A counter is the enclosed or partly enclosed space inside a letterform. In letters such as a, o, and d, that interior white space is part of the letter’s shape—not leftover room. section 5.2.1
Counter shape strongly affects readability at small sizes. More rounded counters are usually easier to read because they preserve useful white space; tightly squished counters can nearly disappear. section 5.2.1
When comparing fonts for readable text, check:
- Whether counters remain open and visibly spacious at the intended size. section 5.2.1
- Whether the counters are reasonably rounded rather than compressed or overly narrow. section 5.2.1
- How counter shape works alongside x-height and font weight; no single yardstick decides readability. section 5.2.1
A practical comparison
Compare the same paragraph in several fonts at a small size. Museo Moderno’s counters are described as the roundest of the comparison, while Brush Script MT’s are so squished that they are nearly nonexistent—an amusingly effective warning against using it for text blocks. section 5.2.1
Figure 5.10 The shape of the counter, or the space inside closed or partially closed letters (colored red here), affects readability. Generally, more round = more readable.
Use the counter-shape comparison to see how the interior spaces of letters affect readability, especially at small sizes. section 5.2.1
