OWD
I don't know about your computer, but on mine in the upper right-hand corner of the screen is a small gear symbol, when you put your mouse pointer on it it says (Tools (Alt+X) click on it and among other things it opens up a zoom function. It's still not great, like you said it's a poor quality scan, but it's better enlarged 200%.
Steve

Approach life like you do a yellow light - RUN IT! (Gail T.)