Which is the most suitable scanner resolution for documents? Detailing the answer given to the question raised by Professor George Nagy

Defining the correct image resolution is a fundamental issue to preserve all the information in a document, keeping the minimum image acquisition and processing times, as well as the storage space and computer bandwidth for network transmission, allowing for best-quality information extraction and automatic transcription. How exactly to find it? That important question was recently raised by Professor George Nagy, one of the pioneer researchers in Document Engineering. That fundamental problem in document engineering was never properly addressed. The digitalization standards and recommendations widely adopted today are based on "experimental evidences". This paper presents an answer to such an important question, based on the Nyquist-Shannon theorem from Information Theory.