Optical character recognition in PDF

Optical character recognition allows to convert images containing text to editable PDF text format, which supports document text search, copying, edition and all other PDF text functionality. Text recognition can be performed only if it is not locked in PDF document permissions.

To use optical character recognition choose Document -> OCR menu item. Set following parameters in the dialogue window:

Optical character recognition in PDF documents

  • Page Range Set pages where optical character recognition must be performed.
  • Languages Set language(s) of recognized text. In order to optimize text recognition quality, it is best to choose minimal number of languages.

If text recognition is used for the first time, languages list will be empty. To add languages, press Install languages button.

  • Install languages Check marks to choose required languages. Following window lists languages, which recognition is supported in Master PDF Editor.
  • Font Family Choose font family, which will be used in the document after the text is recognized. When choosing auto, the application will choose the most appropriate font family for current document.
  • Searchable Text If this option is chosen, recognized text will be available for search and copying only. It will be inserted into document as invisible layer under its image.
  • Editable Text With this option recognized text will be available for editing. The text will be inserted in front of the image that contains it. The image itself will be covered with background color.
  • Manually edit all recognized text If this option is chosen, a dialogue window for text edition will be opened during text recognition. It will display:
  • Original A piece of image with text. Automatically recognized text corresponding to the image.The dialogue window will successively show each part of the PDF document image with corresponding recognized text. This allows to edit text before inserting it into the document.



  • Yes Automatically recognized/edited text will be inserted into document. The dialogue window will display next image and corresponding text.
  • Yes to All All images will be automatically recognized and written into the document. This dialogue window won“t appear again during this recognition.
  • Not Text The image does not contain text. Cancel text insertion for current image.
  • Cancel Cancel text recognition.


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