How can I scan a document without losing the original quality?

I am scanning in pages from an old book so that I can recreate the font of this book, but the letters are pretty small and if I scan them in at 150 or 300 dpi I won't get the details needed to recreate this font, and a higher dpi with more details will be too large and my computer will crash. So 1: How were books scanned and reprinted in (let's say) the 80's, that the prints have not lost quality with scanning (sure the letters are a bit smudged, but they aren't low resolution). So if I need to scan and retain the original quality, that seems to be my best shot, but how is that done? And 2: Is

Question by Zjamkeh on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.