How to OCR a PDF
Select your PDF
Choose the scanned or image-based PDF you want to process.
Start OCR
Send the document to the real OCR processing service.
Download the result
When OCR completes successfully, download the processed searchable PDF.
What is OCR?
Optical character recognition is a technology that analyses an image of printed or handwritten-looking characters and attempts to identify the text. In a PDF, OCR can be used to add searchable text information to pages that otherwise contain only images.
Why use OCR on a scanned PDF?
- Search for words or phrases inside a scanned document.
- Select recognised text for copying where the OCR engine supports it.
- Make archived scans easier to find and work with.
- Help move information from image-based documents into other document workflows.
Scanned PDF vs text PDF
A text-based PDF normally contains characters that a PDF viewer can search or select. A scanned PDF may contain only a picture of each page. OCR attempts to bridge that gap by recognising characters and creating a machine-readable text layer.
OCR accuracy and limitations
OCR is recognition, not a guarantee of perfect transcription. Accuracy can be affected by image resolution, skew, blur, shadows, folds, unusual fonts, handwriting, tables, low contrast and the quality of the original scan. Always review important OCR output.
Tips for better OCR results
- Use a clear, high-resolution scan where possible.
- Avoid heavily blurred or severely distorted pages.
- Keep pages as straight as possible.
- Good contrast between text and background generally helps recognition.
- Check names, numbers, dates and other critical information manually.
Privacy and file handling
Only make storage, deletion and retention claims that match the deployed Docelora processing system. Avoid uploading confidential documents unless the service's current published data-handling terms are appropriate for your use.
Troubleshooting
The PDF already has selectable text
OCR may not be necessary when the document already contains a reliable text layer. Re-OCR can sometimes change the document and should be used for a clear purpose.
The recognised text is inaccurate
Check the original scan quality. Low resolution, blur, skew, unusual fonts and complex layouts can reduce recognition accuracy.
Some pages are not searchable
OCR engines can encounter pages with poor image quality or unsupported content. Review the result and, if possible, improve the source scan before processing it again.
OCR processing fails
A damaged PDF, unsupported document, resource limit or temporary service error can prevent processing. Try opening the PDF and saving a fresh copy.
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Frequently asked questions
What does OCR mean?
OCR stands for optical character recognition. It identifies characters in page images and creates machine-readable text from them.
Can OCR make a scanned PDF searchable?
Yes, an OCR process can add a searchable text layer to a scanned PDF when the processing engine supports that output.
Will OCR make every word accurate?
No. Recognition quality depends on the source document and OCR engine. Important results should be reviewed.
Can OCR recognise handwriting?
Handwriting is generally more difficult than clear printed text. Whether handwriting is supported depends on the OCR engine.
Will the original page image remain?
An OCR workflow can retain the visual page while adding recognised text as a layer, but the exact output depends on the processing engine.
Can I copy text after OCR?
If the OCR engine creates a selectable text layer, recognised text can generally be selected or searched in a compatible PDF viewer.
Does OCR work with tables?
Tables and complex layouts can be difficult for OCR. Recognition may require manual checking or further formatting.
Can I OCR a password-protected PDF?
Encrypted or password-protected PDFs may need to be opened or unlocked before OCR, depending on the processing service.
How long does OCR take?
Processing time depends on document size, page count, image quality and server workload. The tool should show an honest processing state.