Glyph design: the lowercase i

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The ‘i’ is a fairly simple letter, and relatively easy to design (unlike the ‘o’ which is simple but tricky to design well). Its stem is also found in no less than thirteen other letters. So ‘i’ is a pretty important letter.

Structure of the ‘i’

The ‘i’ consists of just a single vertical stem, and a dot called a tittle.

Components of a lowercase letter ‘i’

Stem

     The vertical stroke that makes up the body of the ‘i’.

Serifs

     The serifs are the most important part of the ‘i’, since they will be reused in so many other letters. The ‘i’s stem ends in an angled half-serif on top—called a unilateral serif—and a full serif on the bottom—called a bilateral serif since it extends out in both directions. Bilateral serifs are almost always flat to the baseline, and visually (but not mathematically) symmetrical. Unilateral serifs on the other hand are usually angled, usually to the stress of the typeface.

     In many typefaces (usually old styles and transitionals, but some didones too), the serifs are connected to the straight part of the stem by brackets. The brackets are just the smooth curves that link the serif protrusion with the stem.

Tittle

     The dot of the ‘i’. Yes, it's actually called a “tittle”.

Constructing the i

     The ‘i’ is all about serifs. I crudely traced the serif off of a Garamond ‘i’ to get the right proportions. If you want to make a serif from scratch, keep in mind that serifs are usually between half and the full width of a normal-weighted (not bold) stem.

     Bracketing the serif, while still trying to preserve the slope of the serif, and making it symmetrical (we’ll add asymmetry back in later) :

     Constructing the top serif:

     It's worth noting that the right side of the ‘i’s bilateral serif is usually very slightly shorter than its left side.

Connecting the two serifs to form the stem. Also it’s a good idea to make sure the stem is the same width as that of the ‘a’ :

The tittle of the ‘i’ is usually very simple. It's almost always a simple circle, though more calligraphic typefaces sometimes make it into a diamond shape.

Left to right: Garamond, Minion Pro, Warnock, Proforma, Linux Libertine, Liberation Serif, Bodoni

The tittle is typically about 20–30 percent wider than the stem of the ‘i’.

Left to right: Garamond, Minion Pro, and Bodoni

It’s also usually offset slightly to the left of the center of the stem, due to the unilateral serif on top of the ‘i’.

The tittle is generally displaced just under one tittle height above the top of the stem.

This tells us how to construct and place the tittle:

Also keep in mind that when matching its height to that of the other letters, the foot of the ‘i’ falls right on the baseline, but since the top is pointy, it has a bit of an overshoot.