You are probably trying to scan the document using optical character recognition (OCR)--don't do this. PDF can handle both text and scanned documents. It can also take scanned documents and perform OCR on them, turning the image back into editable text. However, this process has many problems and should not be done before e-filing them. It is permissible to perform OCR on PDF documents after they are in the e-filing system, since any OCR errors will not be placed in the official documents at the court.