> Doesn't that nice layout suggest there is some sort of 'cap height' value at play which then allows those vertical lines to work together so well? The em siz

> Doesn't that nice layout suggest there is some sort of 'cap height' value at play which then allows those vertical lines to work together so well? The em size? The thing the article is suggesting is worse than cap height? > Edit: The way I see 'cap height' is it is some sort of maximum guaranteed value. Now it turns out for English all capitals will have that exact same maximum value. No, it's not a maximum guaranteed value, it's the height of capital letters. In a Latin font, the ascenders of lower-case letters exceed it. This is exactly where my difficulty is: some Arabic letters have ascenders and descenders. Depending on the font, it may or may not have a baseline. Letters that don't have ascenders and descenders have a height which I would say corresponds roughly to the x-height. The one thing that I can't see any correspondence to is the height of capital letters!