Glue is used for fixing on cloth corners, but strong paste is always used for leather. All edges and corners are well rubbed down with the folder and left smooth and sharp, but, on the other hand, the grain on the board side must be left uninjured. Insufficient paring of the corners or using only the fingers for turning-in causes very thick edges; such work is out of date and would not be done by any thoughtful workman.
Books bound in half-cloth or half-leather have the sides covered with paper; the latter often with cloth. When cloth sides are used, the material must always harmonize with the back both in regard to colour and texture. On each side to be turned in the paper is cut 1 to 1-1/2 cm. larger than the surface of the board to be covered. The paper is cut along the back with the knife and rule. The corners are turned down in half right-angles according to the size of the cloth or leather corners and somewhat smaller than these, and cut off with the shears as shown in the illustration, using the fold as a guide.
In ordinary work with very small corners, especially in large quantities, the corners may simply be cut off diagonally, and if there are many covers they are knocked up and the cutting is done with knife and rule or with the machine.
As a trade article for the publishers, the finished cover is lined with paper on the inside, both for the sake of improved appearance and to prevent the drawing outwards. For every board a sheet of paper is cut about 1/2 cm. smaller than the board and pasted on. The covers are placed between boards to dry.
Covers are generally decorated in some way; as a rule by means of the blocking press. Where they get any hand tooling, it is always done on the book when bound, for which no case is made in advance. Simple gold lines along the back and corners of the cover are excepted; such work is known as "filleting."