DECORATE WITH ENGOBES!

THE decorative possibilities inherent in the use of engobes are quite rewarding when approached inventively, with an eye to a full exploitation of the opposing aspects of the several techniques. Incising, brushing, inlaying, trailing, pouring, and reserving all have their special qualities which wait only to be recognized and used creatively.

Engobe and slip are the same material. The different words suggest different uses. Engobe is slip used for a decorative purpose. However, slip can be used decoratively without being called an engobe, as in slip painting and slip trailing. The word “engobe” generally implies covering the surface of the piece completely or in large areas as when used with paper friskets or for sgraffito.

Engobe, like slip, is a fluid mixture of water and clay or other ceramic materials. It may consist of a single clay or of several ceramic materials properly proportioned. For contrast, the engobe is always a different color than the clay body upon which it is used. Engobe is often applied to the piece when it is either leather hard or dry. In rare cases an engobe may be applied to a bisque piece; in the wet trailing method it must be applied to the moist clay. In each situation the right type of engobe must be used, and the exact method of using it is established by trial and error.

In the total planning of a decorated pot we cannot overlook the body upon which the slip is used nor the glaze with which it is covered, but our point of departure now is the slip or engobe itself. Starting with any given idea, each of the techniques illustrated here will produce a result distinct from the others. Let's take a single subject as the basic idea, fish, for example, and see how each one of the decorative methods has suggested to one person its own special way of saying “fish.”

SLIP PAINTING this bowl was done with a Japanese brush using slip made more unctuous and brushable than usual by the addition of glycerine and Karo Syrup. Because a damp clay surface is more receptive to slip the bowl was thoroughly sponged immediately before painting.

A good deal of experimental practice is necessary to discover what kind of strokes and other marks the brush can be counted on to make; and, the design chosen should be painted freely.

In slip painting, filling in a predrawn outline is not only sterile in concept and result, it is an insult to the brush and an embarrassing revelation of aesthetic illiteracy in the artist.

SLIP TRAILING produces a thick, fluid-looking line. The flow of slip through the tube is only partially controlled by the hand pressure on the bulb. Once the tube is down on the surface the continuous flow of slip leaves no time for pondering. The slip flows whether the hand moves or not. A quick movement leaves a thin line, sometimes with skips. Momentary hesitations are recorded by an extra thickness at the beginning of a line and where the line doubles back on itself.

The demand of this method for continuous action extracts from the artist, almost by force, an expression as personal as handwriting.

WET SLIP TRAILING, a fascinating English slipware technique, has not been exploited by contemporary American potters, and yet it seems uniquely capable of producing a contemporary expression. Its excitement stems from the lack of all but the most rudimentary control. One never knows how it will end.

For this bowl, a flat disc of moist clay was laid on a pallet, white engobe poured over it and allowed to drain off. On the moist clay the engobe remains wet and mobile for a long time. Black slip was then trailed onto the wet surface. A certain distortion is inevitable as the two slips mingle and settle to a common level. Exaggerated distortion can easily be gained by shaking or rapping the underside.

On this bowl the tip of a small brush was drawn through the upper fin and around the eye and also produced the whiskers.

When the slip has dried enough to become firm, the flat disc of clay is given its form in a hammock mold or in a bisque bowl or over a drape mold.

MISHIMA is an inlaying technique attributed to the Koreans. The design is first incised or imprinted in the soft or leather hard clay. Second, slip is carefully brushed into the depressions so formed and unavoidably over most of the surface, too. After drying comes the third step, which is scraping the surface clean leaving the slip only in the incised or imprinted marks.

The upper fish was completely incised and the body of the lower fish was imprinted with a V-shaped stamp made of bisque. A rigid incising tool is more closely related to our Western writing instruments than to the brush. So most of us may feel more at home doing mishima or sgraffito than using the brush or slip-trailer.

Richly textured, brocade-like effects can be developed by all-over imprinting with simple stamping tools made of bisque.

SGRAFFITO is easy to do, and is a favored technique for intricate line patterns. A variety of tools will produce a stimulating contrast in line quality from broad gouges done with a wire loop to thin, pen-like lines made with a needle point.

Sgraffito is essentially a kind of engraving technique and derives its name from the Italian word meaning “scratched.” The surface of the piece is first coated with engobe. When this is firm, but still soft, the design is cut through it revealing the body beneath.

PAPER FRISKETS are a kind of stencil or mask. For use under engobe, the friskets are saturated with water, then laid on the dry clay surface. The engobe is brushed over the friskets and the entire surface in this case. As soon as the engobes can be handled without damage the friskets are carefully peeled off with a needle-sharp point.

Friskets yield an extreme precision of shape unobtainable in any other way. Small, simple paper units will lie close to the surface much better than large, complex shapes which wrinkle and buckle. Complex designs can easily be built up by combining a number of small units.

RUBBER RESIST can be thought of as a liquid frisket brushed directly on the dry clay surface. The liquid rubber dries in a few minutes and the engobe is brushed over the surface. When the engobe is firm enough to be handled without damage the rubber is peeled off revealing the clay body beneath it. The effect is the reverse of slip painting, brush strokes in body color against a background of engobe color.

While very similar to the wax resist method in which melted or a wax emulsion is brushed on, the use of rubber has several very definite advantages. It works more easily from the brush than melted wax. It does not deteriorate in the jar. It eliminates the need for bisque firing to burn out the wax. And not least, the liquid rubber is immediately obtainable from several souces of supply.

TOOLS AND MATERIALS used in the foregoing decorating techniques are easily obtainable. For slip trailing, a simple arrangement can be made from a balloon and a medicine dropper, as shown in the illustration.

The balloon can be filled with a fluid slip simply by pouring a thin stream into its mouth. For a pasty slip a small funnel is helpful. The small rubber bulb is removed from the stopper and the balloon is firmly attached in its place with a rubber band. Save the rubber bulb, for it makes a tight-fitting slip-on cap for the open end which will prevent evaporation for several weeks.

With a gas flame the tip of the glass tube can be softened to change the size of the opening. In use, the balloon is a limp container which never sucks air back into the slip as do syringes. Such a situation would interrupt the flow of slip.

A personally selected variety of sgraffito tools provides an automatic contrast in line quality which is more exciting visually than the use of an unchanging line.

Left to right are two rather broad loops of piano wire bound to wooden handles; a bobby pin for a smaller loop; a small steel welding rod hammered flat on the end and filed to a smooth, rounded blade; and two more welding rods ground and filed, one bluntly pointed, the other needle-sharp. On the extreme right is a piece of hack saw blade, its round end notched with a needle file. (This was used on the mishima bowl border.) It easily incises a multiple line over curved surfaces. The last one is another welding rod hammered flat on the end and filed to a smooth, wide-angle point. The width of its incised line varies with the pressure applied.

Friskets are best cut from newspapers with a sharp knife or blade. Cutting through several layers of newspaper produces six or eight units at a time. They are saturated with water and laid dripping wet upon the clay surface. The water holds them down until the engobe can be applied. When many friskets are applied the first ones sometimes have to be remoistened quickly with a wet brush just before engobing. A needle-sharp point is used to prick up a corner of the frisket to peel it off.

Brushed on the clay, rubber latex dries to a nearly transparent film to which the engobe does not adhere. Its dully glistening surface can be seen in the photograph.

Customarily sold for making flexible molds, the latex is a rather thick, white liquid. It flows from the brush more readily when thinned a little with diluted ammonia. It is very important that the brush used be immediately and thoroughly rinsed clean in diluted ammonia, because if allowed to dry in the brush the rubber cannot be removed.

A corner of the rubber film is pricked up with a needle-sharp point, and the rest is peeled off with a slow firm pull.

After trying all these methods and visually tasting their different qualities individually, one begins to think of combinations of one with another. An enriched visual orchestration can be achieved by using slip painting with sgraffito, mishima with slip trailing, two colors of slip super-imposed each with its own pattern in rubber resist. The possibilities multiply astoundingly. We become impatient with our pedestrian hands as the mind races like groundfire through the permutations of body, slip, glaze and technique. Body textures smooth or coarse, sparked by slip stippled or smeared or brushed, light upon dark, dark upon light, speckled, streaked. Glazes that flow, that pool, that are clear or murky, revealing, obscuring, enhancing, and all of it spiced with color. Slip sensuously brushed, crisply incised, regimented with friskets, trailed with abundant wetness. These are the potter's alphabet. You and I need only the courage to use it.