There are lots of ways to decorate pottery other than glazing, from carving or making impressions in the clay, to trailing with colored engobes. You can combine multiple decoration techniques for unique and eye-catching designs.
Note: It can be a good idea to try out any new techniques or combinations on sample pieces of clay, so you can get a good idea of how the finished piece will turn out, rather than experimenting on a finished item.
Carving
Carving a pattern into the surface of the clay is one of the easiest ways to decorate it. This technique works nicely with glazes, which pool in the grooves. Or it can be combined with colored slips to create in inlaid patterns (more on this below).
Carving does not require any specialist equipment, you can use anything that will cut into the surface of the clay. Pottery tools like loops and needles can be used, or anything else from your surroundings, like knives, forks, toothpicks, etc. You can use a banding wheel to carve smooth lines around a wheel-thrown object.
Carving is usually undertaken when clay is at the leather-hard stage, as this is the easiest stage to work with. However you can also carve softer clay for a different effect.
Faceting
Faceting is cutting planes into the surface of a pot. It can be undertaken at any stage where the clay is still wet enough to cut, from freshly thrown, to leather hard.
You can use anything that has an edges sharp enough to slice through the clay. A clay wire tool, a knife, a cheese cutter, or a curly wite to create a textured facet.
Fluting
Fluting is a type of surface decoration made by carving away the clay to create grooves in a regular pattern, using a sharp tool.
Fluting can be carried out on soft or leather-hard clay. If the clay is still soft, loop tools can be used for deep rounded grooves. With drier clay carving tools (as pictured above) are a better option.
Impressing or Stamping
Patterns or shapes can be stamped or pressed into clay.
This is usually done before it is leather hard, as the clay needs to be a bit pliable to take an impression.
You can use almost anything to create an impression, from purpose-made texture-tools, leaves, seashells, doilies, or even corn cobs! You can also make your own stamps from clay or plaster.
Like carving, impressing works nicely with glazes, which pool in the grooves.
Perforating
Perforating clay creates holes that will let in light in a decorative way.
This is best done when clay is at the leather-hard stage. If you try perforating softer clay, it can collapse or warp. If the clay is too dry, perforating it may cause it to crack. Use a damp sponge to gently smooth the edges around the cut if necessary.
Use a sharp knife, clay hole cutter, or a drill to create holes or a pattern. It is important to remove the clay from the inner part of the hole, not just piercing a hole, as this can deform the clay.
Application
An application is a shape made out of clay and attached to the main object to decorate it. Think flowers, spirals, or borders.
Dry both the object and the pieces to be applied to the leather hard stage. Score the parts of each object that will attach, apply slip, and press the two pieces firmly together until attached securely. If not attached properly the applications will fall off once the piece is fully dried.
Wax relief
You can create raised patterns or shapes on your clay using wax relief. With this technique, melted wax (or shellac) is painted onto the leather-hard clay to create patterns or a motif. Then, use a damp sponge to gently remove the clay around the pattern.
The clay under the wax remains intact. Once the object is fired the wax will burn off, leaving the raised pattern on the finished piece.
Slip Trailing
A slip or engobe can be applied with a ball syringe or piping bag to add surface designs to your piece. Thick slip makes taller lines, while thin slip creates flatter designs. The slip can match with the base clay color, or you can make a colored slip, or engobe for contrast.
This method works best on leather-hard surfaces. Use a banding wheel to create even circles or swirls. Common designs include swirls, flowers, and abstract patterns.
Slip trailing pairs well with other methods. Carved areas can frame trailed designs. Glazes highlight the raised patterns after firing.
Inlay
This technique involves carving into the clay, then filling the void with a slip of a contrasting color, or engobe.
Carve a pattern into your leather-hard clay. Then, apply the engobe into the lines so that the carved lines are filled flush with the surface of the pot. Once the engobe is dry, scrape away the excess so that the surface is smooth.
Sgraffito
This techniques involves covering the clay object with an engobe of a contrasting color to the base clay, then once it is dry, scratching a design through the engobe to reveal the base clay underneath.
When the clay piece to be decorated is leather-hard, it should be coated evenly with a thin engobe. Allow the engobe to dry to leather-hard before carving. Use carving tools and/or metal ribs to remove the engobe to create your design.
The timing is key - the slip must be leather-hard but not too dry. Too wet and the lines will be messy. Too dry and it may flake off.
Sgraffito works best with clays without grog, as any texture in the clay can prevent the lines from being smooth.
Burnishing
Burnishing is a technique used to polish a clay object before it is fired. The process presses the clay particles together, smoothing them out. This was the method used to make vessels (semi-)waterproof in the days before glazes were used.
It is a simple technique, but does take time and patience. Note: burnishing will not work well for any clay bodies that have a high grog content.
You will need a hard smooth slightly rounded tool such as a polishing stone, or the back of a spoon. When the clay is at the leather hard stage, you use the tool to gently polish it until the surface is smooth and shiny.
Because the clay will return to its matte form if you apply water, you can paint patterns into the burnished clay using a wet brush.
