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Re: PDFs and NVDA


From: LSnider
Date: Aug 21, 2011 5:54PM

Hi Duff,

Yes, headings was correct LOL.

I asked about the reading order differences in Acrobat/Reader because I
always thought there was a default reading order that would help screen
readers. What confused me was that I had to set it to tabbed reading order
in my version of Acrobat, as it wasn't the default for my Acrobat 9 program.
It seems like it would be better to have that as the program default, but I
am sure there is a reason why it was done that way.

I hadn't realized that about other PDF programs, good to know. I have used
Acrobat since it was created and always liked it best, so I don't use the
others much unless a client asks for it.

Yes I played with Word a lot over the years and in 2007 (I am going to
install 2010 next week) I like the fact that you can create PDFs that are
already tagged, nice feature.

Okay, that is what I thought about the tagging, so thanks for confirming
that for me.

Very good reasons for tagging, and thanks for the information on the touch
up tool. I strive for good source documents, so good to know that is the way
to go.

Thanks again!



On Sun, Aug 21, 2011 at 2:42 PM, Duff Johnson < <EMAIL REMOVED> > wrote:

It's not that "most people" use the tagged reading order... it's that tags
> are the ONLY place for logical structure, which is vital to the reliable
> reading and navigation of a PDF using AT. That said, many (most)
> applications OTHER than Adobe's are unable (at this time) to create or
> process tags in a PDF. Microsoft Office supports tagged PDF generation from
> Word files, and so does Open Office.
> Key point: The tags COME FROM the headings (not "headers", per Bevi).
> Software that supports creation of accessible PDFs from the source file will
> convert the structures present in the source file into corresponding PDF
> tags. So, exactly as you surmise... use good structures in your source file,
> and you have the right to expect a matching structure in your PDF.
> PDFs generated by software that does not support tagged PDF for output may
> be handled for accessibility purposes in two basic ways.
> 1) The "raw print stream" (PDF name is "reading order" - see earlier
> threads). In practice, this is what most software reads instead of the tags.
> The results range from "so-so" on extremely simple documents to "chaotic" in
> other cases.
> 2) Some interpretation of the raw print stream using other information
> (page-position, font size, font choice, etc, etc).
> It should be noted that both of the above approaches are totally
> illegitimate with respect to accessibility. There is only one option that
> can comply with WCAG 2.0 - support for tagged PDF in all its particulars.
> Yes... some users get good use from software that (primarily) uses reading
> order (cell phones, for example), but that's simply an example of something
> being better than nothing.
> That tool tweaks BOTH the raw print stream order (content order) AND the
> tag order. While this is not an unreasonable thing to do in the right
> circumstances, execution is everything, and I do not recommend the use of
> this tool in its current manifestation for this purpose.
> The first part... focus on getting the source file as good as possible so
> that tweaking in Acrobat or with other tools is minimized... is exactly
> correct.
> Otherwise... all the fixup following file creation can generally be done in
> the tags panel. Some of the Touch Up Reading Order Tool elements can be
> handy, but it's not a great tool, sorry to say.
> Duff Johnson
> p +1.617.283.4226
> t http://www.twitter.com/duffjohnson
> w http://www.duff-johnson.com