Fig. 1.
Fig. 2.
In correct usage the upper parts of the figures 8 and 3, also of the letters Z, X, B, H, and S, are made smaller than the lower parts. The reason for this is demonstrated in figures 1 and 2.
In figure 1 the upper and lower parts are made mechanically equal. In figure 2 the upper parts are smaller. We accept the characters of figure 2 as the correct forms because in figure 1 they appear "top heavy." We must adapt the proportions to a pleasing appearance and not to mechanical exactness.
An important factor which must be dealt with in lettering is that the human eye is not always a true discerner. A few simple well-known diagrams in addition to those of figures 1 and 2 will illustrate this point. See fig. 3.
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