Kerning and Tracking

Kerning is the adjustment of space between one specific pair of letters. Tracking, also called letterspacing, is a uniform adjustment applied across a whole run of text. The distinction is between a local correction and a global setting. Kerning exists because letters have different shapes: an uppercase A next to a V leans toward it and needs less space, while an uppercase H next to an I already has two vertical strokes and needs more. A typeface ships with a kerning table listing hundreds or thousands of such pair adjustments, applied automatically. Tracking, by contrast, is a decision the designer makes about the overall density of a setting, and it applies indiscriminately to every gap.

Both exist to produce even typographic color — the uniform gray a well-set paragraph shows when you unfocus your eyes. The eye judges the space between letters by area, not by distance, so a mechanically equal gap between every pair looks visibly uneven. Kerning corrects for that perceptual fact. Tracking exists because a typeface's built-in spacing is tuned for one situation, usually mid-sized text, and other situations need a different density. Large display sizes look loose at default spacing and need negative tracking; uppercase runs and very small text look cramped and need positive tracking. Neither adjustment invents anything; both compensate for a fixed design meeting a variable use.

• →The pairs AV, To, Yo and LT, which almost always need kerning because their shapes create or close visual gaps.
• →A logotype, where each pair is usually kerned by hand because it will be seen thousands of times at one fixed relationship.
• →An all-caps label or small heading, where slight positive tracking restores the breathing room capitals need.
• →A ninety-point headline, where negative tracking pulls the word into a single readable shape rather than a row of letters.

The word kern comes from metal type. Each character sat on a rectangular body, and a kern was the part of the letterform that overhung that body so it could tuck against its neighbor — a delicate, breakable projection that foundries used sparingly. Compositors also inserted thin brass and copper spaces by hand to open up tight pairs. Letterspacing was so laborious that it was reserved for capitals and emphasis, which is where the old printers' rule against letterspacing lowercase originates. Phototypesetting in the mid-twentieth century removed the physical body entirely, letting characters overlap freely. That freedom produced the extremely tight, sometimes touching display typography of the 1960s and 1970s, seen in the work of Herb Lubalin among others.

Digital fonts carry kerning as data. OpenType kerning lives in the font's GPOS table, and browsers and design tools apply it automatically when it is enabled. In CSS, font-kerning controls it and letter-spacing applies tracking; a common production bug is kerning being silently disabled by other settings, which shows up as gappy capitals in headlines. Design systems typically encode tracking as part of the type scale, pairing negative tracking with large sizes and positive tracking with small sizes and uppercase, so the relationship is applied consistently rather than tuned per screen. Manual pair kerning survives mainly in logotypes and wordmarks, where a single fixed setting justifies the effort.

Look closely at the wordmark of almost any major brand and you will find spacing that no font would produce on its own. The pairs have been adjusted individually, often over many rounds, because the word will be reproduced at enormous sizes on buildings and at tiny sizes as an app icon, and both must look correct. The same care applied to body text would be wasted effort, since the font's kerning table already handles ordinary pairs and no reader is examining individual gaps in a paragraph. This is the practical rule the distinction produces: kern by hand where the setting is fixed and scrutinized, set tracking as a system everywhere else.

• →Kerning is pair-specific; tracking is uniform across a run.
• →Even typographic color, not equal distance, is the goal.
• →Large sizes generally need negative tracking; small sizes and uppercase need positive tracking.
• →Avoid letterspacing lowercase body text; it damages word shapes and slows reading.
• →Hand kerning is worth it for logotypes and short fixed settings, not for paragraphs.
• →Verify that kerning is actually enabled in production, not only in the design tool.