Category Archives: Accessibility

Accessibility and usability.

WCAG 2.0 Revisited

Joe Clark has kindly responded to some the many questions I raised in my last article. Specifically, he responded to the issues of validation, the baseline, multimedia; abbreviations, jargon and pronunciation, and the WCAG Samurai. I still don’t fully agree with him regarding validity, though I fully understand and accept his point of view. He has satisfactorily responded to the issues regarding multimedia and full-text alternatives, but I still have some questions about the baseline. Before I discuss these issues further, there’s just one thing I’d like to clear up.


Joe seemed to be quite offended by one small statement I made at the beginning: “… his movement against the WCAG Working Group.” As he first commented in my article and then later published on his blog, he’s not against the whole working group and I’d like to apologise for suggesting that he was.

However, I’m not sure why he was so offended by me calling his work, in particular, the WCAG Samurai, a “movement”:

I can barely get the ragtag handful of standardistas in this city together once a month for drinks, let alone run a “movement.”

I thought the WCAG Samurai seemed to fit the definition of “an organized effort by supporters of a common goal”. But regardless of that, I sincerely apologise if this is not the case.


[…] If your baseline is set too high, users will have “recourse to complain that your site is inaccessible to them.”

Sadly, no. The user has no say in the baseline designation at all.

I don’t think the user needs to have a say in the baseline designation in order to complain about inaccessibility. Regardless of what the baseline says, if a user can’t access part of the site for whatever reason, there is nothing to stop them complaining to the organisation about it (unless they can’t even access the contact information). Organisations do have some, at least moral, responsibly towards their users and/or customers to produce content that suits their, and their user’s, particular needs.

However, I’d like to get some clarification on what exactly the problem is with the baseline. Joe’s statements about it being possible to make technologies other than plain HTML, CSS and JS accessible are very well known. Such technologies include tagged PDFs and captioned/audio described videos; but all of a sudden there’s something inherently wrong with a baseline statement that says you require support for PDF or support for MPEG and SMIL.

In response to Bruce Maguire’s claims that PDF is inaccessible because:

[…] the resulting document will only be accessible to those people who have the required software and the skills to use it. […] Requiring a user to upgrade to this extent in order to read a standard document is like designing Web content presentation in such a way that most people will have to buy a new computer in order to read it. […] In any case, some of the PDAs used by blind people have no facilities for accessing PDF files”:

Joe Clark wrote:

  • It’s not like PDFs are the only item on your computer for which you require software and skills. You require both of those to surf the web and use HTML pages.
  • “PDAs used by blind people” need to be upgraded if they don’t understand PDF. Essentially, this objection boils down to “if it doesn’t work with what I’ve already got, it doesn’t work, period.” I guess time does not march on for these people. In that case, I hope you’re enjoying HTML 2.0 and your Geocities homepage.

So, I’m confused. I I understand these two points of view correctly, they seem to be conflicting:

  1. You can’t require support for some technologies (i.e. no baselines)
  2. Many technologies can be made accessible and users are just required to have appropriate software. In such cases, you don’t have to make an equivalent in another format (e.g. You don’t necessarily require an HTML alternative for PDF and so-called full-text alternatives for multimedia are apparently a joke)

Any clarification on this issue would greatly appreciated.

WCAG 2.0

In a recent controversial article on A List Apart, Joe Clark proclaimed To Hell with WCAG 2. On the surface, it seems like Joe made a strong case against the WCAG 2.0 draft in an attempt to rally support for his movement against the WCAG Working Group. Although he did raise many issues, in several cases he failed explain exactly what the problem is.

I’m fully aware of the fact that not everyone who reads Joe’s article will wade through several hundred pages from the 3 WCAG specifications, and who could blame you? I read them, but the specs are certainly long, tedious and, in many cases, extremely difficult to comprehend.

Exactly what a “page” is, let alone a “site,” will be a matter of dispute.

I somewhat agree with this. In an attempt to be technologically independent, common terms like “page” and “site” have been replaced with much more obscure technical terms like “web unit”, “authored unit” and “authored component”. Some of these terms aren’t even clearly defined or easily distinguishable from each other.

For instance, consider “authored unit” and “web unit”: two terms that have different definitions, but I still can’t quite figure out what exactly distinguishes a “set of material created as a single body by an author” from “a collection of information, consisting of one or more resources, intended to be rendered together”.

A future website that complies with WCAG 2 won’t need valid HTML—at all, ever. (More on that later.) You will, however, have to check the DOM outputs of your site in multiple browsers and prove they’re identical.

There are two issues here: whether or not validity should be required by WCAG 2.0 and the insanity of that particular technique. I’m sure everyone agrees that comparing the DOMs is an unrealistic expectation; and besides, the technique is non-normative and so it can be safely ignored.

In the current draft of the guidelines, success criterion 4.1.1 states:

Web units or authored components can be parsed unambiguously, and the relationships in the resulting data structure are also unambiguous.

How to Meet Success Criterion 4.1.1 clarifies the meaning of that a little, though it still uses rather technical lingo. It basically means that documents can be parsed properly without depending upon error recovery techniques, especially where the results are inconsistent between browsers. Strictly speaking, the wording of that success criterion doesn’t explicitly require documents to be valid; however, one of the techniques described to meet it is in fact Validating Web Units.

Personally, I’m not convinced validity should be strictly required by WCAG 2.0, I believe it should remain as just a technique. The success criteria should instead outline the purpose of validation. In other words, if you were asked: why validate? What would your answer be and how does it relate to accessibility?

As it currently stands, the working group seems to recognise that the purpose of validation is to help ensure that documents can be parsed correctly and interoperably between user agents. It’s important to realise that validation is just a technique, not a goal in itself.  It is indeed a very good technique and one that can be used to help meet the success criterion; but it is technique none-the-less.

I’m not saying validation isn’t important.  I do believe it is very important and I personally insist upon it for any site I develop, but it needs to be put into the proper context. Although I wouldn’t object to its inclusion in the guidelines, I don’t believe it needs to be enforced as a requirement on its own. If validation is to succeed in web development, it should instead succeed as part of quality assurance and best practice guidelines.

You can still use tables for layout. (And not just a table—tables for layout, plural.)

It is unfortunate the wording of these guidelines explicitly allows the use of tables for layout and does very little to discourage their use. While I believe it should be recognised that table layouts can be made relatively accessible to assistive technology, their use should still be considered a failure.

Your page, or any part of it, may blink for up to three seconds. Parts of it may not, however, “flash.”

I don’t particularly like blinking or flashing content at all, but I’m not exactly sure of the problem here. It seems to me that the guideline recognises that prolonged blinking/flashing is an accessibility issue and addresses it by limiting the time frame.

I’m no expert on the issue, nor am I aware of the use cases (beyond annoying advertisements) for allowing any blinking at all, but 3 seconds seems like a reasonable compromise to me. Is 3 seconds enough time to trigger an epileptic seizure or any other specific problems? Or is it merely an objection based on a personal dislike of blinking, rather than solid facts?

You’ll be able to define entire technologies as a “baseline,” meaning anyone without that technology has little, if any, recourse to complain that your site is inaccessible to them.

I don’t fully agree with this issue and while I do see the conceptual problem with the baseline, I don’t believe it is as bad as some people make it out to be.

There is a major difference between the statements: “This site is accessible” and “This site is accessible to users, whose UAs meet the baseline requirements”. While the latter will theoretically apply to any document conforming to WCAG 2.0, the former is a much broader statement that effectively means “This site is accessible [to everyone]”.

If your baseline is set too high, users will have “recourse to complain that your site is inaccessible to them”. The problem is that there is little guidance on specifying a realistic, accessible baseline and that means the concerns about it being set too high by organisations are indeed valid. For example, if you’re baseline includes JavaScript, anyone that chooses to disable JavaScript will be effectively denied access to the site because their UA doesn’t meet the requirements. This goes against the very principle of Unobtrusive JavaScript and I see how this is a serious problem.

On the other hand, it’s an unrealistic expectation that plain old HTML will be able to meet every possible use case and, as Joe will you tell you himself, other technologies can be made just as accessible (e.g. Accessibile PDFs).

You’ll be able to define entire directories of your site as off-limits to accessibility (including, in WCAG 2’s own example, all your freestanding videos).

I don’t see how this is a serious problem. The ability to scope a conformance statement to specific sections of the site has some very good use cases. Although failing to meet conformance for one section simply because the author doesn’t want to do so isn’t a very good excuse, the ability to scope a conformance claim is better than lying by saying the whole site is accessible.

Not that anybody ever made them accessible, but if you post videos online, you no longer have to provide audio descriptions for the blind at the lowest “conformance” level. And only prerecorded videos require captions at that level.

I’m not sure how either of these are serious issues. Those with the knowledge and tools available to provide audio descriptions of video can still do so, but requiring audio descriptions at the lowest level is an unreasonable expectation for most authors who are unlikely to have the technical skills, let alone the tools, to do so.

Such authors can still provide a full text alternative which is much easier to produce. However, Joe claimed that the full text alternative is a “discreditied holdover from WCAG 1”, yet failed to provide or link to any evidence to support that claim. His explanation stating that parts of it are not needed by the blind, and other parts by the deaf doesn’t seem to have a point – it certainly does nothing to discredit the technique.

As for requiring captions for pre-recorded videos only, I don’t understand why this is a problem at all. Would anyone seriously expect the average person with a live web cam to be able to provide captions in real time? That would require some serious effort to do, which the average author couldn’t possible do anyway. Of course it may be realistic for something like a television studio broadcasting their news online to provide captions, just as they do for TV, in which case, they can claim conformance to a higher level of accessibility.

Your podcasts may have to be remixed so that dialogue is 20 decibels louder than lengthy background noise.

That is only if authors wish to claim conformance to level 3, although I don’t understand what the problem is here. Is this an issue because the technique presents no accessibility benefits? Is it because it’s an unrealistic expectation for authors to achieve? Or is there some other reason that failed to be explained.

You can’t use offscreen positioning to add labels (e.g., to forms) that only some people, like users of assistive technology, can perceive. Everybody has to see them.

I interpret the specification differently from Joe, with regards to this issue. How to Meet Success Criterion 1.3.1 states:

The intent of this success criterion is to ensure that information and relationships that are implied by visual or auditory formatting are preserved when the presentation format changes. […] The purpose of this success criterion is to ensure that when such relationships are perceivable to one set of users, those relationships can be made to be perceivable to all.

Not everybody has to see the text labels; there is nothing there that says they can’t be hidden off screen. What I believe it is saying is that the same meaning needs to be conveyed to all users, regardless of the presentation. e.g. For a visual user, the meaning may be conveyed through the visual layout, colours, icons, etc, but for an aural user, for example, the same meaning may be conveyed by speaking the text label.

CSS layouts, particularly those with absolutely-positioned elements that are removed from the document flow, may simply be prohibited at the highest level. In fact, source order must match presentation order even at the lowest level.

Again, I interpret the spec differently. Nothing in the spec says the presentation order much match the source order, it simply states that the same meaning must be conveyed to the user regardless of the presentation. It’s ok to use absolute positioning (or any other layout method) to alter the presentational ordering, as long as the meaning of the content is not altered.

Also at the highest level, you have to provide a way to find all of the following:

  1. Definitions of idioms and “jargon”
  2. Expansion of acronyms
  3. Pronunciations of some words

Again, I don’t see how this is a problem at all. It is only required for level 3 conformance and is there any reason why providing such things would be a bad idea? Providing definitions may be as simple as linking to a glossary or dictionary entry and expansions for acronyms is as simple as using the <abbr> and <acronym> elements. Providing pronunciations of some words, where necessary, is not only useful for disabled, it’s useful for anyone that reads a difficult word they’ve never heard before and may not have an obvious pronunciation.

WCAG Samurai

Joe also announced the launch of the WCAG Samurai: an effort to publish corrections for and extensions to the existing WCAG 1.0 recommendation. In principle, it’s a very good idea for the community to begin addressing accessibility issues and the serious problems with WCAG 2.0 themselves, but my main concern with the WCAG Samurai is this:

… another thing we’re not going to do is run a totally open process. It’s a viable model for standards development, one I have championed in another context, but in web accessibility it is proven not to work.

WCAG Samurai will toil in obscurity for the foreseeable future. Membership rolls will not be published, and membership is by invitation only.

Working on this behind closed doors seems like a huge mistake to me. In fact, it seems down right hypocritical of Joe to discredit the WCAG 2.0 working group process on the grounds that it and, indeed, the results themselves are inaccessible to a wide audience; only to go ahead and make the WCAG Samurai process inaccessible to, and hidden away from, all but the few invited elite.

I’m not too concerned that participation is strictly limited to the select few, but I think there really needs to be a way for the community to at least watch from the sidelines and see everything that goes on, even if they can’t contribute directly. It has been stated that the WCAG Samurai website will soon have a news feed for updates, so there is a chance that’s exactly what we’ll get.

I will admit, however, it may be too early to pass judgement on the WCAG Samurai right now, and it’s only fair that we let them give it a shot. After all, the members are unlikely to be weighed down by absurd corporate interests, but rather have the best interests of both web developers and end users in mind. We’ll just have to wait and see.

Accessible Alternate Content

For accessibility reasons, it’s important to specify alternate content for any multimedia including images, audio, video, etc. When a text alternative is provided for an image, it should serve the same purpose as the image itself and not just describe what it looks like; and similarly for other multimedia content. However, there are some cases where it’s important to know that the alternate content is replacing an image in order to give some context, even if the user can’t actually see the image (either by choice or phyisical limitation).

For example, take a recent post from Joe Clark – a well respected accessibility consultant – entitled Kills Bugs Dead. When I read this article in my feed reader, which is configured to view plain-text only (no images), this is what I read:

Truck fender has illustrations of six green-and-yellow grasshoppers in workboots and shades striking different poses, with the last two seated and stretched out on its back

After reading that, I had no clue what he was talking about. I had no idea what truck fender he was talking about, let alone having knowledge of any grasshoppers. Once I loaded the article in my browser and saw a photograph of a truck with grasshoppers as described, it suddenly became clear: the article was about the image itself and since I didn’t know there was an image, it was read out of context and didn’t make any sense.

A few weeks later, in a recent instant messaging (IM) discussion with Charl van Niekerk, we were discussing his alternate content (or lack thereof) for an image he’d used in an article entitled The guilty one at Koeberg. As in Joe Clark’s case, Charl’s article was also about the image and when I first read it in my feed reader, this is part of what I read:

South Africans might enjoy this one. 🙂

Now we know! 🙂

In this case, not only is it important to know what the image says, it’s important to know that there is an image between those two lines because it gives some context to the other content around it. Additionally, just because the user may be viewing the content without images enabled in one environment, that doesn’t mean the user can’t see the image at all and so there should be a way for the user to access it, if desired.

To summarise, these are the requirements for a solution to this problem:

  • Make it clear that there is an image being discussed.
  • Provide suitable alternate content for where the image is not available.
  • Provide easy access to the image for the user to view.

The first issue may be easily addressed by prepending the phrase “Image:” or “Photograph of…” to the alternate content and the second point is addressed by actually providing alternate content. But the third point is a little tricker.

One way to do this is with a hyperlink, but unfortunately most images are included using the img element, which only allows plain text with no markup. In Charl’s case, he made use of the object element which has a much richer content model and allows things like hyperlinks within. His markup now looks like this (URIs modified to make the example shorter):

<object type="image/jpeg" data="homer.jpg">
  <a href=" homer.jpg" type="image/jpeg">Image: Eskom –
     Koeberg Nuclear Power Plant - Reactor Maintainance,
     Head of Maintainance: Homer J. Simpson</a>

As you can see, this now clearly addresses all three requirements. But what about the average author that uses the good old img element? One alternative is to make the image itself a hyperlink, like this:

<a href=" homer.jpg" type="image/jpeg">
  <img src="homer.jpg" alt="Image: Eskom –
     Koeberg Nuclear Power Plant - Reactor Maintainance,
     Head of Maintainance: Homer J. Simpson"></a>

Another alternative is to place a hyperlink as text after the image, like this:

<img src="homer.jpg" alt="Image: Eskom –
    Koeberg Nuclear Power Plant - Reactor Maintainance,
    Head of Maintainance: Homer J. Simpson">
<a href="homer.jpg" type="image/jpeg">(view image)</a>

There may be other, possibly more accessible, alternatives I couldn’t think of. Let me know. What do you think of these methods and how would you improve them?