Lettering is the least discussed craft in comics and the one most capable of ruining a page. Readers do not admire good lettering; they simply read the page in the right order at a comfortable speed. When it is bad, they read the second balloon first, lose track of who is speaking, or give up on a paragraph set too small, and they blame the story.
It is also the part most often left until the end and fitted into whatever space remains, which is exactly the wrong order and the source of most of the problems.
Balloons control reading order
The eye follows balloons through a panel in a predictable path, and that path can conflict with the visual composition. Where they disagree, the reader hesitates. Placing balloons so they lead the eye along the same route the picture wants is what makes a page read smoothly.
This is why lettering must be planned during layout, as noted in the piece on panel rhythm. A panel composed edge to edge leaves nowhere for a balloon except across a face, and by then the choice has already been made.
Size is decided by the smallest screen
Text sized comfortably for a printed page becomes unreadable on a phone, and most readers are on a phone, which is the reading situation described in the piece on one-thumb readers. The practical rule is to letter for the smallest expected reproduction and let it be slightly large everywhere else.
Testing is the only reliable check. View the page at actual phone width, not zoomed, and read it. Almost every letterer discovers their text is too small the first time they do this properly.
Tails identify the speaker
A balloon's tail should point clearly at its speaker, and readers should never have to work out who is talking from position alone. Ambiguous tails are a common fault in two-character scenes where the figures are close together, which is most of this material.
Where a tail cannot reach clearly, the composition needs adjusting rather than the tail bending further. A tail that curves across half a panel to reach its speaker is a sign the balloon is in the wrong place.
Typeface and readability
Comic lettering typefaces exist because ordinary text faces read poorly in balloons at small sizes, particularly in all capitals, which most comics use. Line spacing, letter spacing and balloon padding all matter more than the choice of face itself.
Balloon shape should be simple and consistent, with enough internal padding that the text is not touching the outline. Crowded balloons read as cramped and slow, which affects the pace of the whole page.
Emphasis and when to use it
Bold within a balloon is how lettering carries stress, and it is the closest a comic gets to indicating how a line is said. Used on one or two words it works; used on several it stops meaning anything, which is the same hierarchy problem that affects every other kind of emphasis.
Different balloon shapes and outlines can indicate whispering, shouting, or a different medium, and these should be consistent across a work. Establishing the vocabulary early lets readers use it without being told.
Lettering and translation
Text length changes between languages, sometimes considerably, which is the edition problem described in the piece on re-editing for a market. Leaving more balloon room than the original language needs is the cheap insurance.
Keeping lettering on its own layer, separate from the artwork, is what makes any of this possible later. Text flattened into the image cannot be replaced without repainting what is underneath.
Vertical formats change several of these rules and are worth treating separately. A scrolling column has no page to arrange balloons across, so reading order becomes purely sequential and the main risk shifts to spacing: balloons too close together are read as a single block, and balloons too far apart introduce pauses nobody intended.
Making a page that reads in the right order
Plan balloon placement during layout, letter for the smallest screen, make tails unambiguous, keep balloons uncrowded, use emphasis sparingly, leave room for translation, and keep text on its own layer. None of it is visible when it works, which is the point.
Characters here are fictional and unmistakably adult, as set out in the reader agreement.