Evaluate text PDFs and scanned PDFs separately
PDF is a container, not a guarantee of readable text. A selectable document, an image-only scan and a mixed PDF can expose different inspection paths. Evaluate each required form without assuming OCR is present or equally effective.
For Document security owners and technical evaluators
Three versions of a fictional service report
A facilities team wants an AI summary of a synthetic service report. The same fictional identifiers appear in a text export, a scanned copy and a PDF containing both forms.
What you are working with
- A text-based PDF with selectable synthetic identifiers in paragraphs, tables and page headers.
- A scanned counterpart containing only fictional values, with its image quality recorded in the test plan.
- A mixed PDF with a text page, an image page and a documented expected-removal checklist.
A safer approach
- Confirm text extraction and any OCR scope with the vendor before choosing the acceptance boundary.
- Use synthetic scans and mark poor-quality variants as separate tests instead of silently changing the fixture.
- Inspect the final file's visible content and available text layer; do not accept a colored overlay as sufficient proof.
Expected outcome: Each PDF class has a supported result or an explicit restriction, and any sanitized output satisfies both confidentiality and readability requirements.
Work through the procedure
Classify the source PDF
Check whether representative text can be selected and searched, then inspect which pages are scans. Record mixed content and other agreed features such as annotations. A filename ending in PDF is not enough information to choose a reliable test or infer extraction coverage.
Run comparable document variants
Process each version through the same agreed provider path and policy. Record whether the system accepts, rejects, flags or modifies it. If OCR is outside the supported workflow, evaluate the required user restriction rather than expecting a scanned fixture to be recognized.
Check removal beyond appearance
Inspect sanitized outputs where available using a PDF viewer and an approved text-extraction method. Search for the synthetic protected values and review the affected pages. If these inspection methods disagree, stop the conclusion and investigate the output representation with engineering.
Review degraded and mixed cases
Add a controlled lower-quality scan only if it reflects a genuine requirement. Check the mixed PDF page by page and inspect allowed content for readability. Record failure handling separately from detection quality so an honest rejection is not mistaken for a missed scan.
What to check before proceeding
1. PDF structure coverage
- Ready when
- Text, scanned and mixed variants each have a documented result matching the agreed scope.
- If the check fails
- Restrict the unsupported class or add a separate approved preparation workflow.
2. Recoverable content
- Ready when
- Agreed protected fixtures are absent from the inspected visible and extractable output content.
- If the check fails
- Do not share the output; investigate incomplete removal or an insufficient verification method.
3. Readable retained content
- Ready when
- Permitted sections remain legible and preserve the relationships needed for the summary.
- If the check fails
- Revise the fixture preparation or choose a more suitable document source.
Common mistakes to avoid
- Assuming the ability to redact a text PDF establishes OCR coverage for every scanned page.
- Checking that a name is visually obscured without testing whether it remains selectable or searchable.
Evaluate this workflow with Aona
Where Aona can help
Bring synthetic text and scanned examples to Aona and agree the currently supported PDF inspection and redaction behavior.
What to confirm
Do not infer OCR, annotation, attachment or image-layer coverage from a generic PDF-support statement; validate the required components.
Evaluating a control for your organization?
Bring your target AI tool, device and acceptance criteria. Review the supported control path, the evidence you need and any limitations before deciding on a pilot.