.2

 

Success Criteria 1.2.1 Short Title: Audio-only and Video-only (Prerecorded)

 

Summary:  Audio-only tracks need a transcript unless the track itself is an alternative for text.  Video-only tracks either need audio description or textual description unless the track itself is an alternative for text.

 

Conformance Level:  A

 

Degree of Difficulty:  Medium, but time consuming.  Use of speech recognition software (e.g., Windows Speech Recognition) can reduce the time necessary to create a transcript if used simultaneously with audio-recording. 

 

Consequence of Non-Conformance:  Deaf individuals lose all access to audio-only tracks and blind individuals lose all access to video-only tracks.

 

Validation:  Must be validated manually.

 

Other W3C links:  How to Meet 1.2.2, Understanding 1.2.2.

 

Success Criteria 1.2.2 Short Title: Captions (Prerecorded)

 

Summary:  A video need captions unless the video itself is an alternative for text.  

 

Conformance Level:  A

 

Degree of Difficulty: Medium, but very time consuming.  Auto-captions (e.g., Google's captions for YouTube) do not in and of themselves meet this criterion.  They can be useful, however, if they can be downloaded, corrected, and re-uploaded (which is true of Google's YouTube captions).  While this is not a fast process, it is quicker than doing it from scratch and (probably) cheaper than paying a third-party.

 

Consequence of Non-Conformance:  Deaf individuals lose access to any information that is present only in the audio and cannot be discerned from the visual elements.

 

Validation:  Must be validated manually.

 

Other W3C links:  How to Meet 1.2.2, Understanding 1.2.2.

 

Success Criteria 1.2.3 Short Title: Audio Description or Media Alternative (Prerecorded)

 

Summary:  Videos need either audio description or transcripts that describe the visual elements.  Audio description refers to describing the visual elements not present in the dialogue.  There is an example of audio description for a scene from the movie Tron: Legacy in part two of Ryan Overdorf's prerecorded presentation on audio description and closed captioning for the 2011 ORALL Annual Meeting.  The audio description starts at the 4:26 mark.

 

Conformance Level:  A

 

Degree of Difficulty: High.  Audio description is probably the single most difficult task in webpage accessibility.  At conformance level A, the webpage author is permitted to do a textual equivalent instead, but this would be one of the most time-consuming tasks in Web accessibility.  Additional discussion is found under the heading for Success Criteria 1.2.5  

 

Consequence of Non-Conformance:  Visual information not present in the audio and not described or presented in screen readable text will be completely lost to the blind or low vision user.

 

Validation:  Must be validated manually.

 

Other W3C links: How to Meet 1.2.3, Understanding 1.2.3

 

Success Criteria 1.2.4 Short Title: Captions (Live)

 

Summary: Live webcasts need to be captioned.

 

Conformance Level:  AA

 

Degree of Difficulty: Impossible without using an expensive third party service.

 

Consequence of Non-Conformance:  Audio information not present visually will be completely lost to the deaf or low hearing user.

 

Validation:  Must be validated manually in real time.

 

Other W3C links:  How to Meet 1.2.4, Understanding 1.2.4

 

Success Criteria 1.2.5 Short Title: Audio Description (Prerecorded) 

 

Summary:  All videos must have audio description tracks available.

 

Conformance Level:  AA

 

Degree of Difficulty: High, in fact impossible to fulfill as stated in a "talking head" video because the presenter does not pause often enough to allow for a complete audio description track. This Success Criteria is really written with movies in mind, where there are often long pauses between dialogue. 

 

Consequence of Non-Conformance:  Visual information not present in the audio and not described will be completely lost to the blind or low vision user.

 

Validation:  Must be validated manually in real time.

 

Other W3C links: How to Meet 1.2.5, Understanding 1.2.5

 

[end part 1]

 

Assistive Technology -- Making Web Pages Accessible Part 2

SideBar