You have two books. They appeared in the same year, or at least they have the same year on the title page. The title and the imprint are identical; the number of pages and the collation are exactly the same; word-by-word and line-by-line, the texts are identical. Yet at once you notice the difference between the two: the words are spaced differently; different ornaments and capitals have been used; there are small differences in spelling and punctuation; in other words, the books were printed from different type-matter, and therefore there are two different editions which merit two separate descriptions.
Two other books are on the table. Their titles are more or less the same, but one is published by book seller A, the other by B. Close examination of the books, however, shows that apart from the title pages, the books are identical. They are title editions.
Third case. You are looking at a first impression of a book and a 'Second, revised and much improved impression'. However, this appears to be a title edition as well; only the title page is new, the rest is the apparently unmarketable first edition (a forgery, but that is the only connection between the STCN-fingerprint and crime).
As said before, these differences are easy to establish when you have the books at hand. But what to do if one of them is in Amsterdam and the other in The Hague? The STCN-fingerprint makes it possible to identify the edition of any given book. Title editions are unmasked and apparent doubles can be distinguished from one another. With the fingerprint it is even possible to identify books which lack a title page.
How does the fingerprint work? Books were made by printing sheets of paper on both sides, folding them into gatherings and binding them. For the convenience of the binder, on the first leaves of each gathering letters and numbers were printed. These signatures were indifferently put underneath the bottom text line. It is this indifference that makes them useful for the fingerprint. Even though the text of a book is accurately set to the example of an earlier edition, and even if the original lay-out is followed meticulously, in different impressions the signatures are never in the same position, simply because there was no reason for the type-setter to pay attention to it. A different fingerprint means a different impression.
The fingerprint is made by entering the signature of certain pages, followed by the piece of text in the bottom line that is directly above the signature. The chosen pages are the first and last of the preliminaries, main text and appendices. The fingerprint always begins with the combination of the year of publication and bibliographical format.
An example. Here are photographs of the title page and the first and last signed pages of the first edition of Vondel's Gysbreght van Aemstel. It is an edition in 4° from the year 1637, so the first element of the fingerprint is
The first signed page is A2. Directly above the signature A2 are a comma, a space, and the word 'en'. The fingerprint of this page, in STCN--notation, is
b1 A2 ,$en
where b1 indicates the first signature of the main text. The space is indicated by an $. The letter r before the comma and the space after 'en' are not entirely above A2, and are therefore left out.
The last signed page is I2. Above the signature are the letter a, a comma and a space. This fingerprint is quoted as
b2 I2 a,$
The complete bibliographical description of this edition is as follows:
Vondel , Joost van den
Gysbreght van Aemstel, d'ondergang van zijn stad en zijn ballingschap. Trevrspel. / By I.V. Vondel. Amsterdam, W. Blaev, 1637. 4°: A-I4.
163704 - b1 A2 ,$en : b2 I2 a,$