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Re: PDF Conclusion

for

From: Andrew Kirkpatrick
Date: Dec 8, 2009 10:42AM

Thanks for the reply Wayne, I'll address a few points within.

As Andrew pointed out, the issue is Accessibility
Support. This is a part of WCAG 2.0 Conformance,
and it is pretty tricky. It basically says that
if you include a medium in your web page then you
can only claim WCAG 2.0 Conformance at a given
Level (A, AA or AAA) if your medium supports a
reasonably attainable assistive technology at the
given conformance level. If no such attainable
assistive technology exists then the medium is not
accessibility supported. To meet conformance, a
site that includes a medium that is not
accessibility supported, must provide an
equivalent alternative medium that has
accessibility support at that desired conformance
level.

It is a little different than what you describe above. The issue is accessibility-supported _uses_ of technologies. For example, if a technology supported the display of tables but didn't support table headings, then it would be impossible to meet the success criteria relevant to table headings and using tables in that technology would not be deemed an accessibility supported use. You might find that this means that that technology could be used in accessibility supported ways just by avoiding tables, or there might be other issues with accessibility support for other success criteria.

You are saying that PDF isn't accessibility supported where text is used, which is clearly a more pervasive issue, but I do not agree with all of your points with regard to whether WCAG 2.0 requires them or not. This doesn't change whether they are valid enhancement requests for low-vision users, which of course they are.

There is no doubt that Guideline 1.3 and Criteria
1.3.1 cover the text level. The concept of
information and relationships with no dependency
on visual style is not confined to the tag level
(table, list, form etc.). It refers to
information, relationships and style with no
qualification. Given the precision of WCAG 2.0,
that language was no accident.

I'm sorry, but I disagree. I don't see style in the success criteria. 1.4.8 is where I believe you should be referring. I'm on the WCAG working group call every other Thursday - perhaps you should log an issue with the WCAG group to offer feedback?

Space indicates separation and sequential
relationships between letters, words and lines.
If these visual cues are imperceivable the
semantics of separation and sequential
relationships are lost. Now, as Andrew pointed
out, the programmatically determinable information
is present in the PDF document, but to date there
is no atainable assistive technology to present
this material in a form that is needed by moderate
low vision.

You're talking about separation of presentation from structure and semantics. PDF does this. Screen magnifiers support access to the underlying information - do screen magnifiers not count?

Likewise, characters (letters, numbers and
punctuation) are important semantic information.
It is difficult to read with reduced perception of
characters. If they are presented in the wrong
font family, they are very difficult to perceive.
Letters are information, and font family is
style. These fall under the scope of the
adaptability guideline.

Under 1.3.1? I disagree. Again, I think that you should request clarification from the WG.

My issue is this. Guideline 1.3 and Criterion
1.3.1 are not accessibility supported by any PDF
document at this time. 1.3 and 1.3.1 apply at the
text level, and no attainable assistive technology
exists to transform text style completely for PDF.
This, to me, means that one cannot use PDF and
conform to WCAG 2.0 Level A at this time without
providing an equivalent document that is
accessibility supported. We know that HTML is
accessibility supported so an option exists.

If you want to provide an HTML or Word or ODF or any other document along with a PDF, I have no problem with that. It doesn't matter to me what format anyone uses, but if they choose to use PDF then they should be able to do so with the knowledge that they can address WCAG 2.0 without a fallback. We've documented accessibility support for WCAG 2.0 with PDF at http://www.w3.org/WAI/GL/WCAG20/implementation-report/PDF_accessibility_support_statement and encourage people to take a look.

This is the last I will write on PDF on WebAIM for
a long time. The discussion has clarified my
thinking. Andrew, I am interested in giving
feedback to the reader group on the needs of
moderate low vision regarding PDF. I thank you
for your thoughtful comments. To those who asked
for more direct communication I'll get to you
soon. I've saved this discussion.

Thanks for your comments Wayne - we can chat about setting up some time.
AWK