In the past ten document conversions I did, attorneys shelled out frustrations: OCR output was messy, irrelevant text …
Open the scanned PDF in Adobe Acrobat.
Check if the document is an image-only PDF by attempting to select or search for text.
NoteOCR cannot recognize text if the PDF does not contain images or if the text is already selectable.
Go to Tools and select Recognize Text.
Click Recognize Text and choose In This File.
Review the OCR output for errors or missed text by scrolling through the document.
If OCR accuracy is poor, check the scan quality: ensure the document is at least 300 dpi, not skewed, and has high contrast.
Best practiceLow-resolution, blurry, or skewed scans are the most common causes of OCR failure.
Rescan the original document at 300 dpi or higher, using RGB mode for discolored or older pages.
Best practiceFor best results, avoid scanning with excessive brightness and ensure pages are flat and unmarked.
Repeat the OCR process on the improved scan.
Manually correct any remaining OCR errors by clicking on suspect words to edit and accept corrections directly.
NoteYou can click on suspect words to edit and accept corrections directly.
Save the corrected PDF.
If OCR still fails, try rescanning your document at a higher resolution and check for skewed or blurry pages before running OCR again.
This runs in the Acrobat app - there is no separate API for this task.
| Feature | Image-only PDF | Searchable PDF (after OCR) |
|---|---|---|
| Text Interaction | Cannot select, copy, or search text. | Can select, copy, and search text. |
| Content Type | The document is seen as one big picture. | Has a hidden layer of real text over the image. |
| Use Case | Good for viewing documents as they were originally scanned. | Good for editing, archiving, and finding specific information. |
Acrobat's 'Recognize Text' feature is designed for pages that are only images. If a page already has real, selectable text, Acrobat will show this message. It means the page doesn't need OCR because it's not an image-only page. You should only use this feature on scanned pages that are pictures.
If your scanned document is blurry or has low quality, the 'Recognize Text' feature might not work well. OCR relies on clear images to accurately identify characters. For the best results, ensure your original scan is clear and at a high resolution (like 300 dpi). If the text is very unclear, even OCR might struggle to make it perfectly searchable. You may need to rescan the document if possible.
Yes, you can use the Adobe PDF Services API to automate OCR for multiple documents. The 'OCR PDF' operation allows you to send PDF files to a specific endpoint. This is useful for large batches of scans that need to be made searchable for archiving or indexing. You can integrate this into your own applications.