Line and character spacing

The vertical space between lines of type is called leading (rhymes with sledding). Leading is measured from the baseline of one line of text to the baseline of the line above it. Baseline is the invisible line on which most letters sit.

The default auto-leading option sets the leading at 120% of the typeface size (for example, 12‑point leading for 10‑point type). When auto-leading is in use, the leading value appears in parentheses in the Leading menu of the Character panel. You can change this default auto-leading by choosing Justification from the Paragraph panel menu and specifying a percentage from 0 to 500.

By default, leading is a character attribute, which means that you can apply more than one leading value within the same paragraph. The largest leading value in a line of type determines the leading for that line.

Shift the baseline

Use Baseline Shift to move selected characters up or down relative to the baseline of the surrounding text. Shifting the baseline is especially useful when you’re hand-setting fractions or adjusting the position of a picture font.

Adjust kerning and tracking

Kerning is the process of adding or subtracting space between specific pairs of characters. Tracking is the process of loosening or tightening the spacing between the characters in selected text or an entire block of text.

You can automatically kern type using metrics kerning or optical kerning. Metrics kerning (also called Auto kerning) uses kern pairs, which are included with most fonts. Kern pairs contain information about the spacing of specific pairs of letters. Some of these are: LA, P., To, Try, Ta, Tu, Te, Ty, Wa, WA, We, Wo, Ya, and Yo. Metrics kerning is set as the default so that specific pairs are automatically kerned when you import or type text.

Some fonts include robust kern-pair specifications. However, when a font includes only minimal built‑in kerning or none at all, or if you use two different typefaces or sizes in one or more words on a line, you may want to use the optical kerning option. Optical kerning adjusts the spacing between adjacent characters based on their shapes.

You can also use manual kerning, which is ideal for adjusting the space between two letters. Tracking and manual kerning are cumulative, so you can first adjust individual pairs of letters, and then tighten or loosen a block of text without affecting the relative kerning of the letter pairs.

When you click to place the insertion point between two letters, kerning values appear in the Character panel. Metrics and optical kerning values (or defined kern pairs) appear in parentheses. Similarly, if you select a word or a range of text, the tracking values appear in the Character panel.

Tracking and kerning are both measured in 1/1000 em, a unit of measure that is relative to the current typeface size. In a 6‑point font, 1 em equals 6 points; in a 10‑point font, 1 em equals 10 points. Kerning and tracking are strictly proportional to the current typeface size.

Adjust kerning

Adjust tracking

Turn fractional character widths off or on

By default, the software uses fractional character widths between characters. This means that the spacing between characters varies, and will sometimes use only fractions of whole pixels.

In most situations, fractional character widths provide the best spacing for type appearance and readability. However, for type in small sizes (less than 20 points) displayed online, fractional character widths could cause type to run together or have too much extra space, making it difficult to read.

Turn off fractional widths when you want to fix type spacing in whole-pixel increments and prevent small type from running together. The fractional character width setting applies to all characters on a type layer—you cannot set the option for selected characters.