Letterspacing (also known as character spacing or tracking) is the adjustment of the horizontal white space between the letters in a block of text. Unlike kerning, which affects only designated pairs of letters, letterspacing affects every pair.
Lowercase letters don’t ordinarily need letterspacing. Nor do capital letters when they appear at the beginning of a word or sentence, because they’re designed to fit correctly next to lowercase letters. But when you use capital letters together, that spacing looks too tight.
letter-spacing property in the range 0.05–0.12em (an em is 100% of the font size, so this is equivalent to 5–12%).
These are not absolute limits—use your judgment. But avoid the common error of spreading letters too far apart. If the spaces between letters are large enough to fit more letters, you’ve gone overboard.
Typographer Frederic Goudy is famously credited with opining that “Anyone who would letterspace lowercase would steal sheep.” But a few sources claim that his original comment concerned blackletter fonts, not lowercase, and that he used a more colorful verb than “steal.”
I accept the minority view on Goudy’s comment because, as Goudy was doubtless aware, sometimes lowercase should be letterspaced. Fonts intended for body text have spacing optimized for the 10–12 point range. But typographers will often add letterspacing to lowercase text smaller than 10 point to keep the spaces between letters distinct. Similarly, typographers will often remove letterspacing from lowercase text used at larger sizes (e.g., headlines).
If you use paragraph and character styles to make a style with all caps or small caps, include letterspacing as part of the style definition.