There are also some old papers, converted to PDF by way of dvips and Ghostscript, that are completely unreadable with a screen reader unless you OCR them, becau

There are also some old papers, converted to PDF by way of dvips and Ghostscript, that are completely unreadable with a screen reader unless you OCR them, because the text in the PDF is somehow not using Unicode or even ASCII. You'll see the same problem if you run pdftotext or similar on the document. My usual example is this: https://legacy.cs.indiana.edu/~dfried/mex.pdf https://legacy.cs.indiana.edu/~dfried/mex.pdf (I only know about this paper because someone linked to it on HN several years ago.) I'd be interested to know more about how the conversion to PDF ended up like this.