Fig. 63—Paring with French knife.
In an ordinary bindery thin or split leathers are mostly used; these do not require very much paring, which is only necessary for pig-skin and the finest moroccos. The latter leather is narrowly pared about 2 to 3 mm. wide along the edge for half as well as for whole bindings. Only the back is pared the whole width, therefore 1 to 1-1/2 cm. has to be nicely gradated. Broken places, inequalities of the edge, or even holes to be filled in, greatly add to the difficulty of the work.
In the thicker skins also—thick places often occur in the otherwise thin skins—the joint must be thinned down. The packing is laid upon the wrong side of the leather and its position marked out with the folder. The leather is pared about 1 cm. in width along this line, that is to say, it is pared so that 1/2 cm. right and left along the mark the thickness of the leather is reduced.
As a rule, first-class books are not provided with a cover made in advance, and even those described by publishers as "super extra" do not rise above morocco goat.
We have to do with the following leathers which are mostly used for the publishers' bindings: Goat-skin (of oriental hybrid sheep), morocco goat, sheep-skin (unsplit sheep-skin), and split sheep-skin [or so-called skivers]. There is another goat-skin, not Levanted, sold and used under the name "bastard" leather. "Levanting" means to imitate by pressing the grain natural to the skins from the Levant. Most kinds of our leather receive their grain by such process.
For whole-leather bindings a narrow margin is pared down all round the edges, the turn-in at the back is pared just as much as is necessary, and also at the corners. The leather corners are cut slant-wise at the outset, and the paring is done so that the thinning begins exactly at the edge of the board.
In leather bindings the board, as well as the back packing, is glued on, rubbed down, and the edges then pasted and turned in, the leather is rubbed down sharply in the joint, the back, and on the edges; but a folder must never be used on the leather covering the board itself.
It frequently happens that the board is finished off with round corners; in this case, the method of turning in cloth as well as leather is slightly different. The two neighbouring edges are turned in. The leather or other material is cut off not quite so close as for square corners, and the material is drawn very smoothly and neatly over the edges in little folds, using a pointed folder for the work.
Books not wholly covered with cloth or leather get corners of the same material as is used for the back. Cloth corners are not cut singly, but a strip of material long enough for the required number of corners is glued and then cut with the shears into pieces of this shape(a) or, better(b), placing them on the boards in such a way that the material projects a little over the corner of the board. First of all, the lappets of the top and bottom edges are turned in, the corners nipped in the manner shown, and then the lappets of the fore-edge are also turned in. Leather corners are treated in the same way, but these are cut from waste pieces according to the zinc stencil plate kept for the purpose, and then pared down.