# PDF conversion preservation method

> Inspect the source-preservation contract, fixture coverage and the limits of local text extraction and OCR.

Canonical: https://pocketorbitnotes.app/research/pdf-conversion-method
Language: en-US
Published: not provided
Last updated: 2026-10-18

## Method, not a quality certificate

This page describes an inspectable conversion method. Hardware performance and recognition quality require independently reviewed results. No zero-case record or successful interface check establishes production readiness.

## Preservation contract

Hash the original before and after conversion. Render selected pages as PNGs, extract positioned text or recognize rendered images, record page number/method/review flags, and package relative references with checksummed assets. Import validates paths, file kinds, versions, expanded sizes and checksums before an atomic journal commit.

## Fixture matrix

Test digital text, image-only scans, mixed pages, rotation, columns, tables, diagrams, handwriting, equations, Unicode and each supported recognition language. Include password failure, malformed input, forms, annotations, resource limits, cancellation and retry. A failed page or unsupported form must be reported; retaining the original does not mean its transcription was successful.

## Record denominators and counterexamples

Record attempted, completed, failed, cancelled and skipped cases. Keep automatic preservation checks separate from independently reviewed extraction. Score omissions, reading order, negation, numbers/dates and recognition substitutions. OCR errors and generation errors belong to separate tasks. Publish the fixture/build/date and review count with any results.

## Network and engine boundaries

Browser workers, fonts and recognition data are served locally from the website origin; downloaded once for the session as required. Document bytes and passwords remain browser state. Apple parsing and Vision use device APIs. Review form/signature appearances against the unchanged PDF. Neither engine guarantees perfect layout, faithful mathematics or editable handwriting reconstruction.

## Related pages

- https://pocketorbitnotes.app/tools/pdf-to-markdown
- https://pocketorbitnotes.app/features/pdf-to-markdown-workspace
- https://pocketorbitnotes.app/learn/pdf-to-markdown-with-images
- https://pocketorbitnotes.app/help/import-pdf-into-workspace
- https://pocketorbitnotes.app/tools/markdown-inspector
- https://pocketorbitnotes.app/features/markdown-editor

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