Kerning allows you to alter the space between two characters in a line of text. Kerning is useful when two characters look unbalanced or too far apart. Small kerning changes between the two characters can improve their appearance. This is often necessary in very large headline or banner text where the "balance" of the characters is highly visible. Kerning is measured in em's (the width of an "M" in the current font and font size). For more details, see Kerning text.