A Quick Guide to Arcane "Desbib" Vocabulary and Format Detection
"Edition": All books printed from a single setting of type.
|"Impression": all copies of an edition printed at any one time||"Issue": all copies of an edition packaged for sale by a book seller|
"State": Differences in individual copies of the same edition/issue caused by deliberate corrective changes in the way any page's type was set during printing, or by wear and tear on individual pieces of type or engravings or ornaments (e.g., printers' colophons).
Format Detection for the Four Most Common Formats in Early Books
Chain line orientation? Watermark location?
Vertical (folio or octavo) center & whole = folio (Fo)
divided upper gutter corner = octavo (8o)
Horizontal (quarto or duodecimo) in middle of gutter & half = quarto (4o)
1/3 from top/bottom outer edge = duodecimo (12mo)
When in doubt, print a copy of the Goucher watermark paper and do the folding exercise, always remembering to rotate the sheet after each fold and before the next in a clockwise direction so that the folds remain on the top.
(Exceptions? Any format can be printed by "half-sheet imposition," so that two identical sets of pages are set up on each half of the sheet, which is then cut in half before binding to make leaves for two different books. See Williams and Abbott, and Philip Gaskell for examples.)