Non-Designer’s Type Book, The, Second Edition

Chapter 15. Linespacing (leading)

Linespacing is the space between the lines of type. When type was set in metal (which wasn’t that long ago), compositors would insert thin strips of lead (yes, the metal called lead) between the lines of metal characters, which is why the space is called “ledding,” not “leeding.” Leading is measured in points, just like type. The measuring system works like this:

So now if you look at a type specification that calls for 10/16, you instantly know there is a lot of space between the lines. If you see type that is set with the same number for the leading value as for the type size, such as 24/24, which is called ...