Accessible PDF export

Deckset can create PDF/UA-2 documents on macOS and iOS. In the export options, choose PDF or PDF (Reduced file size) and leave Create accessible PDF (PDF/UA-2) turned on. This option is on by default.

Before saving, Deckset runs its accessibility validation and reports problems it detects in the generated PDF. Accessible PDFs include tags for reading order, headings, lists, tables, links, and media descriptions. Regular PDFs use the same visual layout but are not PDF/UA-2 documents.

A successful export does not judge whether descriptions explain the content or whether the reading order makes sense to a reader. Review those with assistive technology, especially on slides with columns, diagrams, or charts.

Set the document language

Declare the presentation’s language at the top of the Markdown file when you know it:

language: ja

Deckset writes this value into the PDF and helps assistive technologies choose the right pronunciation and voice. If you leave it out, Deckset detects the main language from the presentation text. Use a BCP 47 language tag, such as zh-Hans, zh-Hant, ja, or ko.

Choose a page layout

PDF exports can place 1, 2, or 4 slides on each page:

  • 1 keeps the presentation’s slide size.
  • 2 places two slides on a portrait A4 page.
  • 4 places four slides on a portrait A4 page.

The layout applies to both accessible and regular PDFs. You can also include all build steps and presenter notes. When presenter notes are included in an accessible PDF, their text and links remain available to assistive technology.

Prepare accessible media

Informative images, audio, video, and Mermaid diagrams need a useful description. Add those descriptions and mark decorative media before exporting. See Accessible media for the alt(...), informative, decorative, and Mermaid description syntax.

For example:

![inline informative alt(Quarterly revenue increased by 18 percent)](revenue-chart.png)

Deckset treats a background image without a description as decorative by default. Foreground media is informative by default, so it needs a description or an explicit decorative modifier.

To catch missing or unrecognized media descriptions while you edit, turn on Show Accessibility Warnings in Presentation Options.

Resolve export issues

If Deckset cannot create a valid PDF/UA-2 document, the failed attempt does not create or replace the destination file. Choose one of the recovery actions:

  • Review Issues shows the problem, guidance, and affected slide when Deckset can identify it. Use Show Slide or Show First Affected Slide to return to the presentation.
  • Export Regular PDF tries again without PDF/UA-2 accessibility. The resulting file is a regular PDF.
  • Cancel closes the recovery flow without saving a PDF.

Fixing the source and exporting again is the best way to preserve accessibility. Use Export Regular PDF only when you intentionally need a regular PDF.