When pages of text are scanned the computer image that is created is not 'text'. It produces an image of text. To make this type of document accessible you would have to re-type the entire contents of the image, which defeats the purpose of scanning the page in the first place. There is a process to turn the image of text into actual text called Optical Character Recognition (OCR). When a page undergoes the OCR process the computer attempts to match the image it sees with a letter or symbol that it knows and it rebuilds the image of a text document into an actual document. This process is not always 100% though and usually requires some amount of human intervention to make it acceptable. Factors that affect the OCR process include:
When creating PDF's from printed source material follow this set of guidelines:
Even after the OCR process has been completed the PDF will still have to be verified for accuracy and reading order.
Many people want to convert their Word documents into PDF's. Word documents make good PDF's if certain rules are followed:
It is easier to make the necessary repairs in Word than it is to make the repairs in Acrobat after the PDF has been created. Save time and frustration and build the document correctly the first time. For a guide on how to make documents more accessible in Word view this Word document.