Poster Lettering: Compare Letterforms and Spacing

Make the message readable through letterform and spacing

A poster heading can fail even when every word is present. Neighbouring strokes may merge, enclosed spaces may close, or the letters may be so stylised that the reader has to guess the message. This lesson focuses on those lettering decisions through three original studies for a fictional seed-swap notice.

The task is to preserve the exact words while revising letter structure, spacing and a simple size hierarchy. It does not require a page-layout application. Use the measured drawn letters as a paper comparison, and check any eventual poster at its intended physical size and reading distance.

The complete message stays fixed

Heading: SEED SWAP

Supporting line: Bring labelled seed packets

Event line: Saturday, 10 am · Garden room

These are fictional teaching details, not an announcement of a real event. Read the heading first, followed by what to bring and then the time and place. Do not “solve” crowding by dropping a letter, shortening the location without permission, or deleting the supporting instruction.

Use the right term for the problem

A serif is a short finishing stroke at the end of a main letter stroke. A sans-serif design lacks those serifs. Neither category guarantees readability. The actual forms, spacing, size, reproduction and reader’s circumstances matter. The two capital I constructions below isolate the structural difference rather than ranking one as universally better.

A counter is an enclosed or partly enclosed internal space, such as the enclosed area in D or P. A baseline aligns letters along a line; cap height describes the height of capital letters above that baseline. Kerning adjusts the spacing of a particular character pair. Tracking adjusts spacing across a selected run of characters. Word spacing separates words. Leading is the baseline-to-baseline distance between lines, not merely the blank gap visible between their nearest strokes.

Worked case 1: repair compressed lettering

Study A puts each capital in a nominal 12-unit-wide, 20-unit-high design box and advances the next letter by 12 units. This leaves no clear horizontal gap between adjacent boxes. Vertical strokes of neighbouring letters can meet or appear to form a single shape, especially in the repeated E pair.

Study C keeps each letter’s size but increases the advance to 16 units, producing a 4-unit box gap. The main change is tracking across the heading. “SEED” now spans 60 units: four 12-unit boxes plus three 4-unit gaps. That arithmetic describes the construction, not a guarantee that all letter pairs will look equally spaced.

After opening the overall spacing, inspect each pair optically. A sloping A and a vertical P leave a different-shaped space from two vertical E stems. A small pair adjustment may help even when bounding-box gaps match. Do not stretch the letters horizontally merely to fill the extra space; that would change their proportions as well as their spacing.

Worked case 2: restore the counters

Study B uses the wider advance but fills the counters of D and P. The surrounding spacing is now generous, yet the letterforms remain hard to distinguish. This shows why tracking alone cannot repair every legibility problem. The intended heading is still SEED SWAP, but the damaged letters ask the viewer to infer rather than read their forms.

The targeted repair reopens the internal spaces while retaining the external shape, cap height and letter positions. In the repaired D, the long left stem connects to a rounded-looking angular bowl, enclosing a visible space. In P, the smaller upper bowl has its own counter, with a stem extending below it.

For a small reproduction, inspect whether these spaces remain open after output. A gap visible at high zoom can disappear in a reduced copy or rough print. Increasing the counter opening or simplifying the stroke may be more useful than making the heading decorative. Judge the actual result, not the letter’s name alone.

Worked case 3: retain a two-level hierarchy

Study C gives the heading a drawn cap height of 40 illustration units and keeps the two supporting lines smaller. The larger title identifies the event, while the instruction and event details remain separate, readable lines. Hierarchy concerns their relative prominence; the supporting information must not become expendable.

In the diagram, the two supporting baselines are 29 units apart. Their visible gap is smaller because the letters occupy space above and sometimes below a baseline. If you change the supporting typeface or size, preserve useful separation by checking the actual forms again rather than blindly retaining an old gap value.

No universal minimum point size follows from this illustration. A corridor poster seen from several metres and a handout read closely have different demands. Compare a full-size proof under the intended viewing conditions. Ask a reader to report the words, not merely whether the poster looks attractive. Any misreading identifies a practical revision target.

Three fresh repair tasks, with solutions

1. One bad pair. Most of SWAP looks evenly spaced, but WA looks too wide. Should you tighten the entire heading? Solution: first adjust that specific pair, which is a kerning decision. Global tracking would also tighten the pairs that already work. Recheck the whole word after the local change.
2. A four-letter measurement. Four 12-unit letters use a 3-unit gap between neighbouring boxes. What is their span? Solution: 4 × 12 + 3 × 3 = 57 units. There are three internal gaps, not four. This measurement excludes any separate word space after the word.
3. Clear heading, crowded details. The title reads correctly, but the supporting instruction touches the event line. Which variable needs attention? Solution: revise the leading between those lines and inspect their tallest and lowest strokes. Altering the title’s kerning would not separate the two supporting lines.

Record a justified selection

A strong selection statement says what became easier to read and why: “I chose C because its open D and P counters retain distinct letterforms, while the 4-unit nominal gaps separate neighbouring letters. The larger heading establishes priority, and the two smaller lines preserve the practical details.” This is more useful than calling the lettering modern, beautiful or professional without pointing to evidence.

Frequently asked questions

Does serif lettering always read better?

No. Serif describes a structural feature, not a guaranteed outcome. Test the specific forms and spacing at the intended size and viewing distance.

Is kerning the space between words?

No. Kerning adjusts a particular character pair. Word spacing is the gap separating words, while tracking changes spacing across a selected run of characters.

Why are equal measured gaps not always optically equal?

Letter outlines enclose differently shaped spaces. Sloping and curved strokes can make equal bounding-box gaps look uneven, so a measured plan still needs visual checking.

Can wider tracking repair a closed counter?

No. Tracking separates neighbouring characters. A closed counter is an internal letterform problem and needs a change within the affected character.

Is leading the same as cap height?

No. Cap height measures capital-letter height; leading measures the distance between consecutive baselines. Both influence the resulting line separation.

May I remove details to make the heading fit?

Not in this exercise. The message is fixed. Revise lettering, spacing or the arrangement while retaining the supporting instruction, time and place.

Do the diagram units prescribe a universal poster size?

No. They make the comparison reproducible. A real poster requires proofing at its intended size, reproduction method and reading distance.

References for the ideas

Adobe’s Understanding typography concepts supports the distinctions among serif, leading, kerning and tracking. The lettering studies and all tasks are original.