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Thread: PDF Tag Nesting Question
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From: Jennifer Smith
Date: Wed, Jul 24 2013 7:45AM
Subject: PDF Tag Nesting Question
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Hi!
Our office is lucky enough to have two staff members working on making PDF documents accessible - most notably to adhere to 508 accessibility laws. The staff members have different backgrounds and training in accessibility and have a question about the proper/best way to tag a PDF - one staffer nests the tags and another does not. Is one more correct/more accessible than the other?
Non-nested example:
<H1>
<P>
<H2>
<P>
<P>
<L>
<H3>
<P>
<H2>
<P>
Nested example:
<H1>
<P>
<H2>
<P>
<P>
<L>
<H3>
<P>
<H2>
<P>
So, does the nesting or non-nesting make a difference in accessibility? Our team has limited resources to screen readers for testing and want to ensure we adhere to true accessibility and not just merely what an automated checker can validate.
In addition, the two staffers have differing approaches to using the <Sect> tags. One uses them, the other does not. Please advise as there are differing guidelines provided depending on the source.
Is there a definitive resource on how all of the tags should be used so these are less open to subjective interpretation?
Thanks in advance!
-Jen
Jennifer Smith
Danya International, Inc.
9 Corporate Boulevard | Suite 100 | Atlanta, GA 30329
Phone: 404-604-2734 | Mobile: 404-398-7746 | Fax: 404-679-7918
= EMAIL ADDRESS REMOVED = <mailto: = EMAIL ADDRESS REMOVED = >
www.danya.com<;http://www.danya.com/>;
From: Jonathan Metz
Date: Wed, Jul 24 2013 8:08AM
Subject: Re: PDF Tag Nesting Question
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Hello Jennifer!
To the best of my knowledge:
Non-nested example:
<H1>
<P>
<H2>
<P>
<P>
<L>
<H3>
<P>
<H2>
<P>
Is a ³Weakly Structured Document², and:
Nested example:
<H1>
<P>
<H2>
<P>
<P>
<L>
<H3>
<P>
<H2>
<P>
Is an example of a strongly structured document. For this particular
example, ISO 32000 (PDF 1.7) states that "At each level, the children of
the grouping element should consist of a heading (H), one or more
paragraphs (P) for content at that level, and perhaps one or more
additional grouping elements for nested subsections.² So you would replace
those headers with H¹s (no numbers).
There has been some debate about how most screen readers don¹t understand
strongly structured documents, but this is technically a more accessible
way to go, or maybe it was the opposite; I can¹t recall. I think I came
into that conversation in the middle. Anyway, the Weakly Structured
document, (IMO) is the best way to go because it involves moving the tags
around in the least amount of ways. It can be a real pain when you move
content into other content by accident and it vanishes. And man, I haven¹t
saved in, like, 15 minutes; and there is no Undo.
The one thing you want to make sure of with this, is that if you go with a
strongly structured tag tree, ONLY use H. If you go with weakly
structured, ONLY use Hn-Hn, but keep them in order. Don¹t mix H and Hn.
>>In addition, the two staffers have differing approaches to using the
>><Sect> tags. One uses them, the other does not. Please advise as there
>>are differing guidelines provided depending on the source.
I use the Sect Tag, and the Part tag (from time to time) but mostly in
really large documents. They do mean something, but I believe that Screen
Readers for the most part ignore these. They do however make for easier
bookmark creation in Acrobat. These are standard grouping element
structure types. I don¹t think a PDF is better or worse for not having one
aside from figuring out where you were when you need to go back and fix
something several years down the road.
>> Is there a definitive resource on how all of the tags should be used so
>>these are less open to subjective interpretation?
I think somethings are open to some degree of interpretation, where the
arguments for or against something relate to the degree of how universally
accessible something is. However...
ISO 32000 (PDF 1.7) is a document you can get for free (someone else will
probably provide a link, though google does a fine job). This is the
specification for PDFs as we know them today. It¹s crazy long, and written
for programmers, but it details what tags are, what goes in them and why
they are what they are.
ISO 14289 (PDF UA) is a document you have to pay for (it¹s about $110 I
think). You buy this from ANSI. This uses PDF 1.7 above as a serious
reference, but creates rules for creating an accessible document. This
should be the rulebook for PDFs, IMO.
Someone else needs to help me here, but there is a woman who created a
document on creating accessible PDFs a while ago. It¹s very expensive (I
think $70), but from what I understand it¹s worth every penny.
I hope this helps, and I was as accurate as I can be.
On 7/24/13 9:45 AM, "Jennifer Smith" < = EMAIL ADDRESS REMOVED = > wrote:
>Hi!
>
>Our office is lucky enough to have two staff members working on making
>PDF documents accessible - most notably to adhere to 508 accessibility
>laws. The staff members have different backgrounds and training in
>accessibility and have a question about the proper/best way to tag a PDF
>- one staffer nests the tags and another does not. Is one more
>correct/more accessible than the other?
>
>Non-nested example:
><H1>
><P>
><H2>
><P>
><P>
><L>
><H3>
><P>
><H2>
><P>
>
>Nested example:
><H1>
> <P>
> <H2>
> <P>
> <P>
> <L>
> <H3>
> <P>
> <H2>
> <P>
>
>So, does the nesting or non-nesting make a difference in accessibility?
>Our team has limited resources to screen readers for testing and want to
>ensure we adhere to true accessibility and not just merely what an
>automated checker can validate.
>
>In addition, the two staffers have differing approaches to using the
><Sect> tags. One uses them, the other does not. Please advise as there
>are differing guidelines provided depending on the source.
>
>Is there a definitive resource on how all of the tags should be used so
>these are less open to subjective interpretation?
>
>Thanks in advance!
>
>-Jen
>
>Jennifer Smith
>Danya International, Inc.
>9 Corporate Boulevard | Suite 100 | Atlanta, GA 30329
>Phone: 404-604-2734 | Mobile: 404-398-7746 | Fax: 404-679-7918
> = EMAIL ADDRESS REMOVED = <mailto: = EMAIL ADDRESS REMOVED = >
>www.danya.com<http://www.danya.com/>;
>
>>>
From: Olaf Drümmer
Date: Wed, Jul 24 2013 10:29AM
Subject: Re: PDF Tag Nesting Question
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Hi all,
these two variants are booth valid PDF syntax:
Non-nested example = weakly structured document:
<H1>
<P>
<H2>
<P>
<P>
<L>
<H3>
<P>
<H2>
<P>
Nested example = strongly structured document (note the use of H instead of H1...H6):
<H>
<P>
<H>
<P>
<P>
<L>
<H>
<P>
<H>
<P>
For practical reason - mostly lack of adoption by creation tools and by assistive technology - the weakly structured, non-nested approach is recommended.
Olaf
From: Chagnon | PubCom
Date: Wed, Jul 24 2013 11:14AM
Subject: Re: PDF Tag Nesting Question
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Olaf wrote: "the weakly structured, non-nested approach is recommended."
Yes! We agree on something, Olaf!
<grin>
Olaf's strongly-structured example is more akin to XML and its strict
hierarchy of information. That is not needed at this time for accessibility,
but might be if you're using an XML publishing workflow for automated
periodicals, journals, etc.
Bevi Chagnon
PubCom.com Trainers, Consultants, Designers, and Developers.
Print, Web, Acrobat, XML, eBooks, and U.S. Federal Section 508
Accessibility.