User Guide

is 50% wider than the right stem, the serifs are chunky and
irregular, the cross bar is too heavy, and most importantly, it
doesn’t match the outline.
What we would like is something like this:
That’s where hinting comes in. As we’ve shown, you can’t
simply turn on pixels just by looking at the outline if you
expect to wind up with a decent character. More
intelligence has to be added in.
Hinting works by feature recognition. Hints basically define
interesting features such as vertical stems, horizontal stems,
serifs, cap heights, x-heights, etc. For example, in the case
of the H, there is information in the font which says things
like “I don’t care where on the pixel grid the outlines fall; the
left stem and the right stem must be the same width!” Hints
can also control global font-wide attributes such as x-
heights, so the tops of characters like x, n, c, m, etc., are all
aligned properly at all sizes.
Hinting is most important at low resolutions, because there
are fewer pixels to define the character image. At high
resolutions, it’s easy to get a good image; there are so many
pixels to deal with, the differences hinting makes are not
normally noticeable or important. The figure on the right is
how our “H” example might look on a Linotronic at very
high resolutions.
Since hinting can control at most one pixel’s difference
either way, the human eye can’t usually perceive the
difference hinting makes at high resolutions.
To sum up: A hint is special information placed into a
character’s outline definition that causes the character’s
outline to be adjusted in a way that improves the
character’s perceived shape when printed.
Fontographer User's Manual
10: Expert Advice Page #16