Sgraffito is a surface decoration technique where you apply a layer of slip or underglaze to leather-hard pottery, let it stiffen slightly, then scratch through it to reveal the clay body underneath. The contrast between the applied layer and the exposed clay creates the pattern. It’s one of the oldest decoration methods in ceramics — direct, expressive, and requires no special equipment beyond a sharp tool.
When to Apply It
Work on leather-hard clay. Apply the slip or underglaze layer when the piece is soft leather-hard — firm enough to handle but still slightly cool to the touch. Let the applied layer dry to firm leather-hard before scratching through. If you scratch too soon the slip smears; too late and it chips instead of carving cleanly.
What You Need
- Leather-hard pottery
- Colored slip or underglaze — contrasting with your clay body color
- Soft brush or sponge for applying slip
- Carving tools — loop tools, needle tools, wooden skewers, dental picks, or any pointed tool with a clean tip
Step-by-Step
1. Apply the Slip or Underglaze Layer
Brush or sponge an even coat of colored slip or underglaze over the surface. One or two coats for full, opaque coverage. The layer needs to be thick enough that scratching through it clearly reveals the clay body — thin, patchy coverage won’t give strong contrast.
- Tip: For maximum contrast, use a dark slip over light clay or a white slip over a darker stoneware. The contrast is what makes sgraffito designs readable after firing.
2. Let the Layer Stiffen
Let the applied slip or underglaze dry until it’s no longer shiny but still feels slightly cool. This usually takes 15–30 minutes depending on thickness and studio humidity. At this stage it scratches cleanly — the tool cuts through the layer without tearing or smearing.
3. Scratch Your Design
Use your carving tool to scratch through the slip layer and into (but not deep into) the clay surface. Keep strokes confident and deliberate — hesitant, scratchy marks show in the finished piece. For fine lines use a needle tool; for broader marks and textures use a loop tool or wooden skewer.
- Tip: Sketch your design lightly in pencil on paper first, then transfer the outline to the surface before carving. A pencil mark on the clay surface burns off in the kiln.
4. Remove Slip Dust
Scratching produces small flakes and dust from the slip layer. Once the piece is bone dry, use a soft brush to gently sweep away the loose material. Don’t wipe with a damp sponge while still leather-hard — it smears the scratched edges.
5. Glaze and Fire
Sgraffito can be left with a clear glaze over the whole surface, which preserves the contrast. It can also be left unglazed in the carved areas and only glazed in the slip areas — use wax resist in the scratched channels before dipping or pouring to keep them glaze-free. See: Wax Resist.
Design Approaches
Line Drawing
The most common approach — scratch botanical illustrations, geometric patterns, figures, or text into the slip layer. The line quality is similar to etching or engraving.
Reverse Sgraffito
Instead of scratching lines, scratch away the background and leave the design in the colored slip layer. The positive shapes are slip; the negative space is bare clay. More laborious but gives a very different visual effect.
Layered Colors
Apply multiple slip colors in layers, scratching through to different depths to reveal different colors. Plan the color order before starting — the bottom layer is revealed by the deepest cuts.
Related
See also: Mishima, Slip Decoration Techniques, and Wax Resist.
