User Guide

Determining proper widths for each character in a font is a
difficult task, because each letter can appear alongside any
other letter. You can imagine that a spacing value for “W”
which looks good for “Wo” may not look as good for “Wh”
so finding the “right” values to use is a matter of looking at
lots of examples, and making some trade-offs. This is
sometimes easier said than done: If your font has 200
characters in it, for instance, there are 200 x 200 = 40,000
different character combinations to consider!
Some letters can never really be spaced correctly for all
possible combinations. For example, the “T” usually
presents some problems.
Now, of course, you have a new problem.
Clearly, you can fix some of the spacing problems some of
the time, but never all of the spacing problems all of the
time. Which brings us to kerning, and what it is.
Pair kerning
Pair kerning lets you get around those sorts of difficulties.
With a properly kerned font, you can actually get perfectly
wonderful character spacing all of the time, with a bit of
Fontographer User's Manual
5: Metrics: Spacing and Kerning Page #5