A text highlighted in dark grey contains illegal Unicode characters and therefore can not be included in the comparison.
Sometimes, after the conversion or creation process of a pdf file, parts of a text may be recognized as illegal characters, that means, it contains unsupported or missing Unicode characters. When that happens, this text will be highlighted in dark grey and TVT will not be able to read the text.
This can have different reasons like the conversion process from the layout file to PDF , unsupported fonts or software.
To check if the document you are working on contains unsupported or illegal characters, open your file using Adobe Reader, copy the section of the text that has been highlighted in grey by TVT and then paste it to Word or Notepad. The text may look as follows:
If you use Polyhexanide with other eye drops
Do not □□□ Polyh□xanide with □□□□□ eye drops. Wait minimum 24 hours before you use other eye drops. If you want to use Polyhexanide �fter you used other eye dr�ps, wait at least 12 hours before using Polyh�xanide.
If that is the case, request a new pdf file, as the □ and the � are the symbols used in Unicode to replace missing, unsupported, invalid or unrecognizable characters.
Do you want to learn why TVT uses the Unicode Standard as all modern software providers? Check the Unicode article on our blog.