Each type face may offer a wide choice of alphabets, e.g. capitals and lower case. The use of different alphabets can help to provide the contrast necessary to avoid making the form look dull in appearance. A reasonable way of using the type available is to employ Roman for the bulk of the work, Italic for instructions, and Bold Face for emphasis—a better expedient than underlining.
Capitals should never appear in the middle of a line of lower case, nor should they be used for continuous text, though EVEN SMALL CAPITALS may be used judiciously for emphasis (letterspaced examples: SMALL CAPITALS SPACED THUS). Capitals and lower case are better for long captions and matter in text because they are easier to read than capitals in long lines. For two or more lines to be read together lower case is always better than capitals: compare pages 126 and 127.
Small capitals may be used for occasional emphasis or minor headings, and capitals reserved for the more important headings. However, capitals do not invariably dominate lower case. Typographers frequently reverse the traditional order by having a main heading in large capitals and lower case, and the small heading in capitals as on page 112. Much depends on the length of wording in the respective lines.