Another obvious difference is _bulk_, calculated in accordance with the publisher's notion, first, of the general sense of trade expectation and, secondly, of the purchasing psychology of a public habituated to certain selling prices vaguely related to number of pages and thickness of volume (inconsistently enough, weight does not enter into these expectations). These habits of mind have consequences in the typography; they affect the choice of fount and size of type, and may necessitate the adoption of devices for "driving out," i.e., making the setting take up as much room as possible. By putting the running headline between rules or rows of ornaments; introducing unnecessary blanks between chapters; contracting the measure; exaggerating the spaces between the words and the lines; excessively indenting paragraphs; isolating quoted matter with areas of white space: inserting wholly unnecessary sectional titles in the text and surrounding them with space; contriving to drive a chapter ending to the top of a recto page so that the rest of it and its verso may be blank; using thick paper; increasing the depth of chapter beginnings and inserting very large versals thereto; and so on, the volume can be inflated to an extra sixteen pages and sometimes more--which is a feat the able typographer is expected to accomplish without showing his hand.
Limited editions of standard authors, or of authors whose publishers desire them to rank as such, are commonly given a rubricated title or some other feature not strictly necessary. A dreadful example of overdone rubrication is to be found in an edition of Thomas Hardy's verse, in which the running heads throughout the book are in red--the production of a firm which desired to make an impression on the purchaser in view of the price asked for the edition. This could have been better done by reserving colour for the initial letters. Handmade paper is generally used for _éditions de luxe_, and none but the brave among publishers will disregard the superstitious love of the book-buying classes for its untrimmed, ugly and dirt-gathering edges. That most of the public prefer to have it so is because a trimmed book looks "ordinary" to them. Any book which is "different" from the "ordinary" in one superficial way or another is apt to impress those lacking trade experience. And there has been a notable increase during recent years in the category of books, generally illustrated, known to the trade as _fine printing_, _éditions de luxe_, _press-books_, _limited editions_, _collectors' books_, etc. Hence, it is hoped that the above setting out of the first principles of typography may give the discriminating reader some sort of yardstick which he can apply not only to the entries catalogued by the book-sellers as limited editions, but to the output of publishers responsible for printing the literary and scientific books which are more necessary to society, and are often designed with greater intelligence.