exceptional volume
A term used by the Library Binding Institute to
indicate types of books—such as music
scores, certain art books, periodicals with narrow
binding margins or stiff paper— which
require good openability. The Institute specifies
that such volumes should be sewn through the
folds: when such sewing is used, any weak folds
are to be reinforced with bond paper (which is too
heavy for this type of guarding): loose leaves are
to be hinged, and the sewing done on tapes or
(sawn-in) cords. The term applies only to library
binding. (209 )