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Re: Accessible PDF - syncing reading order and tags tree order

for

From: chagnon
Date: Jul 15, 2019 2:25PM

Whew!
That's a lot of questions.

Difficult to answer them in depth; you're asking for our 3-day hands-on
class in 508 + InDesign in a short email <grin>.

Some basic principles first, and then I'll give specifics for your questions
afterwards.

From what you've described,
- it's not as difficult to do as you stated.
- it's also not as easy as you stated.

Best Practice: always create the most accessible source document as possible
before exporting to PDF. There are no tools that can adequately and quickly
correct the PDF once it's been made. Especially with PDFs from InDesign; not
that InDesign is a bad program (far from it!), it's that it's a highly
complex program used to make very visually complex documents.

InDesign is a page layout and design program. MS Word is just word
processing.

For those not interested in the details, there's no further need to read on.

For the rest who are InDesigners, here we go...

<Quote> then reorder the layers and add tags to document</Quote>
The phrase "add tags" has me worried.

You do not add tags to InDesign (or Word, PowerPoint, or any other source
document).

PDF tags exist only in PDFs. If you are using tags in InDesign, then they
are XML tags (listed in a panel called "Tags" that I wish Adobe would rename
"XML Tags"). XML tags are not the same as PDF tags which are not the same as
HTML tags. So if you are using InDesign's tags panel, don't!

PDF Tags are added to a document at the time it is exported (or converted)
to the PDF file format.

While you're creating the source document, you indicate which tag should be
applied to the exported PDF by using Paragraph Styles. (See Export Tag in a
style's definition dialogue box.)

<Quote> that NVDA doesn't follow reading order, it follows the tag tree
order</Quote>

The PDF/UA standards require that all assistive technologies follow the Tag
Tree for everything...tags and reading order. So in theory, you shouldn't
worry about the Order panel.

But in reality, you should get it into decent shape because:
-The order panel is used by many technologies, including when someone just
wants to read a PDF on their cell phone.
-Older AT still use the order panel (such as one of our government clients
that has an older model Braille embosser).
-A lousy Order panel can sometimes make it more difficult to get the Tag
Tree correct, especially with complex visual designs such as those from
InDesign.
-It's often faster to correct Tag tree errors in the Order panel; when done
in the Order panel, they generally are done in the Tags tree, too. But not
vice versa.

<Quote> - Is there a way to force the tags to sync with the Reading Order
panel? </Quote>

Change something in the Order panel and it will change in the Tags tree.
But change something in the Tags tree and it will NOT change in the Order
panel.
And there is no magic button to force them to synch.

Best Practice: control both the Tag and Order reading orders in InDesign,
not after the PDF has been made.

<Advice>
InDesign controls the tags via Paragraph Styles. So use paragraph and
character styles exclusively and ditch the top control panel (or its new
replacement, the Properties panel).

InDesign controls the TAG reading order mainly by how well you have threaded
your story frames and controlled their sequence.

InDesign controls the Order Panel's reading order (originally called the
architectural/construction order) by the sequence in which you added each
frame to the page (hence, the stacking order seen in InDesign's layers
panel). The bottom-most item on the bottom-most layer will be read first,
and the remaining ones on that layer. Then it goes to the next layer,
bottom-up.

Strategy: merge down multiple layers into one; otherwise they will throw off
both the Tag and Order panels reading orders. Becomes a waste of time to
have multiple layers.

The Articles panel can help, but really doesn't do much to either reading
order. But do use it. Set it up as the last thing you do before exporting.
Focus on controlling the reading orders via the other methods above, namely
threading your story frames and the controlling the stacking order in the
layers panel.

The order in InDesign's Articles panel is top down.
The order in InDesign's Layers panel is bottom up.

Hope this helps,
-Bevi

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Bevi Chagnon, founder/CEO | <EMAIL REMOVED>
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