1. Proportions
Futura and Garamond have almost identical vertical metrics — the relationship of lowercase and uppercase letters (x-height) and the length of extenders. The moderate height of the lowercase letters along with the height of the ascenders give, in addition to a feeling of “slimness,” a sense of space between lines even where there is little leading.
The capitals of both typefaces use the classical proportions of Roman capital letters, each letter of which derives from a simple geometric form: triangle, circle, square (or one of their segments). The drawing of this kind of face is rhythmically complex. The “voice” is never monotonous.
Garamond's lowercase letters are noticeably different in width, a feature deriving in part from the not quite extinguished link to the proportions of humanist minuscule, the basis for the first serif typefaces of the 15th–16th centuries, which were much influenced by Renaissance ideas of “beautiful form”. Odd as it may seem, the proportions of the lowercase letters of Futura, a face of quite a different time and character, are very close to those of Garamond. But, for Futura, a typeface meant to last long after the era of its creation, use of the time-tested classical proportions was entirely natural and wise.
2. Details
Like many other handwriting-based Renaissance serifs transformed by the chisel into type, the letters of Garamond have a direct, expressive link to their origin in script.
On the other hand, Futura is one of the first typefaces whose letters are based on the idea of “pure” geometry. But Futura's geometry is a matter more of the eye than
of mathematics — a geometry created with compass and ruler but adjusted countless times before reaching final typographic acceptability.