Effective decoration is the essence of fine ceramics craftsmanship.Practice this variety of techniques.

There are many effective techniques A by which you can decorate the wares you produce in your ceramic workshop.Decorations may be applied upon soft clay by incising, inlaying and embossing; upon dry clay and bisque-fired clay by color, either under the glaze or with no glaze at all; in the glaze by the use of colors or colored glazes; or over the glaze with colors and enamels and decalcomanias.Each of these methods has its own special features.Each has its own possibilities and limita­tions which should be mastered.

The simplest, but not necessarily the least effective, form of decoration consists of scratching a design in the model while it is still soft.All that is required in the way of tools is a scratch-point, a darning needle, a toothpick, or any other pointed object which can be used as a stylus.The clay should be leather-hard when you incise your design.You can make just a line drawing, either naturalistic or abstract, or you can bring the design out in relief by cutting away part of the background.

Photos courtesy of Ceramicbrome unless otherwise credited

To obtain fine white lines seen on the finished piece a sharp-pointed sgraffito tool is used, as at right.Exert firm pressure on tool to scratch through thin coat of color to greenware itself.This technique is easy, and any mistakes can be simply corrected by sponging over the scratched areas with the original color any number of times.

The next logical step is sgraffito decoration.To do this, cover the whole piece with a coating of contrasting colored slip.Then carefully scratch a design through the outer slip, exposing the clay underneath.

Use a large brush to paint the slip on the leather-hard unfired clay.Some ceramists prefer to dip the piece into a large container of slip, but this is generally not practical for the hobbyist because of the large quantity of slip required.It may be advis­able first to lightly sketch the design to be etched in pencil.When you are done carv­ing the sgraffito design, let the piece dry thoroughly.Bisque-fire it before applying a transparent glaze, and then fire it again.

Far left, decorated greenware plate has been fired in kiln at 1850° F (cone 06).Upon removal, finished plate is ready to use.First step in decorating plate is to mask larger areas of design which are to receive no color during process.Masking compound, applied to cleaned greenware following rough pencil sketch, is water-soluble and normally applied by brush: it may be used on artware, porcelain green­ware or bisque, and after glazes are ap­plied the compound peels off.Here, the border and center fruit areas are masked.

With water-based color, sponge is used to dab desired color on the entire piece of greenware.Color won't penetrate masked-off areas, and is kept at even consist­ency by adding water until it's easily put on with sponge without running or clotting.Greenware is more fragile than fired ce­ramics, so support it from underneath with hand rather than holding it at the edges.

Above, alter color is sponged on and design scratched in, masking compound is removed simply by pricking the sur­face with sharp point of tool and then peeling off the masking.Don't leave masking on for longer than six hours.

Final decorating stage is shading of fruits, and internal shading effects.This is achieved by using same color as in background, toned down with water, lust brush on, and to change a brush stroke employ water-dampened sponge.

Satisfaction and accomplishment are your rewards when you open the top of the kiln to inspect your finished and successful pieces.Kiln shown is low-cost and small; larger models which hold sizable pieces cost around $45.

A similar sgraffito method is this: Incise your design before adding a coat of colored slip.Then paint the slip over the design.Finally, scrape the slip off the surface, leav­ing only that which has settled in the in­cisions you scratched, so that the lines of the design are contrasted with the clay body.Wonderful effects can be accom­plished with experimentation.For example, all the outer slip need not be removed, but instead left here and there on the piece as colorful highlights.Usually, the slip is not painted over the entire surface but only over the area which has been incised.

The use of colored slip need not be re­stricted to sgraffito work.On the contrary, slip painting—otherwise known as engobe decoration—is employed to obtain many types of wonderful designs.

Any light colored slip, or engobe, can be tinted by the addition of metal oxides, stains or underglaze colors (these are ex­plained later in this chapter), then used to paint designs on leather-hard or dry objects.One color may be placed over another color and shaded or blended into harmonizing designs.This can often be combined beautifully with sgraffito work.

You can also use engobes for slip-trail­ing.Fill a small rubber syringe with engobe and squeeze the slip through the nozzle in a thin line while tracing a design on the surface to be decorated, as a pastry chef squeezes out cake designs.By means of slip-trailing, you can shape delicate flowers and leaves of clay, just as they are formed of cake icing in a bake shop.For a gor­geous mosaic effect, an irregular crisscross, or checkerboard, patterns can be drawn and filled in with contrasting colors, then glazed with a transparent glaze.

If you have admired the elegant wares made by Wedgwood, here is an easy way to attain similarly good-looking results.Take a mold which has a cameo or floral design and brush slip on this portion of the mold.Now take a different color slip and pour it into the mold as usual.When you remove the castware from the mold, the two colors of slip will have hardened into one piece, but the main body of the piece will be one color and the relief design another.

It is also possible and worth while to pour a decorative mold in one color slip and the main body of a model in another color.This is the way in which genuine Wedgwood is manufactured.The white figures which stand out in relief against the famous blue background are separately cast.Then, when leather-hard they are slip-glued in place on the piece to be decorated.Such separately cast ornaments are called sprig­ging.With a little practice, you should be able to apply sprigging to your own cast-ware without difficulty.

Most colored slip can be purchased from ceramics suppliers, although it is not too complicated a matter to mix your own colors.Many engobes are naturally colored clay.The temperature to which an engobe is exposed will often affect its color tre­mendously.Victorian clay, for example, turns to a rich mahogany at medium-high temperatures, while at low temperatures it becomes a lustrous black.Dalton No.93 becomes brick red in the kiln, turning darker as the temperature mounts.If you learn the effects of heat on the engobes you use, you will be able to control their color and obtain any shade you desire.The best way to learn is to experiment, keeping records of your results.Next best, perhaps faster but certainly less interesting, is to study a technical treatise on the chemistry of ceramics.Of course, an instructor or supplier will be happy to answer specific questions about any clay.

To make your own engobe colors, you will have to add small quantities of me­tallic oxides to the slip.Keep in mind that one-third of slip by weight is water.The percentages given here for the amount of oxide needed to produce the desired color are based on the dry ingredients of the slip by weight.In other words, if you had 100 grams of slip and wanted to tint it blue, 66% grams are comprised of dry ingredi­ents.Add three percent cobalt oxide (see chart), or two grams, since three percent of 66% equals two.

Divide the total weight of slip, exclud­ing the vessel in which it is weighed, and divide by two-thirds before figuring the amount of oxide you will need.Mix the oxide and the slip thoroughly and strain several times through a 160-mesh screen.

The combinations and different types of coloring agents are virtually unlimited, but on the next page is a basic list of oxides, percentages which should be used, and the colors they will produce.

This list, complete as far as it goes, is designed only to illustrate how colored engobes are made.Many oxides are capable of imparting more than one color, depend­ing upon how much of each is used, in what combination with other oxides, and at what temperature they are fired.Iron oxide, for instance, can be utilized to obtain green and red engobes, as well as brown and black.Copper can be used for red, green and blue engobes.

Interesting sponging method uses rotating elec­tric table to spin greenware as color steadily is "wiped" from inside to outside of plate, to leave the spiralling lines heavier in the center.

Here is reverse effect, with heavier area around outside.Plate is lifted from the table and an additional design in a darker color is superim­posed by brush on previously applied underglaze.

Chromium oxide imparts a hue of green, pink or red.Silver oxide is used in gray and yellow engobes.Until the advent of the atomic bomb, uranium found its biggest commercial use in tinting en­gobes yellow, green and ivory.Today understandably enough, it is not available to ceramists.But the same colors can be produced with other oxides.

There are several other substances be­sides metallic oxides which can be used to color slips and engobes.A dried and pow­dered clay such as Albany can be mixed with a lighter slip to turn it a reddish brown.Cadmium sulfide will make an engobe turn yellow, as will lead antimonate.Orange can be produced by mixing in lead chromate.Sulfur is useful for obtaining an amber hue.Various gold compounds will impart colors of red, rose, purple and gold.

Engobes should be brushed on the sur­face evenly and to the approximate thick­ness of one-sixteenth inch if a solid color is desired, otherwise there will be the possi­bility of uneven color after the glaze-firing.If a glaze is put over this slip, it will prob­ably produce an uneven color after it is fired if the slip is uneven in thickness.If slip is applied too thickly, however, it will tend to crack and break away from the surface of the object.Whenever you use one clay over another you should be certain the fire shrinkage is the same.Generally a dark-colored engobe or slip is applied to a lighter clay body, although the reverse can be done with topnotch results.When a light engobe is brushed over a dark clay, the latter is partially seen through the coat­ing in the thinnest places.Many ceramists thus obtain fine shadow effects in their slip-painted designs.

Engobe coloring is frequently used to color the inside of a ware with one shade and the outside with another.Variations can also be made by adding a colored de­sign and leaving a band of natural clay to show them.Then, with one application of transparent glaze, either gloss or matte, you will give the appearance of an interestingly constructed and decorated piece.By glazing only a slip-painted design and leaving the rest of the piece to fire as bisque, you can produce a ware which seems to be inset with jewels.

Simple but very effective decorating technique is that of stencil.First, piece of greenware is covered with paper stencil, then colors prepared on board are dabbed into open areas with sponge.

Stencil removed, design is completed by brushing color on to accent the appearance.From start to finish of this design took only I12 minutes— and the iinal product is both pleasing, unusual.

It is extremely difficult to separate the glazing process from that of decorating, since these two steps so often overlap.The most commonly used forms of decoration are underglazing and overglazing.Under-glaze decoration includes any ornamenta­tion that is applied to ware before it is glazed and fired.This includes slip-paint­ing and sgraffito carving or any color painting done on greenware or bisque.For example, if you were to paint a floral de­sign on a piece of greenware, then cover your work with a clear glaze and fire, it would be a typical form of underglazed decoration.

Such ornamentation applied after the ware is glazed is called overglaze decora­tion.The two most popular forms of over-glaze decoration are hand-painting with overglaze colors and the use of decalco-manias, or decals.

The main difference between underglaze and overglaze colors is that the former are not fusible.That is, they will not adhere to the ware even if fired.They will still be a powder and will rub off.Glaze is neces­sary to hold the colors in place and keep them from smearing.Underglaze colors consist of one-third metallic oxide, one-third slip and one-third glaze.Make certain that the slip in the paint is the same clay as that in the piece to be decorated so it will have the same shrinkage in the kiln.The glaze in the color must also be the same glaze that will be used over the underglaze paint.Some ceramists prefer to add the glaze after the color has been applied to the greenware.Either method is satisfactory.If you do not want to mix glaze in the orig­inal color formula, you can spray a thin coating, over the decoration with an atom­izer.

Underglaze colors can be made in the home workshop, but it is much more prudent and timesaving for the novice to buy them already prepared.Virtually any desired color can be bought at a reasonable price.By mixing the commercially pre­pared colors yourself, your paint palette can include every color on the spectrum.Always read the directions which come with the paints—and then experiment to your heart's content.

When using underglaze colors on bisque ware, rather than greenware, no slip or glaze should be added to the color mixture.This is because the bisque has been com­pletely preshrunk in the drying and firing processes and the slip in the colors has not.Unequal shrinkage would thus result, causing the paint to crack and peel off.

Use ordinary water-color brushes to apply underglaze colors.

Plate pictured below and at left is decorated with combination of ce­ramic crayon and clay slip.To start, plan out design beforehand and make crayon portion first; to add slip, fill a small rubber syringe (here, balloon and medicine dropper tube substituted) and squeeze steadily.

A good selection of brushes would range in size from No.00 up to Nos.11 or 12.Both pointed-tip brushes and flat brushes will prove useful.The greenware should be completely dry be­fore it is decorated with underglaze colors, otherwise there is no absorption and the color will be too thin on the surface.Keep the brush well loaded with paint and let the color flow on the piece.Never drag the brush across the clay, since brush strokes will show through the glaze after it is fired.It is better to paint over solid-color areas three or four times to make sure the color has been applied heavy enough.It is all right to paint thin color over color.

Underglaze decorations can also be ap­plied to greenware with a spray gun.Many commercial potteries use this method.Cut a design in a paper stencil and place it against the surface to be decorated.Using a thin spray, aim the gun at the openings in the stencil.Any number of colors may be used and many different shading effects can be accomplished.For most hobbyists, how­ever, the cost of spray-gun decorating is prohibitive.You will need such equipment as a spraying booth, turntable, spray gun and compressor.

For line designs on flat pieces, such as tiles and trays, you can effectively apply underglaze paints with a small rubber syringe.

After basic design is coated with melted paraffin or wax.contrasting colored- slip is brushed over entire surface of ware; this is called "wax-resist" method since clay slip will not adhere to the painted surfaces and wax will fire-out in kiln.Slip mixed with powdered engobes will vary colors.

Photos from "Craftsmanship in Clay"

With any scratching or sgraffito tool, incise your design to depth of 1/32 to 1/B4 inch; don't make all lines of same width and never go over a line.

Using thin rolls of clay, drape them on ware in approximate or permanent position; design can be worked into the clay rope with a modeling tool.

On round pieces it is much more difficult to control the flow of color.Several different colors can be kept at hand in dif­ferent syringes.For best results, apply the paint freely in swirls and straight lines.If you wish, of course, you can work out your design beforehand, although this is apt to make the finished pattern look too stiff and mechanical.

It is possible to achieve lovely decorative effects by combining underglaze colors with colored glazes.But a clear glaze is usually selected if underglaze paint has been used.

There is a distinct difference between underglaze and overglaze colors.Overglaze paints, for the most part, are oil-based paints.They are applied after the piece has been glazed and fired.After the decoration is placed on the glaze, the piece has to be fired again at a low temperature to make the decorations permanent.

Overglaze paints can be obtained from any ceramics supply house.They can be easily combined to form new, secondary colors on a glass or porcelain slab.Add a few drops of turpentine to the paint and mix before using, with a palette knife, until it is smooth.Too much turpentine will make the paint too thin.Some potters argue that fat oil is a better paint thinner than turpentine.A better grade brush is re­quired for overglaze colors, since they must be cleaned in turpentine after they are used.This will cause a cheap brush to stif­fen and fall apart after it has been used a few times.A sable-tipped brush is recom­mended.Do not worry if loose bristles are pulled from the brush and remain in the paint while you apply the color.The hairs will burn away in the kiln and no trace of them will remain.

Below, embossed or hand-applied clay bas-reliefs made from a press mold by the "figure maker" are being applied to ware by the ornamenter.Surface of clay ware is moistened with water and ornament is fixed by skillful pressure of finger.A sensitive touch is necessary to avoid ac­cidental marring of fine ornament detail.

It is important to measure out by weight all of your dry powders, and see that they are combined and mixed in a mortar and pestle very thoroughly.

When you are finished painting the de­sign on the glaze, let the paint dry before firing.To develop deep, rich, jewel-like colors, you will have to paint on one coat, fire it, and then paint on another coat of the same color and fire again.This can be done many times until you have achieved the color you are looking for.Liquid gold and silver can be painted over other colors after they have been fired: apply the gold or silver and fire again.

Overglaze colors and gold and silver have very low firing temperatures.Some will burn off at 1000 degrees Fahrenheit.Most, however, require a temperature of approx­imately 1300 degrees to mature properly.If the kiln does get too hot, no permanent damage is usually done.Most of the over-glaze colors will merely burn off and dis­appear.You can then redecorate the piece and fire properly.Many ceramists over-fire a piece on purpose when they wish to change or correct a design.

Decalcomanias, or decals, are used ex­tensively as overglaze decorations by com­mercial potteries.The designs are printed in color specifically prepared for use in ceramic ware by transfer.Decals can be purchased from supply firms, and most come complete with directions.First coat the glazed ware with a sizing of balsam and turpentine.Allow the sizing to dry until it is tacky.Place the decal against the tacky surface to which it will adhere.Dampen, then remove the paper, leaving the design on the ware.Firing will make the decora­tion quite permanent.

Decals can also be applied to bisque, or unglazed, ware.Dilute regular decal varnish with 40% to 50% turpentine and spread a thin coat on the surface of the bisque ware that is to be decorated.

When the varnish has become tacky, lay the decal in place, face down.If the decal has been printed on duplex paper, you must first remove the tissue from the heavy backing paper.Once the decal is in the proper position, rub with a stiff brush which has been moistened.Remove all creases and bubbles.Apply water until the tissue paper floats away.Never pull the paper.

Fast overtaking these varnish-mounted decals in popularity among hobbyists are watermount decals, a more recent innova­tion which are printed with a ceramic over­glaze andj merely requires the use of water for transferring.Until these watermount decals were introduced, few home-studio ceramists used decals for decorating their wares.The method of application is com­paratively simple.Any glazed surface is satisfactory.Before applying the decal, make sure the ware is free of all finger­prints and other greasy marks.

Cut the individual decal out and im­merse in water for about 20 seconds, or until the clear film is free to slide from the backing paper.The design is then placed in position on the ware, face up, and the backing paper is slipped out from under the color film.Smooth down with sponge or your fingers, pressing from the center toward the edges.In this way remove all excess water from underneath the surface of the decal.Decals must adhere perfectly to glazed surfaces pr tiny holes will burn in the pattern.Dry thoroughly before fir­ing, at least 24 hours.•

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