Type on a curve, and why it splays

What the software is actually doing

Type on a path is positioned by arc length along the baseline. The engine walks the path, placing each glyph’s origin at the distance the previous glyph’s advance width demands, and rotates the glyph to the path’s tangent at that point.

Every problem with curved type follows from one fact: the glyph has height, and the baseline does not.

On a circle of radius r, the baseline has circumference 2πr. The top of a capital, at cap height h above the baseline, sits on a circle of circumference 2π(r+h). Those two circles have different lengths, but the letter is rigid. So:

• Text on the outside of a curve splays: the tops of the letters are pulled apart, the bottoms crowd together.
• Text on the inside does the reverse: the tops jam, the bottoms fan out.

The tighter the radius relative to the cap height, the worse it is. This is not a bug and no setting fixes it.

The four things that do help

1. Increase the radius. The ratio that matters is cap height to radius. At r = 20× cap height the splay is barely visible; at r = 3× it is unusable.
2. Add tracking. Splay is most obvious when letters nearly touch at the bottom. Open the whole line by 30 to 80 thousandths of an em and the crowding disappears; the top-heavy look remains but stops mattering.
3. Choose the face. A typeface with short capitals relative to its width (a wide, low grotesque) splays less than a tall condensed one, because h is smaller relative to the advance width.
4. Outline and adjust individually. For a badge that must be right, convert to curves and rotate each letter about its own optical centre. Twenty minutes, and it is the reason good circular badges look good.

Baseline shift, which is the control people miss

Type sits on the path by default. Baseline shift moves it up or down relative to the path without changing the path.

• Illustrator: Character panel, the A↕ field, or Alt+Shift+Up/Down.
• Inkscape: Text and Font dialog, or select the characters and use the vertical-shift field on the text toolbar.
• CorelDRAW: the Distance from path field on the property bar when text is fitted to a path.

Use it to lift text off a circle so the letters’ descenders clear it, or to push text inside a ring.

The bottom of a circular badge

The classic problem: text on the bottom half of a circle reads upside down.

The fix is not to flip the text. It is to draw a second circle, in the opposite direction, and set the bottom text on that one.

1. Draw circle A, clockwise. Put the top text on it.
2. Duplicate it, reverse its direction (Inkscape: Shift+R; Illustrator: Attributes ▸ Reverse Path Direction), and make it slightly smaller so the two lines of text sit at the same visual distance from the centre, because the bottom text will hang below its baseline while the top text sits above.
3. Put the bottom text on circle B and set it to align centred at the 6 o’clock position.

Hide both circles by setting their stroke and fill to none. They stay in the file and the text stays live.

Moving text along the path

Every implementation gives you a bracket or handle you drag to move the start point, and dragging it across the path flips the text to the other side. That flip is the source of most “my text suddenly went inside the circle” confusion. In Illustrator the handle is the small perpendicular bar at the start of the text; double-clicking it opens Type on a Path Options, which has Align to path: Ascender / Descender / Centre / Baseline and an Effect dropdown with Rainbow, Skew, 3D Ribbon, Stair Step and Gravity. Rainbow is the default and the only one you usually want.

What to do before sending it anywhere

Convert to curves, and check the shape of every letter afterwards. Some text engines apply the rotation at render time in a way that does not survive export cleanly, and CorelDRAW in particular has historically produced slightly different spacing on curved text between the on-screen view and the PDF. Outline it, look at it, then send it.