File > Page Setup = Scale
100% is usually best

If you have a mouse with a scroll wheel hold down the ctrl key and rotate the wheel. It should remember the font size when you reopen the window.

Thank you! It worked.

The proposed cure merely changes the size on the screen. The actual prints still come out with a very large font. I agree initial post this is a ridiculous problem that has spoiled Firefox as a very credible browser. Please Help us.

The answer that I posted on the 15th is the fix for "print" font size. The reponse from marcbgrmi was for changing the page or text zoom level on the "screen", which has no effect on printed pages.