Typewriter ribbons that were 2 colours were always black and red. (I presume that was a carry over from when your main ink would have been black or possibly blu

Typewriter ribbons that were 2 colours were always black and red. (I presume that was a carry over from when your main ink would have been black or possibly blue, and the alternative would have been red). As your normal credit entries would have been black, if the "bottom line", the sum of your accounting book column was negative, showing a loss, you would emphasize it with the red type.