The collector will also find it convenient to catalogue the books in his cases, preferably by means of a card-index system. Cards three by five inches usually will be found large enough to hold a fair description. Each card should be headed with the author’s name, for convenience in indexing, followed by the book title, an exact transcript of the title-page or colophon, a description of the illustrations, if any, the size and the binding, and any bibliographical notes of interest. The price paid for the book, written in cipher, and the date purchased, should also be added.
The matter of correctly noting the size of books for such a catalogue or index is one to which the amateur will be obliged to give a certain amount of study, and he will find, among bookmen, wide differences of opinion as to the proper methods to follow. For all ordinary purposes, the descriptions of folio, where the sheets are folded into two; quarto (4to), where the sheets are folded into four; eight sizes of octavo (8vo), from fcap. to imperial, where the sheets are folded into eight; duodecimo (12mo); and sextodecimo (16mo) will be found sufficient. Speaking generally, a 4to will have a page signature at the foot of every fourth page, an 8vo at the foot of every eighth page, a 12mo at the foot of every fourth or twelfth page, etc. The old standard for octave sizes (measured on the edge of the pages, not the boards), which may safely be followed, is given in the table below. The sizes will be found to vary somewhat, where the book has been trimmed or where the paper used has been of an odd size.
Table of Octavo sheets, folded:
| 4¼″ | × | 7″ | fcap 8vo |
| 5″ | × | 7½″ | crown 8vo |
| 5½″ | × | 7½″ | post 8vo |
| 5½″ | × | 8″ | demy 8vo |
| 6″ | × | 9½″ | 8vo |
| 6½″ | × | 10″ | roy 8vo |
| 8¼″ | × | 11½″ | imp 8vo |