The leather must be wet in order to take the impression of the tracing. A soft, slightly damp sponge is passed several times evenly over the whole surface; if only a part of the leather were wetted an aureole would form round that part and would leave a permanent mark. When the leather has once been wetted all over there is no further fear of this, and it may then be damped again in parts when necessary. Practice alone will make it possible to judge accurately the degree of saturation that each skin requires to bring it into a fit condition for working on; speaking generally, the water should have penetrated the leather so that the pressure of the tool will not bring it back to the
surface. Neglect of this rule might result in staining the leather.
FIG. 1.—TRACING-POINT
The design is transferred to the leather by means of a metal tracing-point (Fig. 1). An agate or ebony point, or an exceedingly hard 6H graphite pencil, may also be used for the purpose. The pencil possesses the additional advantage that it can be given a very fine point where an extra thin and sharp outline is required. Doubling the outline by going over it twice should be avoided. From time to time the tracing-paper or linen should be raised to see that the design is being well marked on the leather. The outline should be dark; when it comes light it is a proof that the leather is too dry and requires damping again.
INCISING THE LEATHER
This being the first operation in working thick leather by carving, engraving and modelling, it will be dealt with before passing to the different processes peculiar to these methods of decoration. The incising is done after the design has been traced. There are numerous incising knives for the purpose which vary in shape and are manipulated in different ways; no one of them can be specially recommended as notably superior to the rest, and the artist should choose the one with which he feels most likely to succeed. The knife illustrated in Fig. 2 is used with a downward movement and is held—as shown in Fig. 3—very short, so as to obtain a sufficient purchase over the blade which is guided by the middle finger. The knife illustrated in Fig. 4 is used upwards. Fig. 5 shows the manner in which it should be held to produce a vertical cut. It will be found of great assistance in making a good firm cut to guide the right hand
with the left hand as in Fig. 5. When curved lines are to be cut, the left hand must be used to turn the leather so as to present it in the most favourable position for the operation of the blade. The third knife (Fig. 6) is held like a graver with the handle supported against the palm of the hand and is pushed forward (Fig. 7). It is useful in cutting curved lines over a large surface. The depth of the incision should vary according to the effect
to be produced by the subsequent operation, but it should never exceed a third of the thickness of the skin.