Softening letters with corner rounding in Font by Zaweba

Sharp corners make letters look precise and a little formal. Round them off and the same alphabet turns friendly, approachable and soft. That's why rounded lettering turns up on toys, sweets, signs in children's libraries and a lot of informal branding.

Corner rounding in Font by Zaweba is one of the operations in the style stack. It has two sliders rather than one: an outer radius and an inner radius, each from 0 to 200 font units. Font units are the measurement every font uses internally, and this app works at 1000 units to the em, so a radius of 200 is a fifth of the full height of the em. That's a lot of rounding, enough to make shapes noticeably blobby. Smaller values give a gentle softening that people feel rather than notice.

Outer and inner corners

An outer corner is one that points outwards, like the top corners of a capital T or the bottom corners of an L. An inner corner points inwards, like the place where the arm of an L meets its stem. They behave differently when you round them, which is why they have separate sliders.

Rounding the outer corners is what makes letters look soft from a distance. Rounding the inner corners fills in the sharp notches where strokes meet, which makes joins look smooth and slightly inflated. A common approach is to round outer corners more than inner ones. Too much inner rounding at a heavy weight can start to fill in small spaces, especially in letters with tight joins such as k, x and the middle of M and W.

Starting from the Rounded preset

If you want a rounded font quickly, the Rounded preset is the easy way in. Choosing a preset sets up the style stack for you, and from there every slider is still yours to adjust. You can turn the rounding up or down, change the weight, add a decoration, or switch off operations you don't want. Nothing about a preset is locked.

You can also add rounding on top of any other look. A slab serif with a little rounding loses its hard edges and feels more like signwriting. A stencil font with rounded corners reads as friendlier and less military.

Getting the amount right

Rounding interacts strongly with weight. On a light font there are very few square corners to round, because the strokes are thin, so even a large radius may barely show. On a heavy font the corners are big and the effect is obvious. Set the weight you want first, then bring the rounding up.

Look at the small sizes in the live preview's waterfall too. Soft corners that look charming at 200 can make small text look slightly blurred, as if it were printed on absorbent paper. For a font meant for worksheets or signs that will be read close up, moderate rounding is usually kinder than heavy rounding.

How it works with serifs and components

Because the stack is ordered, it matters where rounding sits relative to serifs, decorations and cut-outs. Every operation can be moved up or down. Try the rounding before and after the serif step and watch what changes in the preview: you may find one order gives smooth, soft serifs and the other keeps the serifs crisp while rounding only the letters. There's no right answer, only the look you want.

Cut-outs such as the round hole or the notch are subtracted from the letters, and outlines turn letters hollow. Both are affected by how round the outer shape is, so if you use them, check a few letters closely after changing the radius.

Small mistakes to watch for

Rounding a font heavily and then judging it only on capitals is a common trap. Lowercase letters have smaller parts, and the same radius takes a bigger bite out of them. Look at words like "minimum" and "kick", which have plenty of joins and stem ends. If a hand edited letter looks different from its neighbours after rounding, check it in the glyph editor, since edits made in Outline mode don't follow the skeleton the same way.

Corner rounding is a quiet setting, but it does a lot for the personality of a typeface. Small amounts make a font approachable without making it childish, and Font by Zaweba lets you find that balance with two sliders and a preview.