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Re: PDFs and NVDA

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From: LSnider
Date: Aug 21, 2011 1:21PM

Hi Duff,

Thanks for your answers, much appreciated. So a few follow up questions:

-If most people use the tagged reading order, what are the uses for the
other reading orders in Acrobat/Reader?

-If I don't use proper headers in a Word doc (which will be made into the
PDF), the tagging can't tell what is a header, correct? It just guesses? To
me with my testing, it seems like it guesses and I think that is what you
said below, but just wanted to confirm.

-The touchup reading order in Acrobat can be used to tweak what the tagging
does? I haven't used that one a lot before...I usually try to make well
structured documents in Word and they usually come out okay, but maybe I
should be using that touchup tool..

Thanks again, this is very helpful.

Cheers

Lisa


On Sun, Aug 21, 2011 at 11:26 AM, Duff Johnson < <EMAIL REMOVED> >wrote:

> Yes. Heading structure may be found in the tags. In PDF, there's no other
> proper place to look for it (I'm leaving aside a technically available but
> nonetheless pointless option).
>
> Since tags are the only place in which to find the file's logical structure
> (sequence, nesting and semantics), yes, you need Acrobat/Reader/3rd party
> option to use the "tagged reading order".
>
> Tags are essential to accessible PDF, period. The only exception (in a
> purely operational sense) would be a document that is so simple that it's
> possible to have the raw print stream (thanks Karen!) just happen to match
> the document's logical structure.
>
> As such, there is no "rule' about what to do in the absence of tags - there
> are merely a couple of options, both of them bad.
>
> In the case of an untagged PDF, applications can either (a) follow the raw
> print stream or (b) possess the smarts to analyze the page layout and make
> choices that override the as-printed sequence.
>
> An untagged PDF - even if all the content just happens to occur in correct
> reading order - is semantically equivalent to a single giant <P> tag
> containing all the text in the PDF - unacceptable for accessibility
> purposes.
>
> I hope this helps.
>
> Duff Johnson
>
>