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Re: 1.4 recommeded additions to wording

From: Joe Clark <joeclark@joeclark.org>
Date: Wed, 3 Nov 2004 17:05:26 +0000 (UTC)
To: WAI-GL <w3c-wai-gl@w3.org>
Message-ID: <Pine.LNX.4.60.0411031657530.1840@aristotle.multipattern.com>

This has always been on the wrong track and is only getting worse. I 
expect you'll all continue to pretend I never told you that; I've been 
consistent about it for months.

> Level 3 Success Criteria for Guideline 1.4
>
> - Audio content does not contain background sounds or the background sounds
> are at least 20 decibels lower than the foreground audio content, with the
> exception of occasional sound effects. [V]

You have no proof whatsoever that this guideline actually provides 
accessibility benefit; there is no evidence at all that it can be met in 
the real world; the figure of 20 dB is purely arbitrary.

It seems the entire guideline is a sop to anticipated criticisms that 
Blind People Get Good Contrast But Deaf People Don't! Well, that's because 
the disabilities are intrinsically different.

> I had an action item to provide recommendations on 1.4 based on the open
> issues and my research. Until we come up with an alga rhythm much of this
> guideline is up in the air. One person recommended an extensive research
> study. (Bug#996) Ideally that would be a good idea. I wouldn't mind joining
> some people but it would require a team to conduct the size of study he is
> suggesting in order to get a statistically meaningful sample size. He also
> suggests it would require a statistician.

And I strongly doubt it would prove a benefit. Until such study is done, 
the Working Group must delete its guideline, since it implies here that 
the whole shebang is hypothetical.


> Who Benefits from Guideline 1.4 (Informative)
>
> Individuals with low vision can easily read characters in the content even
> if they don't have the wide field of view

Visual field is unrelated to colour perception.

> or full range of color perception used by fully sighted persons to 
> separate text from background images.

As I've explained for a year and a half-- even at the Toronto f2f, where 
Ben later went right ahead and pretended I had never proved my point-- 
colour deficiency requires accommodation only in confusable colours. In 
short, foreground and background matter only in the red/green and 
blue/green ranges. After several years of looking, I have found only rare 
examples of confusable colours used in confusable ways on the real Web 
that the Working Group either ignores or hates.

Accessibility for colour-deficient persons is a question of confusable 
wavelengths and has nothing per se to do with foregrounds and backgrounds.

> <new> This will also aid 
> comprehension for individuals with cognitive disabilities who benefit 
> from easy discernment of text.

OK, great, but every sighted person, according to the worldview of this 
guideline, requires "easy discernment of text."

> Visual contrast also helps individuals with hearing impairments who are 
> aided by clear visual representation of information </new>

Prove it. This sounds like grandstanding. What does being deaf have to do 
with psychologyof reading in this context?

-- 

     Joe Clark | joeclark@joeclark.org
     Accessibility <http://joeclark.org/access/>
     Expect criticism if you top-post
Received on Wednesday, 3 November 2004 17:05:33 GMT

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