Where would the book artist be without the bone folder? Used for folding, scoring, shaping, burnishing, pressing while gluing, and even cutting, the bone folder is an essential part of the hand book-making process. Classic bone folders, which are still used in book binding today, are made from real animal bones, often those of deer or elk. The smoothness and sturdiness of bone makes it ideal for making even folds and smoothing out surfaces, such as when gluing decorative papers or book cloth to binder’s board. Synthetic bone folders are also made. Ones of Teflon are particularly common in book making, as they will not leave a shiny mark when burnishing book cloth.
Most bone folders come in standard shapes: slim, straight pieces of varying lengths that can have either curved or pointed ends. The pointed ends can be used for scoring paper (as seen right) or working in corners. When making signatures from large sheets of paper, the pointed end of a bone folder can also be used to cut paper along creased folds to the desired size. The tapered sides of the bone folder allow for making tight creases while the rounded front and back of the folder can be used for burnishing decorative papers. The smooth finish of a natural bone folder, when rubbed across the paper, can smooth down the fibers.
While mass-produced books do not use bone folders (much larger machines are used to cut, fold, press covers, and polish paper), they are still a central tool in nearly every stage of hand bookbinding. If you stop by the Center for Book Arts, odds are you will not see anyone in the bindery without one!
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