When employed by a skilled person, manual kerning will usually give better results than optical kerning; for example, some characters that may appear to an algorithmic comparison to be spaced very closely together may appear to a human reader too far apart, especially when the only element of a glyph that is “too close” is a diacritic mark. Manual kerning may even be better than the metric kerning built into the kerning table by the font's designer, since these tables often have errors or omissions, or the difference may simply be a matter of personal preference.