Mottled calf. A light brown calf bookbinding, made to look mottled by treatment with acid.
Niger goatskin. Brought from Africa by the Royal Niger Company. A native production. It has a very beautiful color and texture, with no grain. It has stood all the tests given it without serious deterioration. It does not keep clean under handling as well as a good coarse-grained morocco. Especially recommended by the committee appointed to investigate leather by the Society of Arts, of England.
Octavo. A sheet of paper folded into eight leaves, being, when folded, about 8½ × 5½ inches; usually written 8vo.
Off-set. The impression made by print against the opposite page, when a book has been rolled or beaten before the ink is dried; also called Set-off.
Opened edges. See Edges opened.
Out of boards. When a volume is cut before the boards are affixed it is done “out of boards.” Nearly all work is now done out of boards.
Overcasting. Sewing the leaves or signatures of a book together over and over. Usually done only when the book consists of single leaves or plates; but is quite commonly employed now in rebinding books, especially on the last two or three signatures front and back. Also called whip-stitching. Probably 90 per cent. of the books published today will stand wear better if they are properly overcast than if they are sewed in the ordinary way.
Pallet. Name given to the tool used in gilding upon the bands; sometimes applied to the steel box, with a handle, in which letters are fastened when they are pressed upon the back.
Panel. The space between bands; also applied to beveled and sunk sides.