In this process, certain areas-of the design are brought into relief by lowering the background around them. The principle is the same as in transferring the pattern. The leather is dampened and those portions which are pushed down remain lower than the untooled parts.
Tooling should be done on a flat surface which will not absorb water from the leather. A slab of marble or a sheet of glass is excellent as it keeps the leather cool and provides a smooth surface. To lower the background evenly, use the broad end of the modeling tool illustrated. Dampen the leather until it is thoroughly moist, but not wet enough to give out water when pressed. Starting at the edge of the design, push the background down with short circular strokes of the modeling tool (fig. 20). Always work away from the edges of the design and be sure that the sharp edge of the tool does not come in contact with the leather. Even finger nail scratches will show and cannot be removed.
If you wish to increase the contrast between the raised design and the background, the latter can be lowered by stippling. In this process, the damp leather is tapped with point of the tracer, or small end of the modeling tool (fig. 21). The result is a pebbled surface which emphasizes the relief of the smooth areas.
One of the easiest ways of decorating an article is to run a single or double line around its edges. This is known as edge creasing and can be done on the damp leather with a rule and the pointed end of the modeler or with a special instrument known as an edge creaser (fig. 22). This is particularly useful in finishing belts. On thick leathers the edges are sometimes shaved with a beveler (fig. 23). This should be followed by the creaser to round the edges.
If you wish to raise your design in higher relief than the flat tooling provides, it may be pushed up from the back in the process known as embossing. In the case of small articles with fairly simple designs, this can be done by holding the dampened leather in the left hand and pressing up the part to be raised with the blunt end of the modeling tool (fig. 24). Keep glancing at the face of the article to make sure that the pattern is raised evenly. The leather stretches easily so pressure must be uniform.
If embossing is to be done on large articles which cannot easily be held in the hand, the leather may be placed face down on a pad of heavy felt or sponge rubber. The damp leather is then pressed down into the felt from the back as above. If this method is used, the pattern must be marked on the back of the leather as well as on the face to guide the modeling tool. To do this, cover a large piece of paper with chalk, shake off the surplus and lay the damp leather face up on the paper. Using the tracer, go over the lines which you have tooled on the surface with just enough pressure to make the chalk stick to the back of the leather in the same areas. When the leather is turned over and the excess chalk dusted off, the pattern will show clearly on the back.
When the embossing is finished by either of the above methods and the leather is thoroughly dry, it is generally advisable to stiffen or fill the raised areas so that they will not collapse as the article is used. One method is to coat the back of the embossed portion with a thin coat of fairly stiff flour paste. A second coat may be added after the first is thoroughly dry. A more widely used method is to fill the hollows caused by the embossing with strips of tissue paper coated with rubber cement. In this way layers of the filler are built up until they are level with the back of the leather. Lines can be filled with cotton cord or with small rolls of tissue paper.