Scanned PDF vs. Screen Reader: Before and After the PREP Tool
Today’s blog post explores how the PREP Tool by Continual Engine can speed up document remediation and how a screen reader handles the same PDF before and after processing.
The starting point is a scanned PDF with a fairly complex layout. Because the document contains images of text instead of machine-readable text, a screen reader cannot access the words.
Video Guide
Scanned PDFs need remediation
A scanned PDF may look readable on screen, but the underlying file contains no accessible text. A screen reader needs actual characters and document structure so it can identify headings, paragraphs, and reading order.
In a traditional Acrobat workflow, you need to run OCR, tag the document, review the tags, and check the recognized text for errors. That process takes time, especially when the original scan includes unusual fonts, poor image quality, or a complicated layout.
The PREP Tool helps move those first steps forward automatically.
Process and review the PDF
From the PREP Tool dashboard, select Upload File, drag the PDF into the upload area, and upload it. The dashboard tracks the file while the tool processes it and keeps previously processed documents available for review. Once processing finishes, open the file to review the automatically generated tag structure.
Next, use Preview to review the text extracted from the scanned pages. Accurate OCR matters because a tagged document can still be difficult to use if the recognized text contains errors. In the video example, the PREP Tool correctly recognized the scanned text in about 10 seconds, making it easy to verify the content before export.
If you spot incorrectly rendered text, select Edit OCR Text to delete or add characters, correct misspellings, and fix other recognition errors without leaving the remediation workflow.
Export the corrected PDF
After reviewing the OCR text, select the export option and choose Export as PDF. Apply the export to all pages, submit the job, and download the processed file.
Open the exported PDF and review the Tags panel to confirm the document structure. Headings, paragraphs, lists, tables, and other content should have appropriate tags and follow a logical reading order.
Test the document with a screen reader
The most important check is how the document behaves with assistive technology. We used NVDA, a free downloadable screen reader. Launch NVDA, open the exported PDF, and navigate through the content.
In our video test, NVDA recognizes the first item as a heading level one, and then reads the document text as shown in the tags panel. The screen reader easily accesses content that was completely unavailable in the original scanned version.
Why screen reader testing matters
A tagged PDF can still contain accessibility problems. Tags may appear correct while the reading order is confusing, headings are misidentified, or OCR errors remain in the text.
Testing with a screen reader helps you catch issues that a visual inspection may miss. It also shows how the document behaves for someone who depends on assistive technology rather than the visual layout.
A useful remediation workflow combines automated processing with manual review and screen reader testing. The PREP Tool handles much of the repetitive setup, while you retain control over text corrections and final verification.
A faster starting point for PDF accessibility
The main advantage of the PREP Tool is speed. It can take an image-only PDF, recognize the text, add initial document structure, and give you tools to review the result before export.
The PREP Tool reduces repetitive setup work so you can spend more time reviewing and correcting the parts that require human judgment. For complex scanned PDFs, that stronger starting point can make remediation considerably more efficient while keeping accessibility verification in the workflow.
Let me be your champion for inclusion. I offer tailored solutions (and self-paced courses!) to ensure your documents meet and exceed compliance expectations. For more detailed insights, tutorials, and in-depth discussions on accessibility and related topics, don’t forget to check out my YouTube channel: The Accessibility Guy on YouTube. Subscribe for regular updates!
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