Characters have a specific space on both sides, which can be positive, negative, or zero. Setting these values for characters in a font globally is called setting its spacing. And in some cases, when specific pairs might result with a space that is too loose, too tight, or even with parts colliding, the designer needs to work on their kerning. Kerning is about adjusting the distance between such pairs whenever they are used next to one another and in that specific order, to give a smoother texture of the text.

Once a kerning value has been set for a pair of glyphs, those values can be repeated on every other pair with identical or similar shapes (e.g., V + A, W + A). Kerning can be set even with already published fonts in most applications (useful in justified texts), but great typefaces usually have these already fixed.