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Re: Untagged PDF doc with table structure

for

From: Jonathan C Cohn
Date: Feb 18, 2015 8:41AM

Andrew,

Is the only reason to not auto-tag the entire document a time initial issue? I generally have based my decision on the amount of RAM available on my system. If the document is quite large, and one has is already using most of the active RAM, will tagging a 100+ page document cause slow page changes because of swapping?
Thanks,

> On Feb 18, 2015, at 09:36, Andrew Kirkpatrick < <EMAIL REMOVED> > wrote:
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> 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.
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> The result is that the document is tagged temporarily and assistive technologies recognize and use the information.
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> The dialogs that you see when opening PDF documents give you some information about what is going on. To understand better, here's my explanation.
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> 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.
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> 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.
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> 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.
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> Hope this helps,
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> AWK
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