Making PDFs More Accessible: Text, Reading Order and OCR

Accessibility is more than visual appearance

A PDF can look polished on screen while being difficult for a screen reader or keyboard user. Accessibility depends on whether text is real text, the document has a meaningful structure, reading order makes sense, images have useful alternatives, and forms can be navigated and understood. A scan of a printed page may preserve appearance but provide no selectable text at all. OCR is one step toward access, but it does not automatically create headings, table relationships or correct reading order.

If the PDF is important to a public service, education, employment or a customer transaction, evaluate the document with assistive technology and the relevant accessibility standard. Visual inspection alone cannot establish conformance. A document may need remediation in its source application and then a fresh PDF export.

Start with selectable text and language

Check whether text can be selected and copied. If the page is a scan, OCR may provide a text layer, but inspect recognition carefully. Set the document language and mark language changes where the format and authoring tool support them. This helps screen readers choose appropriate pronunciation rules. Confirm that text is not encoded in a way that produces scrambled characters when copied.

For multilingual documents, verify each script and reading direction. Right-to-left text, mixed numerals and complex scripts can expose issues that are not obvious on a single-language sample. Use a representative page from every language and document style when testing a conversion workflow.

Headings, lists and reading order

A structured PDF can expose headings, paragraphs, lists and tables to assistive technology. Without structure, a viewer may read content in the wrong order, particularly across columns, sidebars or complex forms. Use semantic heading levels and real list structures in the source document instead of formatting every heading as ordinary bold text. For multi-column layouts, verify that the reading sequence follows the intended order rather than jumping between columns.

After exporting, test the reading order with a screen reader or accessibility checker. Fix the source file where possible, because repeated manual repairs in the PDF can be difficult to maintain. Check page numbering, repeated headers and footers so they do not interrupt the reading flow unnecessarily.

Images, tables and forms

Informative images need meaningful alternative text; decorative images should not create noise for assistive technology. Tables should have clear header relationships and a logical cell order. Complex tables may be easier to understand if simplified or accompanied by a text summary. Form fields need labels, logical tab order and instructions that do not rely on color alone. A signature field or checkbox that is visually obvious may still be confusing if its accessible name is missing.

Do not use alternative text to repeat a long paragraph already present in the document. Describe the purpose or relevant information conveyed by the image. For data tables, preserve row and column context so a screen reader user can understand which heading applies to each value.

Contrast, links and final testing

Ensure text has sufficient contrast against its background and do not communicate meaning by color alone. Links should have descriptive labels rather than generic phrases such as “click here.” Make sure interactive elements can be reached by keyboard and have a visible focus state where applicable. Avoid using a scanned screenshot of text when actual text can be provided.

Run an automated checker as a starting point, then manually inspect the document with keyboard navigation and a screen reader. Automated tools can find some structural problems but cannot judge every reading-order or content issue. Keep the accessible source document so future updates do not have to repeat remediation from scratch.

Practical checks and workflow recommendations

Accessibility review should include people who use the document in different ways, where practical. A keyboard-only user may discover focus-order problems that an automated checker misses, while a screen-reader user may identify confusing headings or table navigation. Ask reviewers to perform realistic tasks such as locating a section, completing a form or comparing table values rather than merely opening the document and saying it looks fine.

When remediating a PDF, start with the source document if it is available. Correct heading styles, list structure, alt text, table headers and language settings before exporting again. Fixing the source makes future versions more consistent and reduces the risk that the next update loses accessibility work. If only the PDF exists, document the remediation steps and retain a clean original.

Do not treat OCR confidence as an accessibility score. A page may be searchable but still have poor reading order, missing headings or unlabeled controls. Conversely, a well-tagged PDF can still contain OCR mistakes that change a number or name. Review textual accuracy and semantic structure as separate quality dimensions.

For recurring publications, create a release checklist and test the final file after each update. Fonts, page breaks, new charts and changed tables can introduce new barriers. Accessibility is an ongoing quality practice, not a one-time conversion setting, and should be included in the normal document publishing process.

Examples and edge cases

Example: a chart has excellent contrast and a clear legend, but its image has no alternative text. A screen reader may announce only “image” and provide no access to the key result. Add concise alternative text or a nearby text summary that communicates the chart’s purpose and important trend. Avoid copying every visual detail into an overly long alt-text field.

A document can pass an automated checker and still have an illogical reading order across columns. Navigate it with a screen reader and confirm that headings, paragraphs, tables and footnotes appear in a sensible sequence. Manual testing catches content-level issues that cannot be detected from the presence of tags alone.

If the PDF is updated regularly, keep the source document and accessibility checklist together. New tables, headings and charts can introduce barriers even when the previous version was accessible. Include accessibility review in the normal publishing process and retest the final exported file rather than assuming settings carried forward correctly.

A final review checklist

Test the tasks a real reader needs to complete: navigate by headings, read a table, understand an image, follow links and operate every form control using a keyboard and screen reader. Automated checkers are useful but incomplete. Record defects and retest after corrections. Keep the source document and accessibility checklist together so future revisions do not lose semantic headings, alternative text, language metadata or correct reading order.

Related PDFKaj tools

Use Merge PDF, OCR PDF, Compress PDF or browse the full tool directory where relevant to your task. Tool availability and behavior vary by feature, so read each tool’s privacy notice and verify the output.