User Guide
Nitro PDF Pro
Scanning and OCR

Troubleshoot OCR

The results of Optical Character Recognition (OCR) are somewhat dependent on the quality of the electronic document, so here are some tips to help you improve OCR results:

  • Set the scanner color settings to Grayscale, or Black and White if the text is black against a white background
  • If supported by your scanner, adjust brightness and contrast to achieve deep blacks and bright whites
  • Set the scan quality (resolution) to 300dpi or better
  • Start with a good original document. Wrinkles and creases might hinder OCR accuracy
  • Ensure scanner glass is clean and free from smudges
  • Keep your pages as straight as possible during scanning. Skewed pages require more processing in the OCR engine
  • Depending on the quality of your scanner, you might need to attempt several scans of the same document to process the best resulting image
  • If your text is on a patterned or colored background, try to obtain another version on a plain white background. Text against colored backgrounds or gradients will require several attempts with different settings until the right configuration for successful OCR is found
  • Some smudges can be manually repaired by using white correction fluid to cover unwanted artifacts
  • If supported by your scanner, enable the despeckle setting to remove noise from your image
  • If supported by your scanner, increase text smoothing to remove harsh blends and grain
User Guide