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Re: Z-Order and Tag Order Need to Match?

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From: Duff Johnson
Date: May 28, 2020 6:56AM

Hi Lisa,

There are no "multiple layers" in the PDF in this sense of the term. There is simply... content and tags.
Content is text, graphics, form fields, annotations, etc.
Tags are semantic structures (H2, P, Table, etc). These are applied to content and are used to describe "info and relationships' as per WCAG SC 1.3.1. Tags are the only means of providing these structures in PDF.
Otherwise I fully agree with you, and am very encouraged to hear that you are working to convince other software developers to improve their support for Tagged PDF.

Duff.

> On May 28, 2020, at 07:53, L Snider < <EMAIL REMOVED> > wrote:
>
> Hi Duff,
>
> Unfortunately I know all about these layers, but there is still no reason.
> There is no reason to have multiple layers, what you see should be what you
> get...whether you print, tag or whatever...This is partially why, in my
> personal opinion, PDFs are still inaccessible. 90% of the ones I have seen
> since 2000 are a problem in some way, and most in major ways. Plus tags are
> just one aspect of PDFs, people will all sorts of disabilities use PDFs as
> you know well.
>
> I gave up on Adobe, they moved forward for a long, long time and the last
> 10 years they moved backward. Not in InDesign, InDesign is amazing and
> kudos to whoever worked on the accessibility aspect of it, now if they
> could move back those people to PDF we might get back to where PDF
> was...Microsoft has been kicking butt in terms of accessibility the last 5
> years, so maybe one day Adobe will follow suit.
>
> I am now trying to find other PDF creation programs and convince them to do
> better, may have a shot!
>
> Cheers
>
> Lisa
>
> On Wed, May 27, 2020 at 7:48 PM Duff Johnson < <EMAIL REMOVED> > wrote:
>
>> Hi Lisa,
>>
>> Content order and logical reading order are "separate" in PDF because the
>> technology is obliged to represent content for different purposes.
>> Rendering (e.g., printing) is a different purpose than accessibility, for
>> example, and often requires ordering of content for processing purposes
>> that differs from logical reading order. PDF was originally designed for
>> maximum fidelity in print. Accessibility considerations were only addressed
>> in 2000 with the addition of the Tagged PDF feature to the format.
>>
>> In 2020 the difficulty is not in the format but in the software.
>> Unfortunately it remains the case that...
>> PDF viewer developers don't do a great job of supporting tagged PDF in
>> many cases. This is simply a business decision.
>> Users continue to use software that doesn't understand tagged PDF instead
>> of seeking out and demanding better.
>> Authors continue to author content without consideration for semantics
>> (e.g., use tab stops instead of table structures, etc.)
>> I'll beat my usual drum once again: if you want better PDF support,
>> complain to those who make your software. Demand better support for Tagged
>> PDF. In 2020 there's simply no excuse.
>>
>> Duff.
>>
>>> On May 27, 2020, at 18:30, Paul Rayius < <EMAIL REMOVED> > wrote:
>>>
>>> As per ISO 32000, one of the intents of PDF is that the "accessible
>> layer" and the visual layer are independent of each other.
>>>
>>> Paul Rayius
>>> Director of Training
>>> CommonLook
>>>
>>>