I am trying to write a document that can only be read by humans. The document content can't be copied. For that purpose, I am converting its pages to pictures and adding them back to a PDF file. The main issue is that any OCR program can get back the whole written text, especially that the page is going to be clear (as opposed to a scanned book) which will increase the OCR accuracy.

So, is there a font that can't be recognized by an OCR. Otherwise, is there a technique that will make my document only readable by humans, yet unrecognised by an OCR? (for instance, adding a specific background, etc...)

Thank you in advance.