In the days of hot metal we used to give a lot of thought to kerning, the adjustment the space between one character and its neighbor. The aim of good kerning is to give the impression that the space between all the characters in a word is exactly the same. This can only be achieved by making the space between characters different. The space between I and N will need to be more than the space between L and Y for example. Because of their similar shape, I and N will look closer together when they are exactly as far apart as L and Y. (This applies with lower case too — I used caps just to make the point more dramatically.)

Now kerning tables have been incorporated into typesetting software, and we have to think about it less and less. Of course some systems will do it better than others. Just about the only occasion now for active kerning is in a display line — especially if some quirky effect is being aimed at.

GalleyCat today brings to our attention KERNTYPE: a kerning game. Worth a look.