... For the reason that IBM made their 1928 card with 80 columns, in an attempt to increase the storage efficiency of Hollerith’s 45-column card without increasing its size?
That said, ~60 characters per printed line has been the typographer’s recommendation for much longer. Which is why typographers dislike Times and derivatives when used on normal-sized single-column pages, as that typeface was made to squeeze more characters into narrow newspaper columns (it’s in the name).
That said, ~60 characters per printed line has been the typographer’s recommendation for much longer. Which is why typographers dislike Times and derivatives when used on normal-sized single-column pages, as that typeface was made to squeeze more characters into narrow newspaper columns (it’s in the name).