Learn how PDF OCR works, when to use it, how to improve scan quality, and what to check after recognizing text.
A scanned PDF may look like text, but to a computer it can be only an image. You can read it, but you cannot search it, select it, copy it, or extract it reliably. OCR changes that.
PDF OCR recognizes text inside scanned pages and adds a machine-readable text layer. That makes documents easier to search, archive, quote, translate, and convert.
Use OCR when:
If text is already selectable, OCR may not be necessary.
OCR accuracy depends heavily on image quality.
Better OCR comes from:
Blurry scans produce bad recognition. OCR cannot perfectly recover text that the image does not clearly show.
Sideways or upside-down pages reduce accuracy. Use before OCR when pages are not upright.
Also check mixed documents. One page may be upright while another is sideways.
After OCR, test search.
Search for:
If search works, the text layer exists. If search fails, OCR may not have applied correctly or the recognition quality may be poor.
OCR makes text extractable, but it does not always recreate perfect document structure.
Expect issues with:
Use PDF to Word after OCR if you need an editable document, then review carefully.
Scanned PDFs often contain sensitive data:
Use OCR tools you trust. If the document is sensitive, remove unnecessary pages and consider redaction before sharing.
For sensitive sharing, use PDF Redact and verify the result.
Using poor scans. Better source images improve output.
Skipping review. OCR can misread characters.
Trusting tables blindly. Table structure often needs cleanup.
Forgetting language settings. Recognition depends on language.
Assuming OCR removes images. It usually adds text; the scanned image remains.
OCR turns scanned documents into searchable text, but quality depends on the scan and review. Prepare pages first, run OCR, test search, and verify important text manually.
Readable to humans is not the same as readable to software. OCR bridges that gap.
Akousa