Sheepskin does not lend itself either to incising or to carving and is only useful for cheap work; it is very malleable and models easily, but for that reason lacks the firmness of calf when modelled. It is also not possible to get such good colour results with sheep-skin as with
calf, cow-hide, or ox-hide. It can be used for large work, such as wall-hangings, screens, etc., but is not recommended. Beginners, however, will find it useful on account of its low price.
Cow and calf are the most suitable leathers for really artistic work. Cow-hide may be obtained with either a glossy or a dull surface; the dull skins are sold specially prepared for decorating and give good results, the smoothness of their surface making them particularly suitable for modelling and pyrogravure.
Calf varies greatly in thickness and colour. It should be noted that in carved and modelled work the advantages of great malleability in the material are more than counterbalanced by the disadvantages; durable results cannot be obtained with very malleable leather which yields easily to the tool, and since high relief can be worked without difficulty in comparatively thick leather by damping it, its use is much to be preferred.
Ox-hide is frequently as thick as strong cardboard and is the ideal leather for carving, hammering and pyrogravure. In cut decoration a better effect can be obtained with this leather than with thinner skins, and being very firm, it is equally suitable for modelling.
Morocco leather, which is mostly of the kind called “Cape morocco,” is goat-skin with a grained surface produced by pressing hard seeds upon the skin while it is still damp from the tanning. For bookbinding and similar purposes this grain is crushed by pressing hot plates heavily on the surface. The only way of decorating leather so treated is by an inlay (or literally onlay) of skins of other colours, and is known as Leather Mosaic.[2]
[2] See the chapter on Leather Mosaic, p. [42].
The so-called Russia leather is generally very light and soft and well adapted to modelling on wax. It should not be cut.
Pig-skin is very firm and was formerly much used for
the fine stamped bindings of the fifteenth, sixteenth, and seventeenth centuries. It does not lend itself well to carving, but is very suitable for pyrogravure because of the contrast between its light tint and the dark brown mark produced by the hot tool.