On some keyboards, if you hold down the "control" key and press the "=" key at the same time, the print will get bigger.
If you hold down the "control" key and press the "-" key, the print will get smaller.
On the Mac, I need to press the key that has the apple on it (I think it's the ALT key) and the = key to enlarge, and the apple (alt) key and - key to reduce the image.