I recently has a customer who requested a sign with 10" lettering. I thought that this would be easy just by using 720 point type size. Using 720 actually produced type of approximately 6" height. To achieve 10" high lettering required setting the font point size to 1040 points. Any ideas why?
Type size refers to the sizes of the slug that the type is built on. The baseline will be somewhere above the bottom of that slug, with descneders going below the baseline, and caps and ascenders going upward, but there are no rules or set amounts for how much of the total slug height will be used (and you can presume that there will always be at least some clearance at the top and bottom to prevent collisions between lines.