Font spacing characteristics

Fonts can be classified according to their spacing characteristics and by their format.

Uniformly spaced fonts
Uniformly spaced fonts, or monospaced fonts, are similar to typewriter fonts, for which each character increment is the same width. Thus, the lowercase i and the . (period) each occupy as much space as the uppercase M. Examples of uniformly spaced fonts include Courier and Letter Gothic.
Note: A character increment is the distance that the current print position is increased for the particular character printed.
Duospace fonts
Duospace fonts are similar to uniformly spaced fonts or monospaced fonts. Duospace fonts can be two character widths instead of a single character width. Ideographic characters are designed on full-width increments while other characters can be designed for half-width increments. This concept allows the half-width and full-width characters in the box size examples in Box size examples to be implemented in a single font.
Note: As more language support is implemented in duospace fonts, more character widths can be used. However, the characters widths are always a multiple of the half-width character increment. This function allows a monospaced appearance of the data using this font spacing.
Typographic fonts
Typographic fonts are proportionally spaced fonts. The character increment is part of the design and varies on a character-by-character basis. Thus, the lowercase i and the . occupy narrow spaces. The uppercase M occupies a wide space. Examples of typographic fonts include Helvetica and Times New Roman.
Uniformly spaced fonts are often described or referred to in pitch, or the number of characters printed in one horizontal inch (Figure 4.). Pitch is also referred to as characters per inch (CPI).

Type size in pitch

This picture shows type size in pitch. In the example, 10-pitch is equal to one inch.
All fonts are measured in points, the vertical size of the font. One inch is equal to approximately 72 points. Point size is a baseline-to-baseline measurement, which includes minimal white space. The baseline is the line upon which the characters rest. Thus, the actual height of the characters in an 18-point font is fewer than 18 points (Figure 5). The line spacing usually includes one or more extra points of white space between lines of type.

Type size in points

This picture shows type size in points. In the example, 18-point type is equal to 1/4 inch.
Box size
Double byte character set (DBCS) raster fonts were formerly measured in box size, the number of pels in the character box. Box size can be either a horizontal or a vertical measurement. Usually both dimensions are given, with the box width first. If only one dimension is given, it is the box height. In full-width fonts, the box width is usually equal to the box height. In half-width fonts, the box width is one-half the box height.