Checking a PDF for AI writing: verify the text before the score

Two PDFs can look identical and contain different data. One stores selectable text; the other is a picture of a page. Before asking whether a PDF contains AI writing, check whether its words can be extracted accurately.

This checklist does not claim that Certaffy supports every layout, performs OCR on every scan, or can establish authorship from an image.

Start with a copy-and-paste check

Select a paragraph in a PDF reader and paste it into a plain-text editor. Compare it with the page. Check the first and last sentence, punctuation, paragraph order and special characters. Sample several pages rather than only the first.

If words cannot be selected, the file may be image-only. It needs reliable extraction or optical character recognition before text analysis is meaningful. Proofread OCR output: recognition can confuse numbers, drop lines or reorder columns. Keep the original for comparison.

Watch for layout problems

• Columns: sentences may become interleaved rather than read top to bottom.
• Headers and footers: repeated page furniture may appear in the body.
• Tables and slides: labels may arrive without their visual relationships.
• Line wrapping: broken words or missing spaces may alter the input.
• References and quotations: check what is excluded and which text the percentage describes.

Do not rewrite a document to obtain a preferred score. Correct extraction errors while preserving its actual words, and record any conversion.

Compare paste with upload

Use the same version. A paste test that omits the bibliography or a page is not equivalent to an upload. Extraction and exclusion rules can explain different outputs; a difference alone does not establish which result is correct.

For a functional check, choose a non-sensitive sample. Verify that the upload finishes or explains its error, that extracted text remains recognisable, and that any available downloaded report opens and refers to the same input. Successful transfer is not an accuracy test.

When a result should remain inconclusive

If an application reports insufficient text, unsupported content or an extraction problem, do not reinterpret it as “human.” A missing numeric score is not a zero. Resolve the input problem or seek other evidence.

Certaffy's upload-format overview and your academic or business workspace describe the available workflow. Features depend on the account and deployed service. Password-protected files, scanned pages and complex layouts should be checked explicitly, not assumed to work.

Read our AI-score guide before drawing conclusions. Highlights identify passages for review; they do not reconstruct writing history.

Prepared with AI assistance for Certaffy. This is a practical preparation guide, not a PDF/OCR benchmark or guarantee of format support.