I learned something really cool about type today via this article about inconspicuous vertical metrics. Since most of the things we read on the 'net are size 10 Arial, it's not uncommon to overlook the minute details in the typefaces we see daily.
Vertical metrics are used to gauge the heights of various aspects of a font. There are five vertical metrics that are commonly used, and over a dozen that are more obscure. All of these measurements are used to make the typeface more clear, uniform, and pleasing to the eyes.
My favorite inconspicuous metric from the article is the overshoot because it's based on the optical illusion of rounded sides. The idea is, if letters with rounded tops or bottoms had the exact same caps height or baseline as the other letters, they would appear smaller than other characters. This vertical difference is not apparent at normal (small) font sizes, but the disparity is obvious when the type is enlarged.
Since each character has unique edges and curves, typefaces must compensate for the optical illusions created by the diverse shapes. Did you know that the horizontal bars on the capital A, H, E and F are all different heights? Or that each upper curve of the capital R, P, and B has its unique shape?
Read more about these and other cool metrics and how they are used in font design at iLT. I now have a new appreciation for the thought and details that go into making our typefaces!
- i love typography, a fantastic blog for the type enthusiast