The Decoration of Leather Part 3

STAMPED LEATHER

It is beyond the scope of this work to describe the process of stamping leather with a steel die and a balance-press;[7] we will therefore explain a method in which the steel die is replaced by thick cardboard or leather cut out in open-work, and the balance-press by a small one worked by hand.

The cardboard or leather stencil, laid on damp leather and placed in the press, will sink in, causing those parts of the leather which are against the open parts of the stencil to stand out in relief.

[7] _Balancier._

There is another method which has been found particularly satisfactory in working a deep design on the board of a book-binding. The design is drawn sharply in outline with a pen upon very white paper. By a photographic process a metal block is produced from the drawing, on which the outline appears in relief. This block, mounted on pasteboard or wood, will form a die with which the design can be hollowed out of the leather by pressure in a copying-press, and the result subsequently perfected by cutting or modelling.

Another interesting process consists in etching a design deeply upon a copper-plate; the lines are then filled in with printing ink, the surplus removed with the palm of the hand, and the plate wiped over with a soft rag, preferably of flannel. A piece of leather is then wetted and placed under the plate and the whole heavily pressed. Since a copying-press is not sufficiently heavy to produce the relief, a bookbinder's press should be used and tightly screwed up. When the leather has taken the impression sufficiently, the whole is removed from the press, and the copper-plate carefully raised, avoiding tearing the leather if it should have stuck to the plate. The design will then stand out in relief, coloured black or red according to the ink used. The ink must be thick enough not to spread over the leather under pressure.

There is also a method of stamping leather by means of two plaster casts prepared with stearine, both bearing the same design, one in relief and the other hollowed. A thoroughly wetted piece of thin leather is placed between these two casts and well pressed, the amalgam enabling the plaster to bear the pressure. The leather should be allowed to dry between the casts, or, if preferred, the hollow one may be removed.

The same principle can be applied without the hollow cast, by modelling the leather with the modelling tool, so that it takes the form of the cast in relief beneath it. In some cases the plaster is left permanently under the leather to form the padding.

[Ill.u.s.tration: FIG. 17.--CUTTING-OUT KNIFE]

OPEN-WORK LEATHER

The leather should be neatly and sharply cut out for open-work decoration, and placed over a groundwork of leather, stuff or metal: the last material is well adapted by its contrast of colour to show up the ornament laid over it. Open-work leather is a good material for hangings, and when destined for this purpose the design is sewn on the groundwork of leather or stuff with a sewing-machine, or stuck with gutta-percha. In the latter case the back of the leather is made quite smooth, and a layer of gutta-percha is placed on it and made to stick by means of steam produced by heating a wet pad. Well pressed down with this pad the gutta-percha will stick to the leather, and also cause it to keep in place on the groundwork, to which it is made to adhere permanently by pa.s.sing a hot iron over the surface. A sheet of white blotting-paper is laid over the leather to protect it. When the leather is worked in relief, this proceeding must be reversed, that is to say, the leather is placed face downwards on a sheet of wadding with the material forming the groundwork uppermost, and the hot iron is pa.s.sed over the back of the material. The relief can easily be worked on the leather before it is cut out.

The cutting out is done on a piece of strong cardboard with the knife ill.u.s.trated in Fig. 17.

[Ill.u.s.tration: 7. CASE OF CUT AND PUNCHED LEATHER. GERMAN, 15TH CENTURY.]

The borders of open-work leather can be ornamented by a sort of plaiting formed by lacing thin strips of soft leather through holes made with a punch.

A very effective decoration for furniture can be made with open-work leather over a panel of wood, or a metal background.

CHAPTER III

LEATHER MOSAIC

Until recently it seemed as if this pleasing art would have to remain the monopoly of a limited number of professional craftsmen working with numerous tools, and reckoning a ten years' apprentices.h.i.+p necessary to the attainment of proficiency in their craft. But although there is small likelihood of amateurs entering the domain of the followers and emulators of artists such as John Reynes, Florimond Badier, Monnier, Padeloup and Jubert, Mons. Eugene Aumaitre has invented a simpler process of leather mosaic, for which fewer tools are required and which is within the reach of artist and amateur alike. The following pages contain the result of the study of his method, with the addition of some observations based on the practical experience of the author.

LEATHER FOR GROUNDWORK

Any skin may be used for the groundwork of leather mosaic, but morocco, and especially the kind called Cape morocco, is generally preferred, because of the grained surface which shows up the inlaid decoration to the best advantage.

Other skins, however, with either dull or glossy surfaces make good backgrounds for mosaic decoration, and as they are generally fawn coloured, they may first be stained to produce shaded groundwork very attractive in effect.

The old masters of leather mosaic made great use of fawn-coloured calf, occasionally adding a touch of coloured lacquer to bring out the light parts of the design.

PREPARATION OF THE LEATHER FOR THE GROUNDWORK

The first necessity in working leather mosaic is to have a flat and rigid surface to work upon; it is indispensable therefore, when the leather is not in itself sufficiently thick and firm, to stretch it on cardboard.

This rather troublesome preparatory process is best confided to an expert; we will, however, describe it for the benefit of those preferring to execute it themselves. A strong, smooth piece of cardboard called millboard is taken, and the edges rubbed down with gla.s.s paper. A thin coat of paste is applied on one side of the board and allowed to dry.

[Ill.u.s.tration: FIG. 18.--PARING KNIFE]

[Ill.u.s.tration: FIG. 19.--PARING KNIFE]

The edges of the leather must now be thinned so that they will more readily stick when turned over and pasted under the board, and also to avoid the unevenness which the normal thickness of the leather would produce underneath. A paring-knife with a broad, flat, very sharp blade (Figs. 18 and 19) is used for this purpose; its manipulation is difficult and requires long practice. The handle is held against the palm of the hand, and the fingers extending over the blade cause it to penetrate the leather superficially by a more or less strong pressure, the object being to take off shavings from the back of the skin, increasing towards the edge until the edge itself is reduced to the thickness of a cigarette paper.

[Ill.u.s.tration: FIG. 20.--PARING LEATHER]

The leather is placed surface downwards on a lithographic stone or a slab of marble. It is held stretched with the left hand, the fingers being extended over it on the face of the stone, and the thumb pressed against the side leaving the part just in front of the fingers free to be pared (Fig. 20). It is of the first importance for the success of this operation that the leather should be kept well stretched. The knife is held almost horizontally to avoid cutting into the leather at too sharp an angle, and is worked from left to right towards the edge.

The leather is then fastened to the cardboard by pasting either the whole of it or only the edges, which are turned underneath. In any case ordinary paste should be used; seccotine or glue would sink into and harden the leather, making the subsequent outlining process difficult.

When the piece of leather is so large that it would cause the board to warp when it dries, some paper should be pasted on the other side of the board, which will keep it flat by drawing it in the opposite direction.

[Ill.u.s.tration: 8. BROWN LEATHER BINDING, CUT AND ENGRAVED, WITH PUNCHED BACKGROUND. _GERMAN MS. CHRONICLE OF EVENTS._ GERMAN, 15TH CENTURY.]

The work is then put into the press or under heavy boards. It is important that this should always be done after paste has been used. When it is too large to put into a copying-press, it should be laid upon a flat table and a sheet of nickelled or very smooth zinc placed against the part to be decorated. The cardboard known as _Carton Jacquart_ may be subst.i.tuted for the zinc, but there is a risk that the moisture of the paste penetrating the leather may cause it to swell, notwithstanding its glaze. The zinc plate or the board should not be smaller than the leather, for in that case the pressure would produce a ridge round its edge.

The groundwork is ready to receive the ornament as soon as it is dry. The different methods of working mosaic will now be explained in turn.

MONOCHROME MOSAIC ON CALF

In this style of decoration the leather used for the inlaid design is white or very light in tone, and may be dyed subsequently to present the appearance of a mosaic made of variously coloured leathers.

LEATHER FOR INLAYING

The skins sold for this purpose are split sheepskins. Their extreme thinness renders them liable to stretch a great deal, and therefore they are most difficult to cut out in any desired shape. To obviate this difficulty, the back of the leather is pasted over, and it is then stretched on a board and fastened with drawing-pins to prevent it from shrinking as it dries. But there is another and a better method--that of mounting the leather on paper.

MOUNTING THE LEATHER ON PAPER

Some paste is made of very light and smooth flour, diluted with half the quant.i.ty of water and beaten to a cream. The water is added in small quant.i.ties while the mixture is being stirred. Canson paper, or some other strong drawing paper, is pasted over the whole surface of the leather, so that it adheres lightly, and can be removed afterwards without difficulty; it is then placed under boards and allowed to dry thoroughly.

TRACING THE DESIGN ON THE PAPER

The design is traced by means of carbon paper on the paper lining of the inlay leather. A hard pencil should be used in order to produce very sharp lines.

CUTTING OUT THE DESIGN