Re: [html4all] the alt attribute debate

>Likewise, if one pipe (e.g. digital camera) gives you bitmaps without
>textual alternatives and another pipe (the Web) insists on textual
>alternatives being present, you can be 100% sure that the person
>writing the piece of software that stuffs images from the camera to
>the Web will fake the textual alternatives by emitting bogus data.

your  argument presupposes that the writers of the software give a damn
about making their apps output valid  code:

a quick check of numerous photo sharing sites (for example) appears to
indicate otherwise:
flickr home page Failed validation, 31 Errors
photobucket homepage Failed validation, 109 Errors
webshots home page Failed validation, 150 Errors


On 25/09/2007, Henri Sivonen <hsivonen@iki.fi> wrote:
>
> On Sep 24, 2007, at 15:40, Philip TAYLOR wrote:
>
> > Henri Sivonen wrote:
> >
> >> By decoupling syntactic correctness from simplistic machine-
> >> assessable accessibility testing, an incentive to pollute the non-
> >> visual user experience with bogus alt text is removed.
> >
> > Henri, your assertion may well be true, but even as a native
> > speaker I find it hard to work out what you are trying
> > to say here : could you possibly re-cast your assertion
> > into more straightforward language, so that the slower
> > amongst us might be able to follow your argument ?
>
> There are two things to check:
> 1) Is a document syntactically correct?
> 2) Is a document accessible?
>
> The exact definitions of "syntactically correct" and "accessible" do
> not need to be specified for now except for the alt issue.
>
> "Does this image have a textual alternative?" is part of the test "Is
> this document accessible?". Merely checking for the presence of the
> alt attribute (even with the empty string as the value) is a
> simplistic machine-assessable accessibility test. It doesn't tell,
> for example, if the alt text is any good. Also, if someone cares
> about passing the check but not about actually making pages
> accessible, it is easy to fool the machine check by using a bogus
> value--any value will do. Hence, "simplistic".
>
> Those who advocate that the check for syntactic correctness should
> also contain the test "Does this image have an alt attribute?" want
> to couple (simplistic) accessibility testing with syntactic correctness.
>
> For people other than accessibility advocates, #1 and #2 are seen as
> different things. Moreover, experience shows that there are people
> who want address #1 doing whatever collateral damage it takes. (I
> doesn't really matter if you think that other people should see #1
> and #2 as the same. They don't, so your strategy should adjust to that.)
>
> Insisting on coupling #1 and #2 makes people who only consider #1 put
> in bogus values for the alt attribute. Not coupling #1 and #2 removes
> the reason to put in the bogus values.
>
>
>
> Epilog:
> When a software developer wants to move some bits from one pipe to
> another and the second pipe wants something the first pipe doesn't
> provide, the software developer *will* fake it with bogus data if (s)
> he don't have the required additional data. Every time you insist on
> getting some data that the provider doesn't have, you should expect
> to get bogus data. Insisting that datum A cannot be communicated
> unless it comes together with datum B fails to always leads to datum
> B getting faked some of the time if there's value in communicating
> datum A.
>
> For example, if you are a kernel developer and you are copying files
> from a file system that doesn't record the creation dates of files to
> another file system that insists that every file *must* have a
> creation date, you don't tell your boss/customers/whatever that you
> can't copy the files. Instead, you fake the creation date (the
> current time from the clock, the start of the epoch, whatever).
>
> Likewise, if one pipe (e.g. digital camera) gives you bitmaps without
> textual alternatives and another pipe (the Web) insists on textual
> alternatives being present, you can be 100% sure that the person
> writing the piece of software that stuffs images from the camera to
> the Web will fake the textual alternatives by emitting bogus data.
>
> --
> Henri Sivonen
> hsivonen@iki.fi
> http://hsivonen.iki.fi/
>
>
>
> _______________________________________________
> List_HTML4all.org mailing list
> http://www.html4all.org/wiki
>



-- 
with regards

Steve Faulkner
Technical Director - TPG Europe
Director - Web Accessibility Tools Consortium

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