Pottery, for Artists Craftsmen & Teachers Part 8

Only where the gold was fired on a white clay is there any iridescence, and then hardly so p.r.o.nounced as to deserve the name of l.u.s.tre. The bis.m.u.th and other l.u.s.tres made by the modern potter are combinations of metallic oxides and resinates dissolved in ethereal oils. These are painted on the glaze, transparent or opaque, but having almost invariably a lead base, and then fired at a dull-red heat. The medium disappears, and the metal in a finely divided state is deposited on the surface of the glaze. This, however, gives a painted look very different from the lovely irradiance of the Persian Hispano-Mooresque or Italian work.

With these the l.u.s.tres were fired in a reducing atmosphere, one supercharged with combustible gases, the metals decomposed and fixed to the semifluxed glaze. The manipulation was not infallible and was attended with much risk; but the successful pieces are unrivalled, and according to Piccolpa.s.so "paid in gold." De Morgan, who more nearly approached the works of the Italian masters than any other modern potter, used a very similar medium and method with his fine l.u.s.tres. In the last few years l.u.s.tres have been brought to such perfection, in preparation, application, and firing, that accident is practically eliminated. Glorious colours and gorgeous effects are obtained. Yet it may be said without senseless adulation of the merely mediaeval that nothing has been produced superior, or even akin in spirit, to the work sent out from Persia, Spain, or the botega of the inimitable Maestro Georgio of Gubbio.

l.u.s.tres may be bought ready to apply. They are then painted on the glazed pot, which is re-fired at a dull-red heat in the ordinary oxidizing atmosphere. Once the painted look has been contrasted with the l.u.s.trous appearance of the _reduced_ effects there is only one kind of l.u.s.tre for the artist. Fortunately, perhaps, their preparation is not easy, and the correct method of reducing is a difficulty to be overcome by practical experiment alone. Hainbach gives many practical receipts for l.u.s.tres that are not beyond the scope of a craftsman. The reducing atmosphere can be obtained in an open kiln by the introduction at the right moment of any combustible giving smoke free from all traces of sulphur.

In firing with a m.u.f.fle kiln the introduction of coal-gas free from sulphur is a matter attended with some risk at the necessarily low temperatures required by the l.u.s.tres. It should be approached with caution, and each mixture will have a varied firing point, the correctness of which is established only by trials.

l.u.s.tres applied with skill and restraint enhance the most beautiful glaze, but in unskilled hands they inevitably vulgarize and cheapen. The fresh, unsophisticated renderings of the Persians or the Moors and the virility of the Italians should be studied, but not merely imitated before working in this medium.

[Ill.u.s.tration: FIG. 55--PAINTING OUTFIT.]

CHAPTER XIII

DECORATION

"The world is still deceiv'd with ornament."

--_Merchant of Venice._

Decoration has been touched upon briefly in one or two of the preceding chapters. To attempt a description of the various kinds of decoration which it is possible to place on a pot, another book would be needed.

Their name is legion. They range from the simple and entirely satisfactory work of primitive and peasant peoples to the wonderful enamel decorations of the Chinese. With such an enormous field and varied choice it is difficult to particularize and foolish to dogmatize. The hints below are intended but to stimulate interest in the at present unexplored fields that lie beyond the beaten track.

Any representative collection of ceramics will prove a veritable treasure house of suggestion to the student. All will be there. The difficulty is to choose, and choose aright. The bold brushwork of Cyprus foils the marvellous _familles_ vert and rose of the Chinese, the faultless Wedgwood sets off the virile Toft. One sees how the Italians, with almost crude colours,--blue, green, red, yellow,--developed their wonderfully robust school of figure painters; then their fanciful _arabesques_ are prolific of ideas. The Greek style--red and black and white--is a rich field waiting for the reaper. The peerless Persian pots, the plaques from Spain, the steins and stoves from Germany, the fresh Delft wares; these and many others crowd round for recognition and disconcert the choice.

But having come so far, let us not choose the horrific style that models most faithfully a cabbage, tops it with a lifelike snail as handle, and cunningly converts the whole into a vegetable dis.h.!.+... (in S. K. M.).

Nothing should be more distressing to the artist than to see great skill and craft thus misapplied. Yet how often does the search after false originality lead only to meretricious cleverness or vulgarity, which creeps in unseen during the too close struggle with the craft.

But our muttons need tending. Broadly speaking, all decoration falls under three heads: Glaze; Relief; Painting;--subdivided into many combinations of these three cla.s.ses.

The application of glaze has already been described. A pot possessing a n.o.ble form and glaze is obviously in no need of _decoration_; no artist would attempt it. The Chinese and j.a.panese are safe guides here. Their rich glazes and fine forms are set off in the simplest and most effective manner. This is potting, pure and simple.

Under relief, we group all modelling,--raised or sunk, embossments, flutings, mouldings, feet, handles, or applied figures. At one extreme come the earliest attempts at decoration in slip or clay, highly developed in the Gallo- and Egypto-Roman and Romano-British wares. The matured slip must be applied fairly thick to the still moist pot and then dried slowly.

Any work applied to dry shapes is liable to crack in drying or leave in firing. Probably the most effective use of slip is seen in the old tygs and dishes of Toft and others of his time.

The simple spotting and surfacing has been carried to perfection by the Martin Brothers, who have drawn largely upon the vegetable world for their inspiration. Roman Aretine ware shows finely executed reliefs of foliage and figures. The enrichment was probably worked on the original shape, a mould was then taken, and the vessel pressed. (See chapter on Casting.)

Wedgwood carried this method still further (too far, maybe) and used different coloured bodies. The reliefs, so finely modelled by Flaxman, were fired, and from them moulds of a very refractory clay were made, called _pitcher moulds_. The reliefs were then pressed and affixed to the vase, and the whole touched up by a skilled craftsman. A nave and unpretentious form of this decoration is seen in the stoneware and salt-glazed pottery of the eighteenth-century English potters and the jolly _Bellarmines_ of earlier times. Small dies were used in the Orion ware, the pattern being stamped into the clay. German stoneware and the _Gres of Flanders_ show sunk and relief patterns. Between the two extremes lies a rare choice of style.

This method of using patterns lends itself particularly to fine commercial work when used with the restraint seen in the best of the above-mentioned styles. To the craftsman it offers a welcome chance to enlarge his production, but he must be well equipped. It is easy to acquire the mere mechanism of commerce without its splendid technique. Finally, the further the relief is developed the less will be the appeal of form and the less the possibilities of glaze.

The next division is painting.

It is in this branch of ceramic decoration that the widest choice lies.

The scale ascends from the simple earthy colourants applied to the unglazed pot in the manner of the American Indian up to the splendid enamels of China and the sumptuous but sterile wonders of--shall we say--Sevres or Worcester. Much of the modern eighteenth- and nineteenth-century work is such a technical _tour de force_ that one hesitates to criticise it. But careful scrutiny will often show that the artistic difficulties have been undermined rather than overcome. Thus the frank frontal attack of the Persians on their absorbent ground or of the potters of Delft on their unfired tin glaze is never attempted, and probably never can be attempted in the factory of to-day.

The modern method of painting in fat oils on a prepared ground induces in any but the most accomplished a cramped and finnicky style. The best and really most beautiful results are seen in the delicate _vertu_ of the eighteenth century. Snuff boxes and ladies' knick-knacks exhibit the loveliest miniatures in an impressible medium. How far it is desirable to decorate pots with such pictures depends on the sophistry of the craftsman. (For, ever since painters were pampered by princes each erstwhile honest craftsman must needs try to turn painter!)

The Chinese who laboured with infinite patience upon their pots still seemed to preserve a spirit lacking in the works of their western imitators, and their avoidance of realism saved them from the many pitfalls that yawned for the Occidental.

The manner in which the Persians and Dutch preserved their freshness has been noticed already, but the encountering and surmounting of similar difficulties is at the bottom of most successes. A few of the methods of painting pots are here set forth, with some odd variants.

The colourants described under Glazes are also used for painting. Very finely ground and prepared, they are mixed with a flux or other vehicle and applied in various ways under or over the glaze. Simple colours can be made from the metallic oxides. They should be finely ground in a mortar well mixed with a little of the glaze with which they are to be used. This will do for the simplest work. For more subtle colours rather involved processes are necessary. The range of manufactured colours, both over- and under-glaze, is wide enough to suit all tastes, and when working on a small scale are infinitely to be preferred on the score of economy and dependability.

A method of painting entirely suited to beginners is as follows: A simple _palette_ is prepared with the colours ground upon a slab of gla.s.s. The medium employed is a solution of gum arabic and water, the colours being applied directly to the green shape with a brush. The difficulty of firing glaze on the raw clay deters any attempt at high finish, and the absorbent ground develops a desirable freedom and directness of touch.

When painted, the pot is dipped or poured in a transparent glaze and fired. The gum prevents the colour s.h.i.+fting during the immersion, but does not prevent the glaze adhering. This method can be satisfactorily employed on biscuit. More finish can be obtained and a richer glaze used without risk. Much skill and practice will be required to produce good stuff, as each touch, although not apparent before, will stand out distinctly and often disagreeably after the fire. The gum must be used sparingly; any excess will cause peeling and prevent the adhesion of the glaze.

For a still higher finish the biscuit is sized with a solution of gum tragacanth. This is smoothly applied until the pot is non-absorbent. The design, if elaborate, should be drawn upon the pot with a fine graphite pencil or, better still, India ink and brush. A common pencil is likely to show after firing, but the ink disappears entirely. The colours are then well ground and laid in with fat oil of turpentine or lavender oil.

To prepare the first oil, half fill a cup with pure turps, stand it in a saucer, and spill a little over the sides of the cup. After standing a little the fat oil is deposited in the saucer and the clear turps left in the cup. Long, flexible brushes holding plenty of colour are used and the fat oil thinned if necessary with clear turps. The colour should flow easily from the brush, being neither _tacky_ nor too fluid, and constant retouching is to be avoided. Keep all free from dust. Heavy, greasy-looking ma.s.ses should be sc.r.a.ped off and repainted, otherwise they will flake off.

When the painting is finished, the colour is _hardened on_; that is, the gum and medium are fired off in the kiln, a dull-red heat being sufficient. This does anything but harden on, however, and the pot must be handled very carefully or the colour will rub off. The glaze should now be gently sprayed on, and then the final fire is given.

Another way is to apply a very thin spray of glaze before hardening on, just sufficient to fix the colour. The pot may then be dipped or poured without risk. In each case the oily medium must be quite dry before the hardening on takes place. After the glost fire the decoration is fixed and unalterable. Where possible, a hard transparent glaze is best for fine work. A soft glaze will always run if slightly over-fired, and the result is the obliteration of all brushwork.

Over-glaze decoration is applied in a very similar manner. Turpentine, fat oil, and lavender oil are used: the turps to run the colour, the fat oil to stiffen, and the oil of lavender to r.e.t.a.r.d the drying. The colour must be applied evenly and thinly, thick patches being likely to peel or crack.

On hard glazes this process lends itself to elaborate effects. The hard and fast colours, the blues and greens, may be fired first, the delicate pinks and greys last. The whole effect may then be enriched with low-firing l.u.s.tres. These, when bought in bottles, are ready to use and are applied directly with a fine brush, then fired at a dull-red heat. The pot should then be quite finished; quite frequently it is.

_Pate sur pate_ or painting in relief colours is another process that has many attractive features. The colours have a clay carrier and are applied with a gum medium. Painted boldly with a certain amount of relief, this gives a rich enamel effect very suitable to simple figure decoration.

The full equipment of the painter will be as follows:

Colours, under- or over-glaze.

Brushes, tracers, and shaders.

A stick frame for holding the vase.

Turpentine and lavender oil.

A slab of ground gla.s.s.

A muller for grinding.

India ink and a colour slab.

A palette knife of horn for very delicate colours.

Some soft rags.

Before risking decent shapes in the fire, trials,--on biscuit for under-glaze, on glaze for over-glaze,--should be made repeatedly.

Graduated strips and stripes tartan fas.h.i.+on are the most useful and easily tabulated. To lay perfectly flat grounds some skill and practice are necessary. One method is to paint in the ornament or rather the s.p.a.ce it will cover with thick mola.s.ses or black treacle. This is allowed to harden and the background colour applied with a soft dabber. It must be ground fine with fat oil and applied very evenly. Then the tile or vase is soaked in water, which causes the treacle to peel off. The oil is allowed to dry and the piece fired. This fixes the background, and the decoration itself is next applied.

Pierced work if skilfully done is most attractive. The pattern may be incised on the "original," which is moulded, the design then showing in relief. This again shows as a slightly engraved pattern on each cast form or shape. Then with the aid of a fine-pointed knife or plaster tool the pattern is cut out and the edges are softened to take away any metallic look. The Chinese and Persians are said to have used rice seeds in some of their translucent effects. The seeds were embedded in the moist clay to form a delicate tracery. When fired, the grains disappeared, leaving holes which were completely filled with glaze.

The decorative possibilities of simple incised lines and plain slip additions have been hinted at already. The slip may be coloured red or brown with iron and manganese oxides or applied white to a coloured body.

Sharply incised lines may be filled in with colour stiffened by the addition of a little _hard_ clear glaze or China clay. Patterns may be dug out or stamped in and filled up with different coloured clays and the whole glazed with a coloured transparent glaze. Scraffito work is effective and not difficult. The green pot, tile, or dish is sprayed evenly with a different coloured slip, usually red on white. The piece should not be quite dry and the coefficient of expansion between the two clays as near alike as possible. The decoration is then sketched in and the background or the ornament itself gently scratched away to show the ground beneath. It is then fired, glazed, and fired again. All these processes have their uses and abuses, but they do not lend themselves readily to elaboration or realism.

[Ill.u.s.tration: FIG. 56--STATUETTE FOR A THREE-PIECE MOULD.]

CHAPTER XIV