Sgraffito on clay is a decorative technique where a layer of colored slip or underglaze is applied to the surface of the clay, and then designs are scratched or carved through the layer to reveal the clay body beneath. This creates a contrasting image or pattern.
It's a simple yet effective way to add detail and texture to ceramic pieces. The basic idea is to subtract material (the slip/underglaze layer) to create your artwork.
Steps for Sgraffito on Clay
Performing sgraffito involves several key stages, from preparing your clay to the final firing.
Prepare Your Clay
- The clay piece should typically be in a leather-hard state. This means it's firm enough to handle without deforming but still contains enough moisture to be carved smoothly without creating excessive dust or chipping. Bone dry clay can also be used, but it produces more dust and is more brittle.
Apply Underglaze or Slip
- Cover the surface of your leather-hard clay piece with one or more layers of contrasting colored underglaze or slip. Apply it evenly for consistent color.
- As demonstrated in the referenced video clip, black underglaze is a popular choice for creating bold contrast against lighter clay bodies.
Let it Dry
- Allow the applied underglaze or slip to dry until it is no longer wet and feels firm. It should be dry enough that it doesn't smear when you touch it, but ideally, the underlying clay is still in a state suitable for carving (usually leather-hard).
Plan Your Design (Optional)
- You can lightly sketch your design onto the dried underglaze surface using a pencil or a dull tool. Avoid pressing too hard, as this might start scratching the surface prematurely. Some artists prefer to carve freehand, as mentioned in the reference ("carve. Whatever i want into it.").
Carve the Design
- Using a variety of carving tools, begin to scratch or carve through the underglaze or slip layer to expose the clay underneath.
- As shown in the referenced video, a loop tool is an effective instrument for this purpose. Loop tools come in various shapes and sizes, allowing you to carve lines of different widths and depths. Other tools like sgraffito tools, needles, dental tools, or even just sharp sticks can be used depending on the desired effect.
- The depth and width of your carving will determine the final look of your design. You can create fine lines, broad areas of exposed clay, or vary the depth for textural effects.
Clean Up Dust
- As you carve, dust and dry flakes of underglaze will be created. Use a soft brush (like a fan brush) to gently brush away the dust frequently. Do not blow on the dust as it can be harmful to inhale. Collect the dust safely.
Fire and Glaze
- Once the carving is complete and the piece is bone dry, it is bisque fired.
- After the bisque firing, a clear glaze can be applied over the entire piece to seal the surface and make it food-safe (if applicable), or it can be left unglazed depending on the desired finish. The piece is then high-fired to the appropriate temperature for the clay and glaze used.
Tools for Sgraffito
A range of tools can be used for sgraffito, offering different line qualities and effects:
- Loop Tools: Excellent for removing larger areas or creating broader lines, as seen in the reference. Available in various shapes (round, square, tear-drop).
- Needle Tools: Ideal for creating fine, detailed lines and intricate patterns.
- Sgraffito Tools: Tools specifically designed with shaped tips for scratching.
- Dental Tools: Often repurposed by potters for their fine points and angled tips, great for detail work.
- Sharp Sticks or Skewers: Simple, accessible tools for basic scratching.
Tips for Successful Sgraffito
- Practice: Try the technique on test tiles before working on a final piece.
- Vary Depth: Experiment with carving shallower or deeper to see how it affects the appearance.
- Tool Angle: Holding the carving tool at different angles can produce varied line qualities.
- Contrast: Choose underglaze/slip colors that provide good contrast with your clay body for the design to stand out.
- Ventilation: Work in a well-ventilated area and clean up dust safely.
By following these steps and practicing, you can effectively use the sgraffito technique to add unique designs to your ceramic artwork.
