How to make an accessible PDF that screen readers can follow

An accessible PDF from Layout by Zaweba starts with a few habits: give every meaningful picture alt text, mark purely decorative objects as decorative, check the reading order, set export tagging on your paragraph styles so headings become H1 to H6, then export with the Accessible (PDF/UA style) preset. Layout builds the tagged PDF itself, including lists, tables with header cells and summaries, notes and links, so the work is mostly in preparing the document well.

An accessible PDF is one that assistive technology can read properly. A sighted reader takes in a page at a glance. A screen reader needs to be told what is a heading, what order the text runs in, what a picture shows and which cells head a table. Without that, a beautifully designed brochure can come out as a jumble.

Groundwork in the document

You need a document built with paragraph styles rather than hand formatting, because the styles are what tell Layout which text is a heading and at what level. If your headings are just body text made bigger, sort that out first. You also need a few minutes per picture to write sensible alt text, and the patience to look through the reading order once.

Tagging, alt text and reading order

Begin with the styles. Each paragraph style has export tagging, which sets the tag and class it becomes in the PDF. Set your main title style to H1, section headings to H2, and so on down. Body text stays as ordinary paragraphs. Because the tag lives in the style, every heading in the document picks it up at once.

Next, the pictures. Select each one and add alt text that says what the picture is for in this context, not every detail in it. A product photo might need the product's name and colour. A chart needs the point it makes. Logos, flourishes and background textures that carry no meaning should be marked as decorative instead, so the screen reader skips them rather than announcing something unhelpful.

Tables come next. Mark the header cells as headers and give the table a summary, which Layout includes in the tagged PDF. Then open the Reading order panel and look at the order the content will be read in. On a simple page it will match what you expect. On a magazine page with sidebars, pull quotes and captions it is worth checking that the main story reads straight through and the extras come where a listener would want them.

Fill in File info for the document, then run live preflight with the Accessible profile. It looks for the problems accessibility rules care about, and clicking each one takes you to it.

Finally, export with the Accessible (PDF/UA style) preset. Notes and links are tagged along with everything else.

Checking the result

Layout can check its own output. File > Check a PDF tests the exported file against PDF/UA-1 rules and shows its structure tree. The tree is the clearest view you will get of what a screen reader meets: headings in order, figures with their alt text, tables with their header cells. Layout says plainly that this is not a certified validator, so if your organisation has a formal testing process, use that as well. The check is there so you arrive at it with the obvious problems already fixed.

Habits that make it easy

Write alt text as you place pictures rather than at the end, when there are fifty to do and the temptation is to write "image". Keep heading levels in order and don't skip from H1 to H4 because you like the look of that style. If you also publish the document as an EPUB, the same groundwork helps, and Layout has EPUB accessibility metadata to fill in alongside.

Most of this becomes habit after one document. Build the styles properly once, save them in a template, and every later job starts most of the way to an accessible file.