PAC: PDF Accessibility Checker and Correct Tagging Syntax Errors for 508 PDFs

• All tags should be under a <Document> tag.

Best practice at this time, but will probably be required in a future standard.

• A <Reference>, <Note>, or <Link> tag should be under another tag, like a <P> tag.

All 3 tags — <Reference>, <Note>, and <Link> — are inline level tags and, therefore, should be nested inside another tag like <P>.

However, checkers are sloppy about checking for this hierarchy and syntax, and most screen readers (at this time, 2021) don't recognize or fully utilize these tags at all. For example, MS Word with PDF Maker, will create this tag structure, and it works fine with today's screen readers, even though it is not correct per the PDF/UA-1 standard:

<P> Body text with a footnote reference <Reference>1

<Note>1 Footnote text directly follows the paragraph with the footnote reference.

In this example, the <Note> is used at the block level (that is, equal in hierarchy of the <P> tag and not nested inside it). Something similar is created with Adobe InDesign.

Conclusion: This is a best practice at this time because none of the PDF conversion utilities accurately build the correct tag structure for these items. Luckily, most A T ignore these tags, anyway.

• A <Reference> tag should not be used directly for a <Link> tag, but should include a <Link> tag as a child of it.

If you mean that <Reference> can't be substituted for a <Link> tag, then you're correct. There is a bit of confusion about how these tags are defined and their relationship. But you're right, If there is a hyperlink on the <Reference> tag, then a <Link> and it's child tag <Link-OBJR> must be nested inside the <Reference> tag.

• <Artifact> tags, such as created from images marked as "Decorative" in Word, or as created automatically in a number of tables in converted documents, are not defined (and so I remove them from the document).

The <Artifact> tag is not part of the PDF/UA-1 tag set. It's being developed for the forthcoming PDF/UA-2 standard, which who knows when that will be released (and I'm on the PDF/UA standards committee!).

So it will not work with current A T, and if left in a PDF at this time (2021), will be voiced as "artifact" by screen readers, which defeats the purpose of artifacting something! So artifact out the <Artifact> tags via the Content panel.

This is a definite case where the code jockeys who are on the standards committees are "jumping the gun" on the standard and programming in items that aren't even standardized yet. Produces errors in our documents, and can wreak havoc on our end users, like hearing "artifact."

So use PAC3, not earlier versions, and ignore some of the off-the-wall "errors" it flags.

And use a better color picker, such as WebAIM.org's contrast checker. It's one of the most objective contrast checkers because they're not out to sell you a product or service.  In our shop, we use PAC3 + internal Acrobat Checker to catch as many items as possible.

PAC 3 is the wat to go.

For color analyzer, go here

https://webaim.org/resources/contrastchecker/

Or get this free one, I have used it for years.

https://github.com/ThePacielloGroup/CCAe/releases/tag/v1.2.1