FIRING.
When the piece decorated is thoroughly dry, it should be fired at a temperature sufficient to make the body durable, and at the same time to perfectly fix the colors of the painting, so that there may be no danger that the glaze will cause them to run in the final firing. This latter defect may also result from an excess of glaze, and where it exists only in a very slight degree, produces a melting softness which is very pleasing. This effect is, however, so likely to be exaggerated to the ruin of the work that it is best not to run any risk of the kind in firing, and to depend upon the painting alone for the harmonious blending of the tints.
The temperature at which the work is to be fired, must, of course, depend upon the qualities of the clay of which the piece of ware is made. As has been said before, this clay should be one that does not require an excessive degree of heat in firing. The exact degree can be estimated by the potter who understands the requirements of the clay which has been used in the manufacture of the particular piece of ware in question. It may be said that the temperature at which Rockingham ware is fired is suitable for this work, and that a glaze such as that used upon that kind of ware can be used with good results. It is possible to have a glaze so adapted to the body of the ware as to prevent it from crazing, and yet preserve the brilliancy of the colors.
CHAPTER V.
MODELING IN RELIEF.
Under this head may be comprised the decorative modeling of figures and other designs upon pottery, in various degrees of relief. First, we have figures in relief forming decorations upon vases. These, as well as other designs in high relief, belong properly to the domain of sculpture, and the methods of producing them do not vary essentially from those in use in that art. The final process in this case is the firing, instead of the casting in plaster and cutting in marble.
Of the methods of producing floral designs in relief, a few suggestions may be of use. These, as well as the painting described in the previous chapter, must be executed when the body of clay, to which they are applied, is very wet, and the applied clay must in this case be, as nearly as possible, in the same condition. If the clay is not in the proper condition, the work will crack in drying.
The vase which is to be decorated being in the right state, a lump of clay, having the plasticity necessary for modeling, is procured. This may be of C. C., a deeper cream color, or red, according to the color desired. White granite is not plastic enough, and is, besides, liable to crack in drying. But of all white clays, parian forms the most beautiful substance for this kind of modeling. Leaves and petals of flowers can be shaped from pieces of clay, which have been flattened to the required thickness, either by pressing upon a slab of plaster of paris, by means of a weight, such as potters use; or, if the work is not on a large scale, the clay can be shaped in the palm of the hand. The forms can then be cut with a sharp modeling tool. If there is more moisture in these pieces of clay than in that which forms the body of the vase, they should be allowed to remain a short time upon a dry plaster slab. The plaster will quickly absorb the moisture in the clay. When ready, the pieces can be placed in position on the vase, the places where they are to be applied having been previously washed with clay and water (technically called “slip”), or with glaze water, to make them adhere. Stems are made by rolling pieces of clay between the palms of the hands, or upon a flat surface of wet plaster or wood. They are afterwards allowed to dry, and when in proper condition, applied in the same manner as the flowers and leaves. Delicate touches may be put in with a brush dipped in clay, of a proper consistency for painting. The forms of the design can be shaped and finished after they have been applied to the vase by the use of modeling tools, and, finally, with a camel’s-hair brush. The design may also be brushed over with a sponge, moistened with water, which will also be found very useful in restoring the smooth surface of the ground, if it has been injured in the process of modeling.
After the modeling has been completed, the work should be gone over with a modeling tool, and in places where a mass of clay has been attached to the surface, the edges should be under-cut. This will prevent cracking. If this precaution is not taken, a crack thus produced may extend into the body of the vase and render it unfit for firing. Where a large mass of clay occurs in the modeled design, it is better to hollow out the projection from the inside of the vase, to prevent the cracking or warping of the whole in firing, caused by the unequal thickness.
Cracks, which may appear in drying, should be filled, or, if possible, be pressed out with a modeling tool, before the piece is fired. If the crack is so deep that it is necessary to fill it, the place should be cut open with a modeling tool, moistened with water, and filled with clay, as nearly as possible in the same condition as that upon the vase.
Flowers can be modeled in parian clay upon a creamy-tinted ground with good effect. Various colors of deeper tinted natural clays, or clay which has been artificially colored in the body, can be used as the ground of such decorations. Light grounds are sometimes colored after the first firing, in the biscuit; or a ground can be painted in the method described in the previous chapter, while the vase is soft, and the modeled decoration can then be applied instead of the painting.
Decorations of this character in high relief are frequently colored in natural tints, either under the glaze, in the biscuit; or over the glaze. The taste of this manner of finishing relief-work is somewhat questionable, and the same objection might apply to it as to colored sculpture. That it has received the sanction of the best factories in the world is no proof of its being in accord with correct taste, as the many (artistic) atrocities of Dresden and Capo di Monte testify. Some of the later Haviland faience, however, having a ground in the usual style of that ware with decoration in high relief, colored with subdued tints, harmonizing with the grounds, is so artistically done that one can hardly think it open to this objection, although it can not be considered an improvement upon the earlier work of this establishment in which the colored decorations were simply painted upon the surface.
It is only to the use of colors which imitate those of nature upon modeled decorations that there could be any objection. Relief-work may be conventional in its form, or colored conventionally, in one color or many, or gilded, with perfect taste. The latter method produces a fine effect, but, to make it successful, the color of the ground should be well chosen, and the design simple in form and not too much detached from the surface. The gilding looks best when left unburnished, and should only be rubbed enough to give the effect of dead gold.
Next, we have applied designs in low relief. These are made in several different ways, according to the effects desired. Work of this kind is more commonly executed by the method used in the production of Wedgwood-ware. The designs to be applied are first modeled in clay. Casts are then taken of the models in plaster of paris. Clay of the kind desired for the relief designs is then pressed in the mold and the edges trimmed off. The design can be removed from the mold by the aid of a flat, steel instrument, with a short, broad blade; or a palette knife, which when pressed upon the clay adheres to it and detaches it from the mold. It can then be transferred to the piece of ware to be decorated, to which it is made to adhere by the use of “slip,” as described before.
This method is very useful, indeed, indispensable in the manufacture of such wares commercially, when the same designs are to be repeated many times, but it is hardly to be recommended for artistic work, except for conventional designs, borders, etc. This method of casting the forms in a mold may be useful, however, in the reproduction of leaves of intricate outline, which can be made of various sizes, and, from the plasticity of the clay, can be infinitely varied in position according to the taste of the worker.
When objects of delicate and intricate form, such as threads, spider’s webs, nets, and sometimes leaves, are to be represented in work of this character, it can be accomplished by dipping threads, or nets of cotton, or, if leaves, the natural leaves themselves, into “slip.” The clay adheres to the threads, or forms, and after it has set sufficiently, they can be placed upon the object to be decorated. On firing, the substance inclosed within the clay is dissipated and the clay only, remains. Some very wonderful and beautiful effects may be produced in this way; but, as these delicate forms are necessarily very fragile, especially if much detached from the surface, they are only suitable for articles intended solely for ornament.
Designs in low relief can also be applied with the brush in the forms desired, which may afterward be shaped and finished by the use of modeling tools, or, when dry, carved with steel instruments. This latter is said to be the method by which M. Solon executes his exquisite designs in fine white clay upon ware which has been colored in the body. One of the greatest beauties of M. Solon’s work is the transparent effect produced where the clay has been left so thin as to show the colored ground through.
Work in the very slightest relief can be done with the brush alone. Care must be observed in this, however, that the application of clay is not so very slight as to produce complete transparency upon firing. By a judicious mixture of work in which the clay is so heavily laid on as to remain opaque after the firing, and of that which is applied so thinly as to become transparent, very delicate and beautiful effects can be produced by the use of white clay upon colored grounds.
The colored grounds in the Wedgwood and Solon ware are produced by the use of a fine clay body, which has been artificially colored throughout, which, in the case of Wedgwood, is finished by a very slight glaze, and in the Solon ware, by a full glaze, by which the transparent effects of certain parts of the work are brought out. The colors used in the body of these wares are blues, dark greens, and olives, and also black. Where it is not possible for the amateur, for whom these hints are written, to obtain such wares for decoration, very pretty work can be produced, as has been mentioned before, by the use of a body of naturally colored clay upon which white or a light-colored clay can be applied.
Relief-work can be finished with a full glaze, a very slight glaze, or can be left unglazed. As a general thing it may be said that the modeling in a design in high relief will look best with but a slight glaze, or none at all. The slight glaze is called by potters a “smear” glaze, and is effected by firing the work in a “seggar,” which is glazed upon the inside. The unglazed ware absorbs enough glaze from the glazed surface to give it a semi-glazed appearance, which is very pleasing. Work in partial relief, as well as articles in full relief, can also be finished by the application of colored glazes. This is the method by which the ware known at the present time as majolica is produced. Blue and green glazes of this kind are frequently to be obtained in potteries in this country, where they may be applied to work which has been modeled. Other colors in majolica glazes are to be had from the dealers, and if the colors desired can not be applied at the pottery, the artist can apply them with a brush in the same manner as paint is used upon the biscuit. The effect of work of this kind can also be enhanced by gilding put on over the glaze.
CHAPTER VI.
INCISING AND CARVING IN CLAY.
These are two of the simplest as well as most effective methods of decorating pottery. We will treat first of incised work in clay.
The piece of ware to be decorated must, of course, be in the “green” state; not too wet, yet not dry enough to be brittle. An outline drawing can then be executed upon its surface with a pointed modeling tool, not too sharp, and perfectly rounded at the point. If any burr is thrown up in the course of the lines, it must not be brushed off until the piece has become partially dry. The drawing can then be brushed over with a stiff camel’s-hair brush, leaving the lines free. These lines can now be filled with dark (under-glaze) paint (black is best), mixed with a little gum arabic and water. In going over the lines some of the paint will extend over the edges; this can be scraped off, when the clay is dry, with the edge of a sharp steel blade, two or three inches long, held between the fingers and thumb. A broken knife-blade will do for the purpose. This scraping must be very lightly and carefully done, to avoid injuring the surface of the ware. The surface may afterwards be rubbed over with the very finest sandpaper, when entirely dry.
The finish of this work must not be a full glaze, but the “smear” glaze, described in the last chapter. A full glaze would fill up the lines, and so injure the appearance of the work. In order that the black lines may be effective, the ground of the decoration should be rather light in color. The best colors for the body of wares to be decorated in this way are light cream color, or a mixture of cream color and red clay, producing a light brick-red; or, if they can be procured, any light colored clays which have been artificially tinted in the body. A colored ground for this work can be procured by having the piece of ware dipped in colored slips. The design is then incised upon the surface, after it has become dry enough, in the same manner as before. The lines are cut through to the body of the ware beneath, showing a color contrasting with that upon the surface with good effect. Work of this kind is also executed upon stoneware. That of Miss Hannah Barlow will be remembered as an instance of incised work, in black lines, upon a red or light brown body. Incised work also appears upon the Lambeth stoneware. It is here used upon grey stoneware, with raised dots in white, and colored with blue glaze. Incised decorations can also be executed upon earthenware in this way. White ware may be used, and the design drawn upon it in the “green” state. The piece may then be finished with colored glaze, which sinks into the depressions formed by the lines, and so gives them a darker color than the rest of the surface. Carved work can also be introduced with good effect as an accessory to incised work, and a few words as to this kind of decoration will now be in place.