Font design is full of necessary optical illusions! Have you ever noticed that a circle that is the same height as a square looks smaller when they are placed next to each other?
If the vertical extremes of your round characters (all of them – not just o, O, and zero) align exactly to your font’s baseline and x-height or cap-height, they will look too small next to the font’s other characters, and the text will look irregular.
Rounded characters should “overshoot” all of these internal font measurement guidelines. The exact size of these overshoots, however, is somewhat dependent on what style of font you are drawing, and what its intended point-size is. As a type designer, you’ll need to learn to regulate these things by eye. This same principle also applies to the points of the A and V.
- Making Geometric Type Work – Ian Moore’s reminder to trust your eye more than the grid.
- Typeface Mechanics 001 – Why you need overshoots. Tobias Frere-Jones examines the surprising puzzle of making sizes and alignments visually equal.
- Typeface Mechanics 002 – Tobias Frere-Jones on managing degrees of weight
- Optical illusions – the “bone effect” and other phenomena, explained by G. Briem
- I Love Typography - Inconspicuous vertical metrics - Overshoots and vertical metrics