Equation 33-2 does not consider adverse conditions, importance of labels, or vision prob-
lems of readers. In some cases, it would be better to adjust sizes upward than to limit them
to the values from these empirical equations. This is especially true if one anticipates poor
lighting, information critical to safety, and the population of readers that may have vision
problems. If characters have long ascenders and descenders, the size of the main body of
the characters is the important dimension. Adjustments in overall height are needed to keep
readability high.