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Re: Untagged PDF doc with table structure


From: Bim Egan
Date: Feb 18, 2015 8:12AM

Lynn didn't seem to be talking about using Acrobat though. She described
the experience of many screen reader users in finding a table in an untagged
PDF when opened in Reader, and she asked why this could happen. Her
message said that the Acrobat installation wasn't accessible.


-----Original Message-----
[mailto: <EMAIL REMOVED> ] On Behalf Of Andrew
Sent: 18 February 2015 14:36
To: WebAIM Discussion List
Subject: Re: [WebAIM] Untagged PDF doc with table structure

Jon is correct. When Acrobat opens an untagged document and there is a
client that is using the accessibility API data running, Acrobat (or Reader)
will add tags to the document. The result is the same as if an author used
the "add tags" feature in Acrobat. You get Acrobat's best interpretation of
what the tags should be. That will sometimes result in headings,
well-formed tables, lists, and other structures. Authors who use this
feature in Acrobat know that you generally need to fix some of the tags.

The result is that the document is tagged temporarily and assistive
technologies recognize and use the information.

The dialogs that you see when opening PDF documents give you some
information about what is going on. To understand better, here's my

In acrobat or Reader preferences there is a "Reading" category. There is a
checkbox that is labeled "Confirm before tagging documents". If this is
checked, then every time that Reader intends to tag an untagged document the
"Reading an untagged document with assistive technology" dialog pops up and
the user needs to confirm that this is what they'd like to do. If the user
selects cancel then the document won't be tagged and the reading experience
will be essentially non-existent.

If you elect to allow the tagging, there are other options as mentioned in
one of the replies. I recommend using the "infer reading order from
document" option.

There are other settings related to large documents and auto-tagging.
Autotagging takes time, so if you open a very dense 600 page manual you may
find that Reader takes a long time to do the tagging. It can, and we are
always looking to improve the efficiency of this process. The option for
the user is to indicate whether the autotagging should occur only on visible
pages, on all pages in the document, or on all pages except if the document
is "large". The user gets to define what large means - a user might find
that their system is slow at this so sets the limit at 25 pages, or might
set it higher if their system handles this process quickly. The down side of
only tagging a few pages at a time is that if there are recognized
structures on pages that haven't been tagged yet (e.g. a heading on page 51)
the user can't use screen reader heading navigation to jump to it because
the tags don't exist until the page is in view in the reader.

Hope this helps,


-----Original Message-----
[mailto: <EMAIL REMOVED> ] On Behalf Of Lynn Holdsworth
Sent: Wednesday, February 18, 2015 4:36 AM
To: WebAIM Discussion List
Subject: [WebAIM] Untagged PDF doc with table structure

Hi all,

Apologies if PDF accessibility is off topic. If so is there a list that
covers this?

But if not ...

I open a PDF document, and Adobe Reader alerts me that it's untagged.

So I begin to peruse it using JAWS, and come across a table whose structure
is robust enough for me to move around it using the JAWS table keystrokes.

Does this mean there *are* tags in the document after all? Or has Adobe
Reader used heuristics to add tags to improve the doc's accessibility, since
my settings flag up that I'm using a screenreader?

I tried to download a trial version of Acrobat Pro so as to examine the
document structure, but the download assistant seems inaccessible.

Thanks as always, Lynn

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