Why generic OCR isn’t enough for chromatography
Chromatography PDFs look like they should be OCR-friendly — and they are, for the prose. The trouble starts at the table.
The numerical-fidelity problem
OCR was trained on the world’s text — newspapers, books, forms. Chromatography reports use:
- 8-10 significant digits (e.g.
2,345,678peak areas) - Scientific notation (e.g.
1.234e+05) - Mixed decimal separators depending on locale (
5.234vs5,234) - Tight column spacing that confuses table reconstruction
Even the best generic OCR (ABBYY FineReader, Adobe Acrobat Pro) typically achieves 95-98% character accuracy on dense numerical tables. At 97% accuracy, an 83-page Empower report has 50+ wrong cells. In QC, that’s worse than manual entry — because the error rate is hidden.
The structure problem
A chromatography PDF isn’t just a table. It’s:
- A trace plot (image)
- A peak table (structured data, sometimes multi-page)
- System suitability metrics (separate small table)
- Sample / method headers (key-value text)
Generic OCR returns text. Reconstructing the four sections into the right relationship requires layout analysis tuned for chromatography report templates — which is exactly what ChromaParse does.
| Dimension | Generic OCR | ChromaParse |
|---|---|---|
| Numerical precision | 95-98% | >99.9% |
| Cross-page tables | Often fragments | Reconstructed correctly |
| Vendor recognition | None | Auto-detect Waters/Agilent/Thermo/Shimadzu |
| Source-trace | None | Per-cell page + bbox |
| Output format | Generic CSV/Excel | LIMS-ready, schema-validated |
Where generic OCR still fits
- Non-chromatography PDFs — invoices, forms, contracts. Use the right tool.
- Quick visual extraction — when you just need to read the values, not import them.
- Languages or scripts ChromaParse doesn’t yet support — generic OCR has broader script coverage if you need it.
When ChromaParse wins
If the PDF is a chromatography report from a supported vendor and you need the data structured, validated, and audit-traceable, generic OCR adds a verification burden that often outweighs its setup simplicity.