Decorative Techniques

Module 4: Decorative Techniques

1. Sgraffito & Mishima with Glaze

These carving and inlay techniques add precision and contrast to glazed surfaces.

A. Sgraffito (Carving Through Glaze Layers)

• Process:

• Apply a layer of underglaze or slip to leather-hard clay.

• Let it dry slightly (not bone dry).

• Use sharp tools (needle, loop, or engraving tools) to carve designs, exposing the clay beneath.

• Apply a transparent glaze over the carved design before firing.

• Effects:

• Bold, graphic lines (e.g., geometric patterns, illustrations).

• Works best with high-contrast colors (e.g., black underglaze on white clay).

• Pro Tips:

• Keep clay at leather-hard stage for clean cuts.

• Avoid deep gouging to prevent cracking.

• Use latex resist to protect areas before carving.

B. Mishima (Inlay Techniques)

• Process:

• Carve fine lines or designs into leather-hard or bone-dry clay.

• Fill the recesses with colored slip or underglaze.

• Scrape away excess to reveal an inlaid design.

• Apply a clear glaze to enhance colors.

• Effects:

• Delicate, ceramic "tattoos" (e.g., intricate florals, calligraphy).

• Smoother than sgraffito—no raised edges.

• Pro Tips:

• Use syringes or small brushes for precise filling.

• Soften slip with a drop of vinegar to prevent shrinkage cracks.

2. Using Underglazes & Overglazes

Combining these materials expands decorative possibilities.

A. Underglazes + Transparent Glazes

• Process:

• Apply underglaze to bisque or leather-hard clay (brushed, sprayed, or stamped).

• Fire to bisque temperature (~1000°C).

• Coat with a transparent glaze (dipping or spraying).

• Final firing melts the glaze, sealing the design.

• Effects:

• Bright, painterly details (e.g., portraits, landscapes).

• Colors stay true (unlike glazes, which can shift).

• Pro Tips:

• Layer underglazes for shading (like watercolors).

• Avoid thick applications—can peel or bubble under glaze.

B. Overglaze Enamels & Lusters

• Materials:

• Enamels: Low-fire (750–850°C) colored glass powders.

• Lusters: Metallic finishes (gold, mother-of-pearl, etc.).

• Process:

• Apply to already glazed and fired pieces.

• Fire at low temperatures to melt onto the surface.

• Effects:

• Metallic accents (e.g., gilded rims, pearlized highlights).

• Jewel-like colors (enamels remain glossy and vibrant).

• Pro Tips:

• Use synthetic brushes (natural bristles burn off).

• Ventilate well—lusters contain solvents.

Workshop Activity:

1. Sgraffito Tile:

• Carve a geometric pattern through black underglaze, then coat with clear glaze.

2. Mishima Vase:

• Inlay white slip into carved vines, then glaze with celadon.

3. Overglaze Experiment:

• Paint gold luster on a fired piece, then refire.

Key Considerations:

• Test compatibility—some overglazes react with base glazes.

• Handle lusters carefully—they’re flammable before firing.