Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

concertina guard

A type of GUARD (1) used in conservation binding. It is made of good quality paper (generally Japanese copying paper) and is used so that the adhesive applied to the spine does not come into direct contact with the sections. The depth of each fold does not normally exceed 1/8 to 3/16 inch. The use of the concertina guard makes pulling of the book easier in the event that rebinding is necessary, and also reduces the possibility of damage to the folds of the sections. A forerunner of this technique consisted of loose individual guards around each section of vellum books. This type of guard is used only in the best conservation binding because it is difficult and time consuming (therefore expensive) to sew a book when using the concertina guard.