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.
