Kerning is the process of adjusting the space between two characters, or glyphs. This space is called a kerning pair. And the space between any two characters can be different than the space between any other two characters. There are many examples, in traditional typsetting, where known problems exist between letter pairs. For example, any time an oblique-sided upper-case letter is used with one of the four rounded lower-case vowels, the appearance of the type is greatly improved if the vowel is slightly tucked under the rising side of the upper case letter in such a way that the two letter spaces are actually overlapped. Because many of these problems are common to the majority of fonts, type designers — at least the good ones — have made it a point of honor to build into the font a table of kerning pairs.
In theory, a perfect font would have specific kerning information for each glyph in combination with every other glyph in both upper and lower cases. In fact the more kerning pairs that a font has is usually a good indication of how well crafted that font is. If the type designer has made every effort to insure that there are no unsightly spaces between letter pairs, then that designer has probably included many kerning pair instances. This is a process that takes time and a certain amount of experience.
TypeButter allows you to set optical kerning for any font on your website. If you’re longing for beautifully laid out text that today’s browsers just don’t provide, this is the plugin for you!