- From: Steve Faulkner <faulkner.steve@gmail.com>
- Date: Wed, 4 May 2011 10:57:07 +0100
- To: Maciej Stachowiak <mjs@apple.com>, Paul Cotton <Paul.Cotton@microsoft.com>, Sam Ruby <rubys@intertwingly.net>
- Cc: HTMLWG WG <public-html@w3.org>
- Message-ID: <BANLkTik+OrBXjxZmZ-wOMzACh_QuRHLDsg@mail.gmail.com>
Hi Maciej, I am working on a proposal to re-open the decision in regards to title/alt providing clarifications and new information, so will withdraw my formal objection at this time. regards Stevef On 18 April 2011 22:28, Steve Faulkner <faulkner.steve@gmail.com> wrote: > Hi maciej, > > This is a formal objection to the decision in regards to allowing > title as conforming when alt is omitted. > > regards > Stevef > > On 18 April 2011 21:33, Maciej Stachowiak <mjs@apple.com> wrote: > > > > The decision follows. The chairs made an effort to explicitly address > > all arguments presented in the Change Proposals on this topic in > > addition to arguments posted as objections in the poll. > > > > *** Question before the Working Group *** > > > > There is a basic disagreement in the group on the validity > > requirements for alt. The result was two issues, six change > > proposals, and a straw poll for objections: > > > > http://www.w3.org/html/wg/tracker/issues/31 > > http://www.w3.org/html/wg/tracker/issues/80 > > http://lists.w3.org/Archives/Public/public-html/2010Jul/0050.html > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20090126 > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100706 > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100707 > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100510 > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100504 > > > http://www.w3.org/2002/09/wbs/40318/issue-31-80-validation-objection-poll/results > > > > Note: other aspects of these issues included other Change Proposals and > > led to separate polls. > > > > == Points in Dispute == > > > > Six separate markup features were proposed as possible exemptions to > > the general requirement to specify an alt attribute. In other words, > > for each construct, there was a proposal that it is a conforming > > replacement for alt. > > > > Each proposal had separate pro and con arguments, but the structure of > > each dispute was broadly similar: > > > > * For each construct, some argued that there is a valid use case for > > allowing this particular exemption, which cannot be satisfied in any > > other way. > > > > * In many cases, the validity of proposed use cases was disputed. It > > was argued that the use case is improper or should not be served. > > > > * In many cases, there were objections based on redundancy; it was > > claimed that other mechanisms can serve the same use cases. > > > > * Notwithstanding use cases, many objections indicated that Omitting > > alt may have negative consequences, and that tese could be worse > > than the consequences of denying a use case. > > > > These lines of argument all have some validity. However, for the > > various proposed exemptions, the balance of the arguments was affected > > by the specific details of that exemption. The Chairs made an effort > > to evaluate the arguments in a consistent way. > > > > In particular, if strong objections establish a valid, non-redundant > > use case for omitting alt in a specific case, even after accounting > > for objections based on validity or redundancy, then the bar for > > negative consequences was fairly high. The negative consequences > > claimed would have to constitute stronger objections than objections > > based on failing to serve the use case. > > > > On the other hand, if no valid use cases were established for a > > particular case of omitting alt, or if there were strong objections > > based on validity or redundancy, then the bar for negative > > consequences was fairly low. Even relatively weak objections based on > > negative consequences could prevail in such a case. > > > > Examining the individual questions: > > > > > > == Should it be permitted to omit alt when an aria-labelledby attribute > is specified? == > > > > At least one Change Proposal argued that when the aria-labeldby > > attribute is specified, it should be permitted to omit the alt > > attribute. > > > > A Change Proposal argued that aria-labelledby has a valid > > use case: > > > > For visual users an image can have an implied label due to > > proximity and placement in relation to the image. The > > aria-labelledby attribute provides a method to explicitly > > associate a text alternative with an image, like the alt > > attribute. The difference being that the text is available to all > > by default facilitating universal design. > > > > This technique would be especially useful for image galleries with > > the developer adding the aria-labelledby attribute to the > > template. Author adding a text alternative via a text field. > > > > No one disputed the need to serve these use cases. > > > > Thus, the need to serve these use cases was established as valid and > > could potentially make for a strong objection. > > > > However, one survey comment argued (paraphrasing) that it's not > > necessary to allow missing alt when aria-labelledby is also specified; > > authors already have options that satisfy these use cases. > > > > Furthermore, responses on other survey questions proposed figcaption > > to serve similar use cases. > > > > No one disputed the claims of redundancy. Thus, the arguments based on > > redundancy are a strong objection. > > > > Overall, then, while omitting alt when aria-labelledby is specified > > was found to have valid use cases, it was also found to be redundant > > with other constructs. Therefore, the bar for establishing negative > > consequences is low in this case. > > > > Attention then turns to whether there are negative consequences > > omitting alt when aria-labelledby is specified. One argument was that > > it's problematic to let ARIA affect the conformance of non-ARIA > > constructs: > > > > The aria-labelledby="" attribute should be allowed, but should not > > affect conformance criteria of non-ARIA content since ARIA is only > > an annotation mechanism for accessibility APIs. > > > > And similarly: > > > > Not having any mention of technologies from other layers, > > e.g. ARIA or RDFa, prevents layering violations and avoids abusing > > annotation technologies for core conformance. > > > > These objections lacked specifics on the harm that would be caused, so > > was relatively weak, but no one disputed them. > > > > To permit the omission of @alt because there is @aria-labelledby, > > is a permission to omit the @alt of a non-presentational image. I > > believe there should never be permission to drop @alt on any > > non-presentational image as it represents a complication of the > > rules that authors have to cope with... > > > > This objection is moderate in strength. Complexity is a valid > > objection to features that have no valid, unique use cases. > > > > Although the objections based on negative consequences ranged from > > relatively weak to moderately strong, aria-labelledby was established > > to be redundant, and so the bar for negative consequences was low. > > > > Therefore, on balance, the proposal to still require alt when > > aria-labelledby is specified drew weaker objections, compared to the > > proposal to allow alt to be omitted when aria-labelledby is > > present. Specific problems of varying severity were identified. > > Combined with the fact that omitting alt when aria-labelledby is > > specified was found to be redundant for its use cases, this > > constitutes a strong objection. > > > > > > == Should it be permitted to omit alt when role=presentation is > specified? == > > > > At least one Change Proposal argued that when the role attribute is > > specified with a value of "presentation", it should be permitted to omit > > the alt attribute. > > > > The case for allowing role=presentation to replace alt was relatively > > limited: > > > > Why allow role="presentation" to act as an alternative to alt="" ? > > > > It is specified and implemented to do what alt="" is specified to > > do. It is non specific, it works on all elements. As per the > > rules specified in current spec pertaining to its use [24], the > > use of role="presentation" is not dis-allowed on the img element > > it is in fact stated that it is the only role that can be applied > > to an img that has an alt=""... > > > > This was the only argument presented, and it does not seem to state a > > use case that specifically requires role=presentation instead of alt > > with an empty value. It argues that the role=presentation exemption > > *could* be allowed, but it doesn't make the case that it *should* be > > allowed, or that there is any problem caused by disallowing. Thus, > > this was taken to be a weak objection. > > > > Since no effective case was made that omitting alt when > > role=presentation is specified has a non-redundant, valid use case, > > the bar for establishing negative consequences was extremely low. > > > > A number of Change Proposal and survey comments objected to allowing > > alt to be left off when role=presentation is specified. One comment > > argued that this state is self-contradictory: > > > > I object to allowing role="presentation" to be specified without > > an alt="" attribute because it would allow a state that is > > contradictory. Making a page self-contradictory is an authoring > > mistake. Authoring conformance criteria should help authors catch > > mistakes. > > > > This objection was moderately weak, as it lacks detail. Why is it > > self-contradictory to allow role="presentation" without an alt="" > > attribute, but apparently not self-contradictory to allow alt="" > > without role="presentation"? On the other hand, no one disputed this > > argument. > > > > Another comment objected to the role=presentation exemption on the > > basis of simplicity: > > > > We should have a simple rule that img role requires a empty @alt > > when the role is presentational, regardless of whether the > > presentational role is explicit or implicit. > > > > And another objection along similar lines also argued for a simpler > > rule: > > > > By permitting role=presentation as a full replacement for the empty > > alt, we - for no good reason - takes away the focus on correct use > > of @alt, and this - in a situation where @role can *help authors* > > to use @alt as intended. By insisting that there must be an empty > > alt even when there is a role=presentation, we are consequent with > > regard to what has been the rule until now. We are stable. > > > > These objections are moderate in strength. Complexity is a valid > > objection to features that have no valid, unique use cases. > > > > Another objection (framed as a positive effect for a different > > proposal) made a point related to simplicity, namely that ARIA should > > not affect the non-ARIA validation rules: > > > > Not having any mention of technologies from other layers, > > e.g. ARIA or RDFa, prevents layering violations and avoids abusing > > annotation technologies for core conformance. > > > > This was taken to be a weak objection in itself, since it presents no > > details of the claimed layering violations or abuse. However, the > > following comment provides more detail on the problems that could be > > created by such layering violations: > > > > Lack of @alt in combination with role=presentation, in general > > poses no issue to sighted users, unless the @src URL is rotten or > > image display is not supported or temporarily disabled (during page > > load). In that case, then user agents generates replacement text > > such as [image] for the lacking alt. Sighted users are able to > > live with this, although they may perceive the image to be an > > important one rather than a presentational one, and if there are > > many, it disturbs. Users may see the @alt text while the page > > loads etc. Should validation ignore such issues? I don't think > > so. By setting the role to "presentation", these problems are > > hidden from users of ARIA supporting AT. And this fine. However > > validators should help authors. More precisely they should help > > them to care for also those user groups that are disturbed by the > > lack of empty @alt on presentational images and also to avoid > > visual annoyance that they themselves may care for. And it should > > help authors to author consequent markup. And should therefore > > complain about the lack of an empty @alt for images with > > role=presentation. > > > > This is a moderately strong objection. It provides specific examples > > of the problems that could be created by specifying role=presentation > > without explicitly specifying empty alt="". This is somewhat weakened > > by the fact that these problems are mostly minor and only affect edge > > cases. > > > > Yet another objection argues: > > > > Consider a GUI authoring tool used by end-users, not professional > > Web developers or content authors. Such tools generate <img> > > elements, but it is not always appropriate for such tools to pause > > and demand alt text from the user before continuing. Expecting > > such a tool to generate role=presentation instead of its current > > behavior (generating no alt attribute) results in unnecessarily > > verbose markup for no additional benefit. > > > > This objection seems somewhat tangential to the point, but is taken as > > weak supporting evidence that there is not a strong use case for > > role=presentation without alt being specified. > > > > Although the objections based on negative consequences ranged from > > weak to only moderately strong, omitting alt when role=presentation is > > specified was not found to have any valid, non-redundant use cases, > > and so the bar for negative consequences was extremely low. > > > > > > Overall, the proposal to still require alt when role=presentation is > > specified drew weaker objections, compared to the proposal to allow > > alt to be omitted when role=presentation is present. Specific problems > > of varying severity were identified. Combined with the fact that there > > was no clearly identified use case that specifically required use of > > role=presentation without alt, this constitutes an overall strong > > objection. > > > > > > == Should it be permitted to omit alt when the generator mechanism is > present? == > > > > At least one Change Proposal argued that when a page is created by an > > automated content generation tool, and that tool indicates this using > > <meta name=generator>, it should be permitted to omit the alt > > attribute. > > > > It was argued that there was a valid use case for the generator > > exemption, namely automated content generators which cannot produce > > alt themselves and for various reasons cannot or will not demand alt > > from the user. The following objection, though entered for > > role=presentation, directly argues one such use case: > > > > Consider a GUI authoring tool used by end-users, not professional > > Web developers or content authors. Such tools generate <img> > > elements, but it is not always appropriate for such tools to pause > > and demand alt text from the user before continuing. > > > > Several objectors cited this use case, and further pointed out that if > > content generators are forced to generate nonconforming markup to > > satisfy this use case, they may instead enter bogus alt values, which > > would merely exacerbate the problem: > > > > If an authoring tool or other generator does not have sufficient > > information to include either alternative text or a caption, there > > is nothing the tool can do. If we say that in those cases the > > authoring tool would be non-conforming if it didn't provide > > alternative text or a caption, then the tool will just provide > > bogus (placebo) alt="" attribute values, which just makes the > > problem non-machine-detectable instead. To address this, > > therefore, we should allow generator tools to include images > > without alternative text or captions if absolutely necessary. > > > > Also: > > > > I object to treating the absence of the alt attribute as a > > validation error when the generator mechanism is used, because if > > it is treated as an error in that case, generator developers are > > incented to generate bogus values in order to make their products > > emit markup that doesn't trigger errors. (There are always > > generator developers who want to make the output of their programs > > validate.) > > > > The use case of GUI tools that do not prompt for alt seems well > > established. > > > > Some disputed the validity of the use case. For example, it was argued > > that: > > > > Application developers should follow ATAG > http://www.w3.org/TR/ATAG20/ > > > > However, it's clear that there are tools which do not follow ATAG in > > this respect, and no evidence was provided that this would change. > > > > A more detailed form of this argument was also made: > > > > When an authoring tool doesn't have anything useful to put in for > > the alt text, the tool shouldn't put anything in. A good authoring > > tool will check for missing alt text and offer to assist the user > > in repairing the content. If an author is adamant they're not > > going to provide alt text, there is no requirement that says the > > authoring tool should provide it in place of the author. In fact, > > it's just the opposite, as the authoring tool could not possibly > > know the author's intent. In this scenario, the authoring tool > > should not include the alt attribute at all, and the resulting > > markup should be considered invalid. It should be considered > > invalid because it is inaccessible, and not perceivable by some > > people. If the tool allows alt text to be provided, then the tool > > would be considered compliant (on this particular issue), even > > though the resulting markup would not be compliant, as the user > > chose not to make the content compliant. > > > > This argument is based on what tools *should* do, but in practice > > often don't. Since no evidence was provided that common practice is > > changing, this was taken to be a weak objection. > > > > Another commenter makes the case more explicitly: > > > > Unfortunately, despite what the specification says, users will > > consider an authoring tool non-conforming (buggy) if the documents > > it outputs are not flagged as conforming by validators. Therefore > > we need a way for validators and authoring tools to coordinate so > > that validators will not criticise conforming authoring tools when > > a problem (in this case missing alternative text) is the user's > > fault and not the author tool's. The simplest solution here is to > > reuse the existing document-wide flag that indicates that a > > document was created by an authoring tool, and have conformance > > checkers silently ignore the missing alternative text in that > > situation (or at least phrase the error in a way to indicate that > > the authoring tool is not to blame). > > > > Once again, this argument didn't give specific examples of the claimed > > bad incentive, so it was relatively weak. It is noteworthy however > > that several respondents took this incentive structure as a given, and > > none denied that it exists. > > > > After considering all these arguments, it seems established that there > > is a valid use case for allowing the alt attribute to be omitted when > > the generator mechanism is specified. This use case makes for a > > moderately strong objection. However, the claim of negative > > consequences to disallowing this use case was somewhat weakened by the > > lack of concrete evidence that bogus values have been used in the past > > or would be used in the future. So overall, this makes for a medium > > objection. > > > > Some of the objections based on validity could also, in theory, be > > interpreted as objections based on redundancy. In particular, arguing > > that authoring tools should just generate invalid content seems to > > argue that producing invalid content is sufficient to address the use > > case. However, since the question is one of conformance for authors > > and authoring tools, generating invalid markup does not seem to be a > > full alternative solution to the use case. > > > > Related to redundancy, it was also argued that if alt may be omitted > > when the generator mechanism is used, then the email and private > > communication exemption would be rendered largely redundant. In fact, > > this was the strongest objection to the email and private > > communications exception. As a result, accepting the generator > > exemption would allow us to reject another exemption. This constitutes > > an additional moderately strong objection. > > > > Thus, overall, the objection based on use cases for the generator > > mechanism was taken to be a medium objection. It's validity was > > disputed, but these objections were outweighed by those that argued > > for its validity. It's non-redundancy was also disputed, but such > > objections were found to be weak. Thus, overall, the bar for > > establishing negative consequences is intermediate between high and low. > > > > Some argued that omitting alt and using the generator mechanism had > > harmful consequences: > > > > Hence, the generator mechanism should not have any bearing on the > > @alt requirements as the generator string/mechanism has no bearing > > on the attributes of the <img> or the context in which the img > > appears in. The negative effects of omission of an empty or > > non-empty @alt are in no way made up for by the presence of the > > generator mechanism. > > > > This statement in itself lacks specifics, but there were some concrete > > arguments supporting the case for negative consequences: > > > > The generator mechanism facilitates the creation of inaccessible > > content. > > > > No evidence was provided that more inaccessible content would be > > created if the generator exemption is allowed than otherwise. So this > > was taken to be a weak objection. > > > > A list was provided of example <meta generator> values, and from this > > a conclusion was drawn that a tremendous amount of Web content would > > make use of the generator exemption. However, it's not clear where > > this list came from. It is not present in the spec, and does not seem > > to align with the spec's definition of a content generator. In > > particular, it includes many text editors which do not seem to qualify > > as automated markup generators. Was this list derived from the output > > of actual authoring tools? Was it found by looking at real Web > > content? In the absence of information about where this list came > > from, it was taken to have no evidentiary value. > > > > Another objection was based on the possibility of authoring mistakes: > > > > The generator mechanism is actively harmful to accessibility. If > > the generator option is left at document level, it would be far > > too easy for authors to have the software automatically insert > > "generator" and then forget to provide any text alternatives for > > images. > > > > If supported by concrete evidence, this would have been a strong > > objection. This seems like a plausible authoring mistake which would > > have negative consequences. But it was weakened by lack of any > > specific evidence that this problem has actually occurred in > > practice. This provision has been in HTML WG Editor's Drafts and > > Working Drafts since September 3, 2009: > > > > http://dev.w3.org/cvsweb/html5/spec/Overview.html?rev=1.2915 > > > > This should be enough time to see at least anecdotal evidence of the > > claimed problem. Even though normally lack of supporting evidence > > would render an objection weak, in this case, there is a > > plausible-sounding argument even in the absence of evidence, so the > > objection based on authoring mistakes is overall taken as moderately > > weak. > > > > Yet another objection was based on standards and guidelines: > > > > The generator mechanism breaks standards and guidelines requiring > > text equivalents on an individual element basis. > > > > Many specific standards and guidelines were listed. However, these > > guidelines were generally created before the generator mechanism > > exemption was invented, so it's not clear if the disagreement > > indicates a problem, or just failure to update. Thus, this was taken > > to be a weak objection. > > > > Another objection was that the generator exemption breaks the > > structure of the img element: > > > > Requiring a set of programmatically determinable valid options > > helps ensure that images have complete structure. Complete > > structure of the <img> element requires both src and text > > alternatives. > > > > This claim seems to be based on a circular argument. Omitting alt > > should not be allowed, because that would make the img element have > > incomplete structure, because img requires alt. Thus, the objection > > fails to make its case and was given no weight. > > > > Another objection argues that the generator mechanism fails to have > > certain benefits: > > > > The generator mechanism does not improve user experience or the > > chances of accessible content being produced. It does not help > > authors catch mistakes. It does not help educate developers. > > > > No one disputed this argument; but conversely, no one argued that > > generator has these benefits or should be allowed because of such > > benefits. With no concrete argument as to why the generator exception > > ought to have these benefits, this was taken to be a weak objection. > > > > An argument was made that the sole benefit of the generator mechanism > > exemption would be one that may not be desirable: > > > > The only benefit is that most tool vendors will automatically > > adhere to HTML5, as very few adhere to existing standards. The > > exception is a way to codify and bless bad tools. > > > > No evidence was provided that the other claimed benefits > > (e.g. avoiding the creation of perverse incentives to include bogus > > alt) would not materialize, thus, this claim based on "the only > > benefit" was taken as a weak objection. > > > > A further objection based on the blind photographer use case was > > entered; however, that use case was not claimed for this particular > > mechanism. That objection was instead applied to mechanisms where it > > is relevant (title and figcaption), and was given no weight for this > > question. > > > > Overall, there were many claimed disadvantages that flow from the > > generator exception, ranging from weak to moderately weak. They were > > generally unsupported by details or concrete evidence. Even though the > > use case for omitting alt when the generator mechanism is used was > > disputed and only found to be a medium objection, it still outweighs > > these claimed disadvantages, as they were all found to be weak or > > moderately weak. > > > > Thus, on the whole, the proposal to allow alt to be omitted when the > > generator mechanism is used was found to draw weaker objections, > > compared to the proposal to still require alt, even when the generator > > mechanism is used. > > > > > > == Should it be permitted to omit alt in email or other private > communications? == > > > > At least one Change Proposal argued that when content comprises email > > or other private communications, it should be permitted to omit the > > alt attribute. > > > > The use case was expounded at some length, giving the example of a > > complex image in private e-mail: > > > > 3. PRIVATE USE: In some cases, extremely complex images may be > > sent from one user to another as part of a private HTML document > > or HTML e-mail. Such images may be so complex that writing useful > > alternative text would be a significant endeavour of its own, > > tantamount to recasting the entire image as text. Ordinarily, that > > work would be worth the effort, since not all users are able to > > see the images; the specification should in fact require that work > > ordinarily. However, we would be ignored (and likely ridiculed) if > > we required people to write such text in the case of private HTML > > documents or HTML e-mails amongst users who know each other and > > are aware of each other's abilities (both technical and physical) > > to access visual images. Therefore we should have an exception in > > the requirements for this specific case. ... > > > > Now, we do not want conformance checkers to "allow" anyone to omit > > alternative text just in case they are in this situation, so we > > should further constrain conformance checkers to not allow this > > unless they have been specifically configured. If we fail to do > > this, we would undermine the entire attempt at making pages more > > accessible by requiring alternative text for images in the normal > > case. > > > > Furthering this argument, it was claimed that alt is often unnecessary > > in private communications, and would be omitted anyway, and therefore > > the spec should not make a requirement that would not be followed: > > > > It makes no sense to require an author to provide content in two > > forms (image and text) when one of those forms can be handled by > > the entire target audience for the content. (A requirement > > requiring that one's wife write a description of every photo sent > > to one's husband is just going to be ignored, so there's no point > > having such a requirement.) > > > > Others argued that, since people engaged in private communication > > would disregard the alt requirement anyway, no provision needs to be > > made for it: > > > > Private situation does not need to be mentioned in the spec, just > > as copyright licenses typically do not mention what the user is > > authorized by law to do in private with the said thing. Man and > > wife do not validate before they communicate with each others. It > > improves nothing to put this particular exception in the spec - in > > instead creates an *artificial* permission which really doesn't > > permit anything: It is similar to adding restrictions or rights > > which the copyright holder nevertheless cannot whether permit or > > restrict this right. > > > > Similarly: > > > > It is an author's prerogative not to provide text alternatives for > > images because they're writing for themselves, close friends or > > relatives. However, a HTML <img> element without both src and text > > alternative is still not complete. Therefore, it should not be > > considered valid. > > > > These were taken to be an objections based on validity or redundancy > > (it's not clear which was intended). Arguing that something should be > > allowed because people will do it anyway seems like a marginally > > stronger objection than arguing that something need not be allowed > > because people will disregard the spec. The set of valid use cases has > > generally been taken to be a strong influence on what markup should be > > conforming. > > > > For one specific form of the use case, specifically the case where a > > complex image requires a long description, validity was was disputed: > > > > Regarding Proposal 1's statement about a complex image use case in > > an email, it is not applicable. ISSUE 31- missing alt is about > > short text alternatives not long ones. No one expects a long > > description for alt text. In fact that would be incorrect. Complex > > images would be covered by ISSUE 30- Longdesc. > > > > Since longdesc is not currently allowed, per WG decision, this does > > not seem like a relevant objection. Further, complex images requiring > > long descriptions were not the only use case cited. So this was taken > > to be a weak objection. > > > > Examining the question of redundancy, one commenter wrote: > > > > Consider the same sort of GUI authoring tool I described above, > > [..] For such tools, this option is essentially redundant with the > > generator exception option. If both of these exceptions were > > allowed, we would prefer tools to use the generator > > mechanism. That leaves the use case of hand-authored content in > > private communication, which doesn't seem common enough for the > > spec to explicitly address. > > > > This objection argues that the private communication exemption is > > largely redundant if the generator exemption is allowed. > > > > Looking into the matter deeper, no one specifically claimed a personal > > interest in hand-authoring private communications in HTML format > > without specifying alt. Nor did anyone claim interest in implementing > > a validator feature to implement a special "private communications" > > mode. This strengthens the claim that the true core of the use case is > > covered by the generator exception. > > > > Thus, while the private communication exception was established to > > have a valid use case via marginally strong objections, this was > > greatly weakened by the objection that most of the use case, and > > perhaps nearly all in practice, is sufficiently well served by another > > mechanism. Therefore, the bar for objections based on negative > > consequences was low. > > > > On the topic of harm following from this exception, somer argued that > > senders or recipients of private communication may derive ancillary > > benefits from including alt: > > > > And it is not a future proof rule: users keep e-mail archives for > > years. One never knows: after agreeing to not include an alt, the > > receiver may turn blind, he/she may unexpectedly be hindered from > > using a graphical e-mail program and the sender himself/herself > > may loose the image (because the program allows to delete > > attachments) etc. > > > > And similarly: > > > > Sighted recipients. They: May have a slow connection and turn off > > images to speed download. May have an expensive data roaming > > connection (that is not slow). May have images turned off to > > decrease bandwidth use in order to lower their Internet usage > > fees. May have a text-only user agent. May be listening to the > > page being read out by a voice browser or other voice output, for > > example, as they drive or otherwise cannot read the web page. > > > > This was taken to be a moderately weak objection, since the writers of > > this objections also claimed that people could disregard the rule in > > private communication, even if it made their content > > non-conforming. This undermines the premise that these benefits are so > > compelling, that senders of private emails must be required to specify > > alt. However, this was not as weak as some other objections, since > > specifics were provided. > > > > Others argued that allowing this exemption would encourage seeking of > > loopholes: > > > > Further more, it encourages authors to look for loopholes. > > > > This was taken to be weak, because no specifics were provided. > > > > It was also claimed that the private communication exception > > discriminates: > > > > The email exception spec text profiles, targets, and discriminates > > between people on the basis of ability or disability. > > > > However, no specific evidence was given that this provision is > > discriminatory. So this was taken to be a weak objection. > > > > Another objection was on the basis of structural integrity. > > > > The email exception mechanism breaks the structural integrity of > > the <img> element. > > > > This linked the same argument as for the generator exemption, that > > omitting alt breaks structural integrity because alt is required. Once > > again, it was given no weight. > > > > The objections to allowing alt to be omitted in private communications > > based on negative consequences ranged from weak to moderately > > weak. However, because the omitting alt in this case was identified as > > redundant, the bar for claims of negative consequences was low. Even > > moderately weak objections are sufficient. > > > > Thus, overall, the proposal to require alt even in private communications > > and email (if none of the other exemptions applies) was found to draw > > weaker objections than the proposal to allow alt to be omitted in all > > cases in private communications. > > > > > > == Should it be permitted to omit alt when the title attribute is > specified? == > > > > At least one Change Proposal argued that when an image has a title > > attribute specified, it should be permitted to omit the alt attribute. > > > > Change proposals and poll responses argued that there are valid use > > cases for the title exemption. One use case proposed is that of > > content authors who cannot provide a true textual equivalent, but can > > provide a caption; one specific example was blind photographers: > > > > If an author is unable to include alternative text (e.g. they are > > a blind photographer), then they should still be required to > > include _some_ information, which could include the image's > > caption. The caption belongs in the title="" attribute or in > > <figcaption>. > > > > And similarly: > > > > 2. EQUALITY: There are certain edge cases where a page producer > > must reference an image without knowing what the image is. Such a > > producer cannot, by definition, provide a textual alternative to > > the image: they do not know what the image is. > > > > One example of this would be a blind photographer who has taken a > > hundred photos during a vacation, without keeping track of any > > information as to when or where each photo was taken. Faced with > > these one hundred JPEG images and the desire to write an HTML Web > > page that exposes those images, the photographer has no ability to > > provide alternative text. > > > > This seems like a strong objection to dropping both the title and > > figcaption exemptions; though it does not clearly establish that both > > need to be allowed. > > > > An opposed objection argues that this use case is redundant, because > > it is satisfied by blind photographers or others in this situation > > creating nonconforming content: > > > > The blind photographer use case in Proposal 1 is a red herring. A > > blind photographer is not prohibited from publishing photos > > without text alternatives. They are perfectly free to do so. But > > no matter if a photographer is sighted or not, if that > > photographer does not provide a text alternative for an <img> > > element, it doesn't change two facts: > > * The <img> element is still incomplete. > > * A blind USER cannot perceive a photo without a text alternative, > > even if a blind photographer takes it. > > > > It is true that there are constructs in HTML5 that "work" (in the > > sense that they have a particular effect), even though they are not > > "conforming". However, in general, the rules for content conformance > > have been treated in decisions as being driven largely by the set of > > valid use cases for authors. The argument that authors could simply > > create nonconforming content appears to concede the validity of the > > use case and was thus taken as a weak objection. > > > > A further claimed use case was distinguishing advisory information > > from textual equivalents: > > > > Advisory information (what title="" contains) is generally > > different from textual equivalents (what alt="" contains). That > > said, user agents could expose such content to the A11Y layer in > > such cases, and this is clearly better than not exposing such > > content. As such, we support permitting such markup. > > > > Since this lacked specific examples of when such a distinction is > > needed, it was taken to be a relatively weak objection. However, this > > objection was not seriously disputed. A comment apparently in > > opposition to allowing title said: > > > > Authors are advised to only use the title attribute for "additional > > information" and not as a full equivalent alternative. > > > > Yet this only seems to reinforce the premise that there is a > > distinction between the two, and thus was taken as an even weaker > > objection. > > > > There were no further objections to validity of these use cases. > > > > One might wonder: since the use cases for omitting alt when title is > > specified are described as being served by either title or figcaption, > > is it necessary to allow omitting alt in both cases, or only for one > > of these constructs? However, both advocates and opponents of these > > mechanisms pointed out important and relevant differences in > > behavior. In any case, no objection was made on the grounds of > > redundancy between these features. Nor was any specific reason given > > to pick one or the other. Thus, the use cases for title were not found > > to be redundant. > > > > On the whole then, strong objections establish that omitting alt when > > title is specified has valid, non-redundant use cases. Therefore, the > > bar for objections based on negative consequences is high. > > > > Examining the claims of negative consequences, some argued that > > allowing alt to be omitted when title is title specified is > > problematic, because the title attribute is fundamentally not > > accessible: > > > > The title attribute is not an acceptable text alternative as it's > > content is not displayed to the user unless they can use a mouse > > and beforehand know the content is there. The content of the image > > title attribute is also often not detected by AT by default unless > > the user makes an explicit choice in their preferences to announce > > the attribute contents. > > > > Similarly: > > > > To reflect the unsuitability of title attribute content to act as > > a caption when a text alternative is not available, as the content > > is not displayed to the user unless they can use a mouse and they > > know the content is there. Refer to Issue 80 for more detail. > > > > And furthermore: > > > > The title attribute has been around for over 10 years and it has > > never been implemented in a way that would make it a suitable > > substitute for alt attribute content, and there is no sign from > > implementors that this situation will change. > > > > Also: > > > > The specification forbids user agents from displaying title > > attribute content in the same way it displays alt attribute > > content: "The alt attribute does not represent advisory > > information. User agents must not present the contents of the alt > > attribute in the same way as content of the title attribute." > > > > This constraint makes it even less likely that at some point in > > the future a critical mass of browsers will implement title > > attribute such that its content will be displayed in a manner that > > provides equivalent access to the content for all users. > > > > Though somewhat tricky to follow, the following passage implies that in > at least some > > assistive technologies, the contents of the title attribute *are* > > exposed, in an accessible way: > > > > What we *should* avoid is the the situation we have in the W3 > > HTML4 validation service today: there it is permitted to combine > > empty @alt with a non-empty @title: <img src=img alt="" > > title="Lorem ipsum." > VoiceOver, in accordance with my Validity > > map, treats this example as non-presentational. And, again in > > accordance with my Validity map, the @alt should therefore at > > contain an @alt, since the @alt should reflect the role of the > > <img>. Note that VoiceOver makes no big difference between > > @alt="<empty>" and no alt at all. Thus, as far as VoiceOVer is > > concerned, the need for a non-empty @alt should not only be seen > > as an accessibility but just as much as a simple rule for authors > > to follow! > > > > This was combined with a second-hand report, lacking specifics, that > > other assistive technology products would not do so: > > > > However, reportedly, in other AT than VoiceOver, the lack of @alt > > in an <img> which has a non-empty @title, creates more or less the > > same problems whether or not @title is lacking, even if some very > > (conscious) AT user may get help from @title if they enable > > support for it. This is an *accessibility* reason to require an > > @alt even if the <img> has a @title. > > > > Since at least one product is known from testing to expose title="" in > > an accessible way, and since no evidence was provided that other > > products cannot or will not do so, the objection that title is an > > inaccessible mechanism was taken to be a weak objection. The claim > > that it can't or won't be exposed in an accessible way is outweighed > > by the concrete example of it being exposed in an accessible way. > > > > A more subtle objection was the claim that, since many products do not > > yet expose title in an accessible way, that it is problematic to use > > it now: > > > > Encouraging use of the title attribute before it is implemented in > > an accessible way does a disservice to users with disabilities. > > > > Not much evidence was provided that this cannot or will not change, > > however. At least one product is already known to expose title in an > > accessible way, and others were reported to do so as an option. Thus, > > this was also taken as a weak objection. > > > > Another argument claims that authors may simply specify title and then > > neglect to specify alt, even if a proper text alternative *is* known: > > > > Suggesting that the title is an adequate substitute may encourage > > authors to not provide a text alternative using the alt attribute > > as conformance checkers will not flag the absence of the alt > > attribute as an issue. > > > > No specific evidence was presented that this would occur, so this was > > taken to be a weak objection. > > > > Another objection argued: > > > > Also, an empty @alt should together with a non-empty @atitle should > > count as *invalid* since the sighted would perceive such an image > > as non-presentational. > > > > However, this objection failed to explain why the situation described > > would be a problem, so it was taken to be weak. > > > > Thus, overall, the objections based on problems created by omitting > > alt when title is specified were found to be weak. But omitting alt > > when title is specified was found to serve valid, non-redundant use > > cases. > > > > Thus, overall, the proposal to allow alt to be omitted when title is > > specified was found to draw weaker objections than the proposal to > > still require alt when title is specified. > > > > > > == Should it be permitted to omit alt when the image is in a figure with > a figcaption? == > > > > At least one Change Proposal argued that when an image is inside a > > figure element with a figcaption specified, it should be permitted to > > omit the alt attribute. > > > > The same use cases were claimed for the figcaption exemption as for > > the title exemption. For brevity we do not repeat them here, but we > > note that overall they were found to constitute strong objections. > > > > It might be argued that this makes figcaption and title redundant > > mechanisms, however, both advocates and opponents of these mechanisms > > pointed out important and relevant differences in behavior. In any > > case, no objection was made on the grounds of redundancy between these > > features. > > > > Thus, as with title, omitting alt when a figcaption is used was found > > to have valid, non-redundant use cases. Thus, the bar for claims of > > negative consequences was high > > > > One claimed problem with allowing the figcaption exemption was the > > figure/figcaption association is not present in current assistive > > technology products: > > > > ... based on today's user agents and AT this is a relationship > > that is unsupported by AT. We should define this use case, and > > thus allow AT to use <figcaption> as a label for the image. > > > > However, this lacked specifics on what products were tested. No > > evidence was provided that such products would not support the > > relatively new figcaption feature in the future. And it concedes that > > the use case is valid. Thus, this was taken to be a weak objection. > > > > Another argument claims that that some placeholder alt value could be > > included when figcaption provides a caption: > > > > There is little reason to permit the dropping of the @alt when > > there is a figcaption. The author can just as well identify the > > image with a short text such "photo" or "figure", "diagram" or - > > even - whitespace inside the @alt as this has the same effect and > > is fast and quick for the author (but whitespace would probably > > make it invisible to text browsers so this is no good advice - > > though, not everyone obeys this but treat it as no-alt and > > generates an @alt text.). Since user agents may repair the lack of > > @alt if the author doesn't add it, and this yet another reason for > > the same. It is nice and well if the figcaption provides a > > label/caption for the image. However, it is a complicating rule to > > say that one may drop the @alt. > > > > This argument claims that alt could be provided anyway, even if the > > primary text to expose is a caption in figcaption. However, no > > argument is given for why the particular examples chosen (e.g. alt > > containing only whitespace) are superior to omitting alt and relying > > on the caption. In fact, one respondent claimed that such a > > requirement would be excessive: > > > > I object to requiring the presence of the alt attribute when the > > image is in a figure with figcaption, because excessive > > requirements will be perceived to lower the seriousness of all > > requirements and requiring information that authors are likely to > > consider duplicate information is likely to be perceived as an > > excessive requirement. > > > > This was found to be a stronger objection than the objection that the > > figcaption exception is unnecessary. > > > > Another objection raised the possibility of multiple images in a > > single figcaption: > > > > One thing to consider, as well, is that we are likely to see many > > instances when there is more than the image inside the figure - > > perhaps there is some text there, or two images. What then? > > Authors are likely to not discern between the one image use case > > and more-than-just-an-image use case very well. (May be it also > > isn't necessary to discern so much - but this remains to be > > tested.) > > > > No evidence was provided that multiple images in a single figure has > > created a problem in practice, so this was taken to be a weak > > objection. > > > > Another respondent argued that figcaption was a sufficient replacement > > for alt: > > > > I do not object to the figcaption being permitted without an alt > > attribute, as it can act as a mechanism to associate a text > > alternative with an image when the text is appropriate to be > > viewed in conjunction with the display of the image or when an > > text alternative has not yet been provided via the alt attribute. > > > > However, this comment does not seem to comprise an objection either > > way, so it was given no weight. > > > > All objections based on negative consequences of allowing alt to be > > omitted when figcaption is used were found to be weak. The bar > > established by use cases was high. > > > > Therefore, in summary, the proposal to allow alt to be omitted on > > images inside a <figure> element with a <figcaption> drew weaker > > objections, compared to the proposal to still require alt in this > > case. There was no objection to the claim that figcaption has valid > > use cases, and little or no specific harm was identified. > > > > *** Decision of the Working Group *** > > > > Therefore, the HTML Working Group hereby decides that: > > > > * The presence of aria-labelledby does not make missing alt conforming. > > * The presence of role=presentation does not make missing alt > conforming. > > * The presence of <meta name=generator> makes missing alt conforming. > > * Use of private communications does not, in itself, make missing alt > conforming. > > * The presence of title makes missing alt conforming. > > * The presence of figcaption makes missing alt conforming. > > > > The two Change Proposals closest to these results are those identified > > as Requirement Set 1 and Requirement Set 4: > > > > http://lists.w3.org/Archives/Public/public-html/2010Jul/0050.html > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100707 > > > > These Change Proposals agree with each other and with the WG decision > > on aria-labeldby, role=presentation and figcaption. > > > > On the generator mechanism and the title attribute, Requirement Set 1 > > aligns with the WG decision: > > > > http://lists.w3.org/Archives/Public/public-html/2010Jul/0050.html > > > > On the email exception, Requirement Set 4 aligns with the WG decision: > > > > http://www.w3.org/html/wg/wiki/ChangeProposals/ImgElement20100707 > > > > Thus, overall, the WG adopts the Requirement Set 1 proposal with > > regards to aria-labelledby, role=presentation, <meta name=generator>, > > title and figcaption; but Requirement Set 4 with regards to the email > > exception. > > > > == Next Steps == > > > > Bug 8646 is to be REOPENED and marked as WGDecision. > > > > Since the combination of prevailing Change Proposals does call for a > > spec change, the editor is hereby directed to make the changes in > > accordance with the Decision of the Working Group above. Once those > > changes, as well as changes for the other surveys on these issues, are > > complete, ISSUE-31 and ISSUE-80 are to be marked as CLOSED. > > > > == Appealing this Decision == > > > > If anyone strongly disagrees with the content of the decision and would > > like to raise a Formal Objection, they may do so at this time. Formal > > Objections are reviewed by the Director in consultation with the Team. > > Ordinarily, Formal Objections are only reviewed as part of a transition > > request. > > > > == Revisiting this Issue == > > > > This issue can be reopened if new information come up. Examples of > > possible relevant new information include: > > > > * Use cases that specifically require the use of aria-labelledby with > > alt omitted. > > > > * Use cases that specifically require the use of role=presentation > > with alt omitted. > > > > * Examples of authors mistakenly or deliberately omitting alt when > > they might have otherwise, due to the generator mechanism exception. > > > > * Evidence that a great number of authoring tools are making wide use > > of the generator exemption, and that this interferes with proper > > inclusion of alt. (A list of possible generator values was provided > > in a Change Proposal, but there was no explanation of where it came > > from. Testing of content generators or direct statements of intent > > from implementors would provide sufficient evidence.) > > > > * A demonstrated trend towards more authoring tools fully supporting > > ATAG2, including the requirement to prompt for textual equivalents > > for images. > > > > * Examples of actual users who hand-author HTML emails incorporating > > images, and would find it overly burdensome to include alt. > > > > * Examples of other uses for the private communication exemption that > > are not covered by other exemptions. > > > > * Evidence that the number of implementations exposing title in an > > accessible way is decreasing, or that some existing implementations > > are unwilling or unable to expose it in an accessible way. > > > > * Evidence that implementations are unwilling or unable to expose the > > figcaption association to assistive technologies. > > > > > > === Arguments not considered == > > > > However, we should not do this as an attribute on each <img> > > element, since doing that would make it far more likely that > > authors will abuse the mechanism to shut up validators raising > > completely valid problems. Therefore we should limit this > > mechanism to page-wide "generator" meta tags. > > > > No proposal was made to make the generator mechanism per element, so > > this was disregarded. > > > > If any generated or missing mechanism is included in HTML5, it > > should only be included at the element level where it could be > > dealt with on an image-by-image case with a detection method such > > as a generated or missing attribute, rather than at the document > > level. > > > > Disregarded for the same reason. > > > > Additionally, some arguments were presented that a generator mechanism > > either should or shouldn't be at the element level rather than the > > document level. But since no Change Proposal actually proposed this, > > arguments for or against this position were disregarded. > > > > As Al Gilman said on behalf of PF, "WCAG WG is chartered to set > > Accessibility guidelines and HTML WG is not; so HTML5 should be > > careful to supply features that support WCAG and describe their > > use in ways that conform to WCAG." > > > > Gives no specific argument other than citing an authority. > > > > The feature to silence validators for authoring tools could be > > misused by authors who want to use a validator but don't want to > > give alternative text, but if that occurs (which seems unlikely) > > it is easy to resolve by changing the validator requirements to > > still clearly announce that the document is invalid while saying > > it's not the authoring tool's fault. > > > > This argues in favor of a mitigation that is not part of any Change > > Proposal. > > > > > > > > > > -- > with regards > > Steve Faulkner > Technical Director - TPG > > www.paciellogroup.com | www.HTML5accessibility.com | > www.twitter.com/stevefaulkner > HTML5: Techniques for providing useful text alternatives - > dev.w3.org/html5/alt-techniques/ > Web Accessibility Toolbar - > www.paciellogroup.com/resources/wat-ie-about.html > -- with regards Steve Faulkner Technical Director - TPG www.paciellogroup.com | www.HTML5accessibility.com | www.twitter.com/stevefaulkner HTML5: Techniques for providing useful text alternatives - dev.w3.org/html5/alt-techniques/ Web Accessibility Toolbar - www.paciellogroup.com/resources/wat-ie-about.html
Received on Wednesday, 4 May 2011 09:58:02 UTC